JFP in PA

I would also bet that the first replacement was not an OEM, but rather a cheaply made aftermarket unit. Not an uncommon problem......

The earliest cars had a slightly different oil cooler that also required an adaptor plate between the cooler and the block as well as not having the upper line........

So no bleed system in the earliest 986's -- or did they do it a different way.

Just trying to see if I need to T a line someplace to still maintain the function.

BTW, I'll need to double check tonite -- but the new coolers do not look like the will fit in the old blocks. in this case a 99 cooler (with bleed line) in a 97 block.

Mike

I'm not really sure on that one Mike; the 2.5 didn't survive in production very long, but I know they had a different cooler setup (with an adaptor plate between the cooler and the block), but cannot honestly say how it was otherwise "plumbed". I've only ever seen two of them, and that was some time ago. Perhaps if you give Jeff over at Sunset a buzz (or Jake Raby), they might have more complete info (I looked in my set of the OEM service manuals, but nothing is mentioned in the version I have).

The earliest cars had a slightly different oil cooler that also required an adaptor plate between the cooler and the block as well as not having the upper line........

Maurice-

Jeff at Sunset can set you up with everything you need (there are a fair number of bits (brackets, hoses, etc.), but they apparently have done it so often they can pull up all the part from memory). We have done several of these, all using the OEM bits for later service reasons. Only thing different is what bumper cover you chose; some just use an "S" bumper from the boneyard, others use the GT2 or 3 cover, which is a lot more stylish in my opinion, and makes it easier to clean out the side radiators as well.

Looks good; I see someone else is a "Rainforest Green" fan...................

Here's what I'm after. This is a picture of the drivers side. It's just under the cowl, and the battery cover overlaps this, and the little "T" nuts that hold the cover, lock into this and bite down, to hold it down.

It just snaps in. Passenger side is the one missing.

I think your only hope on this one is either a dealer or wrecking yard; I'm not aware of any aftermarket sources.

You will have a hard time getting any useful data while hooked to a smog machine. Here in CA they use a treadmill with a tailpipe probe and an OBD connection. They run the car at 25 mph on a treadmill. No airflow over the radiators, but the engine running at 25 mph and the vehicle at a dead standstill. Your cooling fans will be running and engine temps will be controlled by the DME fan controls, not a thermostat.

You would need to rig some sort of external cooling supplement to get coolant temperatures low enough while on the treadmill to see what effect the 160 degree thermostat has.

My only point here is everyone should understand that the 160 degree thermostat isn't going to help keeping coolant temps low once you stuck in traffic. At that point either thermostat is wide open and coolant temps are controlled by DME fan programming.

I agree with your point completely. Areas in PA that require sniffers (usually larger metro areas) are not required to use rollers, the car is warmed up (often by taking to for a short drive), then connected to the sniffer. Shops like the one we use for state emissions have a four wheel chassis dyno with an airflow fan that they use to prevent unfortunate problems that occur when the 17 year old shop low-man takes a customer's year old Ferrari out to warm it up.

What the 160 stat will do for a car stuck in traffic is to take longer for it to get hot, and then allow it to cool back to the lower base line temp when it gets moving, which is were most cars spend the majority of their time...........at least those outside of the Bay area.................

JPK,

Your methodology is quite thorough, extraordinary and has all the makings of a bid for a PhD. Add to that, all the time spent here defending it here leaves me with a more practical question; Exactly why the effort?

Regards, PK

P.S. Smog, why would someone with all the acumen of you and yours not be able to borrow some quality time on someone elses smog machine or cob together one yourselves with a dyno and some slightly obsolete (no longer certified…worthless) machine modules?

Strange as it may sound, because I am in the automotive trade, and have been during my corporate career prior to going into business for my self, I developed an inherent "need to know" concerning just about anything and everything. I read about low temp stats for the M96, and decided to test how they compare for myself. Not that I mistrust vendors as much as some posters seem to, but I do firmly believe in "trust, but verify". And I run my shop this way. So when I read about opening rates and temperature differences, I looked up how stats are tested, built a similar test stand and ran some evaluations. When customers asked me to install them in their cars, it provided an opportunity to put a data logger in their car and see how both the units worked in the real world. Now, when a customer asks, I can give him an answer that I know I can support. If you think I'm nearly anal retentive over thermostats, don't get me started on what brand and weight oils and filters we recommend for the M96; because our choice is based upon literally hundreds of UoA's over many years, and more cut up oil filters than you could imagine...................

In the age of the internet, there are lot of questionable to unsupportable product claims bantered around almost daily. I like to sleep at night and not have to worry that the shop gave someone a "bum steer"; so we do more than a little leg work on our own...................

As for "smog", we do have a non-certified "sniffer" of our own, and we do have access to a nearby state licensed "smog shop" that does the state mandated emissions for our customers. I chose not to get my shop state certified simply because of the expense and paperwork involved; we can test, we just cannot certify compliance. We also do not do A/C systems recovery and recharge for the same reasons. We can test a system to see if it is up to snuff, but discharging, Freon recovery and recharge means submitting records to the state and federal authorities for every car, regular shop inspections, etc., etc. Too much trouble, and my approach allow me more time to focus on working with customers to keep them both happy and on the road.

If the stock 185° thermostat is fully open at 200° (by your previous statement) and the fans turn go on low at 206° then both thermostats would be fully open before the fan came on. So with the exception of sudden temperature increases (not typical of stop-and-go traffic), if the fans are going on with the stock thermostat, they will also go on with the 160° thermostat.

Never said that they would not go on at the DME's preset temp, only that observations have been that it appears to take longer for the car to reach the first fan speed trip point temperature after becoming mired in traffic (which you would expect if the car was running at a lower base line temperature), that the fans do not appear to run as long a period of time before they shut off, and do not appear to run as frequently. Again, these are observations by multiple drivers, and have not been confirmed by any type of controlled experiment that I am aware of.

So why isn't anyone discussing the radiator fans involvement here? While the thermostat regulates the minimum temperature coolant parameter, the cooling fans regulate the maximum temperature parameter, which is what most people are concerned with.

The coolant temp sensor signals low speed fan operation to begin at 206 deg F. and high speed is triggerd at 216 deg F.

With inadaquate airflow over the radiators like you would experience in slow traffic or worse yet a smog test, both thermoststs will be fully open and dependant on fan airflow to control engine temperature.

Have you ever had your electric fan fail? I have. Even on a cool San Francisco winter morning, you won't last 5 to 10 minutes in traffic with a failed electric fan before your coolant temp light goes on.

However, if you were not stuck in traffic and you were moving along with sufficient airflow over the radiators, the 160 deg F thermostat would lower engine coolant temperatures below the stock thermostat. And that bothers me. I would rather see my motor have a consistent coolant temperature than one that swings from 170 to 216. Is that wide band good for the motor?

In my opinion the only way the 160 deg thermostat can be helpful is if the fan sensor temps are changed to signal operation at lower temperatures. But new sensors are just part of the solution, you also need that 3rd radiator, otherwise the fans will be on all the time leading to premature fan wear or worse, potential fan failure.

So what is really needed is a kit that includes a reduced temp thermostat, new coolant temp sensors that operate at lower coolant temperatures and a 3rd radiator to reduce the load on the cooling fans.

To my knowledge, on the M96, the fans are triggered by the DME software when the coolant reaches pre set limits; so to change the temps you would need to alter the programming. As for the fan's run time, if you read the post from Australia, the fans tend to run less frequently and for shorter periods on cars with the 160F stat. We have also noted similar observations on both two and three radiator vehicles. The addition of the third radiator on cars only equipped with two would increase both the total coolant volume and total heat exchange surface area, both of which would further reduce fan run time even further (being aware that the third unit does not have a fan of its own, so its impact would become more important when air flow over the radiators returned).

The one thing we do agree on is that we disagree.

For those who don't want to slog through the entire post, I will summarize my position:

This device is worse than stock and the vendors have concocted invalid, biased, experiments that mislead people into believing that it benefits them. It attempts to solve a non-existent problem and offers no real-life benefit other than to lighten your wallet.

The whole thing reminds me of monster cable for which nobody has claimed a longstanding independently offered $1 million reward to prove its superiority.

Caveat emptor.

If that is the case, they should also know that I am not the vendor for this product, but a satisfied customer that has personally observed its benefits, as have many of my shop's customers………………….

Oil heat Exchanger

Found one at Pelican Parts

part number:

996.107.025.57

price:

$151.75 plus shipping

I ordered the O rings as well. The next best price was $250.00 plus at Sunset, special order with a 1 week wait.

K:

How many O-rings are needed for the conversion to the "S" oil cooler? Part numbers?

Regards, Maurice.

Seven (7) total parts ordered. I'll know more after I finish the install.

996-107-025-57-M6 - Oil Heat Exchanger - $ 151.75

999-707-409-40-M17 - Rubber o-ring - .75 each - 2 needed - $1.50 total

999-707-389-40-M100 - Rubber o-ring - $1.00 each - 4 needed - $4.00 total

I hope this helps!

I've seen some part guys do this in the past, what they have given you is every possible o-ring combination available. This way, you are guaranteed to have a set that will work (the very early cars had an adaptor plate that went between the cooler and the block, necessitating additional o-rings). As the o-rings sell for a few cents each at retail, giving you all of them is cheap insurance against not having the correct set, but the cooler itself only uses four o-rings........

"data loggers, which were left in the test cars for periods ranging from five days to two weeks in order to observe how the vehicle's baseline temperatures responded in "real world" driving conditions

The issue with this test is that you are comparing the data collected with likely relevant differences (external temp, humidity, barometric pressure) in driving conditions. Additionally, it is a normal phenomenon for people with recently modded cars to drive differently to "test" out the mod and that itself skews results."

Unfortunately, you and I totally disagree on one blatantly obvious contradiction to your position: If a car consistently demonstrates a baseline operational temperature of 175-177F with one type of thermostat, and 205-210F with the other; over multiple drivers, driving conditions, weather patterns and across a protracted time frame, one of the thermostats is letting the car run at a cooler baseline temperature. Somehow, I still find that point inescapable.

"we employed a laboratory magnetic stirring hot plate and four liter glass beaker for our bench tests

Ironically, this test fails to determine the truth almost for the opposite reason the first one does: by eliminating possibly relevant variables found in real-world testing you also invalidate the test results. Such relevant variables are difficult to predict but they could possibly include non-uniformity of heating of coolant or the part itself, other external forces, vibration, turbulence in the fluid flow, etc."

You originally questioned the validity ("The rhetoric that suggests the stock thermostat doesn't actually open when it is supposed to is based on similarly uncontrolled experiments, whose results are worse than incorrect, they are misleading.") of how the opening points and full open temperatures were determined; yet when I provide you with a precisely controlled bench experiment, designed to remove any complicating outside influences, you question those results simply because they constitute the controlled environment you said was lacking. Stefan, you can't have it both way, unless of course your object is to create an endlessly circular argument that can never reach any conclusion……………. And, by-the-by, the method used exactly parallels the procedures that have been used for about 50 year to determine the opening temperatures for automotive thermostats………hardly what I would describe as "misleading".

"the manufacture was asked about this observation, they confirmed that "It is a normal observation" for the 160F stat to be observed as warming up to running temps more quickly due to increased warm water flowing sooner

I'd like to hear more about the theory of why it would warm up more quickly. Increasing the cooling capacity of the system earlier should dissipate more heat early, which should cause the temperature to rise more slowly."

You misinterpret what was described. The perception is that the cars warm up more quickly, probably due to earlier observed movement of the dash gauge and greater heater output. But this is a perception, not an experimentally confirmed fact. The dash display is well known for its lack of accuracy and linearity, so even using two cars and stopwatches to try and measure the difference in gauge movement is questionable, which is why it was described as a perception, not a fact.

Again, the thermostat does not alter the capacity of the cooling system; it alters the minimum baseline temperature at which the engine will return to under equivalent circumstances.

"none of the cars, my own included, has demonstrated any problems passing state emissions testing

State emissions tests are done at full operating temperature at which time the 160 deg thermostat performs identically to the stock thermostat. So this does not surprise me. It is during warm-up I am suggesting the emission will be higher."

I have no idea what the emissions levels are during warm up for any vehicle, but then I do not believe the testing authorities do either, or would trust such data points as particularly meaningful. From my understanding of EPA and state testing methodology, which appear to mandate emissions testing under the conditions at which vehicle will spend most of its operational life span, namely full operating temperatures, I would say that comparing "sniffer" results is both appropriate and valid.

"What this all amounts to is that it is really tricky business to design a test that gives meaningful results. Trained scientists make errors doing this all of the time. That is why we read that X causes cancer then later that X prevents cancer. While I appreciate carefully thought out experiments I just do not see the above as demonstrative of a benefit."

Stefan, why don't we just agree that we disagree on this topic? At this juncture, I do not see any form of experimental testing or empirical observations that would dissuade you from your opinion………….

I agree with the above commentary that suggests the 160 degree thermostat is ineffectual. It would be nearly impossible to perform a controlled experiment that demonstrates that it is effective as there are too many variables that cannot be controlled. I think everyone is in agreement that it won't prevent your car from overheating as the stock thermostat opens fully before that happens.

Additionally, note that the 160 degree thermostat makes the car take longer to warm up which decreases fuel economy and increases emissions.

The moral of the story is that if your car is running at normal operating temps, the stock thermostat is fully open and you're getting 100% of the benefit that at 160 degree thermostat would give with none of the ill effects.

The rhetoric that suggests the stock thermostat doesn't actually open when it is supposed to is based on similarly uncontrolled experiments, whose results are worse than incorrect, they are misleading.

Save your money on the thermostat install and instead take your lady out to a nice dinner. You'll get more mileage that way.

OK Stefan, let's go take the "rhetoric" item by item....................

"I agree with the above commentary that suggests the 160 degree thermostat is ineffectual. It would be nearly impossible to perform a controlled experiment that demonstrates that it is effective as there are too many variables that cannot be controlled. I think everyone is in agreement that it won't prevent your car from overheating as the stock thermostat opens fully before that happens."

We employed commercially available data loggers, which were left in the test cars for periods ranging from five days to two weeks in order to observe how the vehicle's baseline temperatures responded in "real world" driving conditions. And, no one ever implied that a cooler thermostat was going to prevent a vehicle from overheating; only that it would run at a cooler baseline temperature, which it does when using the 160F stat.....................

"The rhetoric that suggests the stock thermostat doesn't actually open when it is supposed to is based on similarly uncontrolled experiments, whose results are worse than incorrect, they are misleading."

Not really true. To collect information on when the stats begin to open and are fully open, we employed a laboratory magnetic stirring hot plate and four liter glass beaker for our bench tests. The hot plate has a calibrated rheostat to control the rate of heating, and an independent speed controller for the stirrer to assure constant water movement. The test thermostats (all brand new) were all suspended midway down by a wire to prevent any uneven heating effects. Each type of thermostat was tested four times, and allowed to cool to ambient temperature before subsequent tests. Each test was begun with fresh tap water that exhibited a temperature of 52-54F (measured by a digital read out thermometer with its sensor tip at the depth of the middle of the thermostat in the beaker). The stirrer was turned up to a setting of "50", and the heat was then turned on with the rheostat set to "60% power". Temperatures were observed when the thermostat first began to open, noted as a gap appearing between the center plunger section and the outer housing, and when the center plunger stopped moving and was fully open. Because of the experimental design, the rate of temperature rise allowed multiple observers to independently note the start and cessation of plunger movement, as well as the temperatures. These observations agreed within 1-2 degrees. The results are as previously summarized in early posts.......................

"Additionally, note that the 160 degree thermostat makes the car take longer to warm up which decreases fuel economy and increases emissions."

Interestingly, as far as warm up, just the opposite seems to occur. The M96 is factory equipped with some coolant by-pass flow capability, which helps provide of heater output well before the thermostat actually starts to open. Because the 160F stat starts to open, and is fully open at a low temperatures, several owners have commented that they feel the car is warming up "more quickly", most likely a perception triggered either by warmer air coming from the heater sooner, or because they see movement in the dash gauge earlier. When the manufacture was asked about this observation, they confirmed that "It is a normal observation" for the 160F stat to be observed as warming up to running temps more quickly due to increased warm water flowing sooner. Unfortunately, because the "warm up rate" perception rests with the car owner, it has not been independently or experimentally confirmed, but has been noted by multiple owners.

As for emission, as mentioned previously, I operate in a state were "sniffer" emissions testing is common. To date, none of the cars, my own included, has demonstrated any problems passing state emissions testing. While I have only seen some of the actual test values (we are not licensed to provide emissions testing), but from what I have seen, there does not appear to be any significant change in the values (HC, CO, and NO in this state) before and after moving to the cooler stat, so there does not appear to be any detrimental impact on emissions. And, again as noted previously, owners (myself included) have observed slight (2-4MPG) increases in fuel economy durng longer trips; which have not been evaluated experimentally due to significant variances in driving styles, road types, weather differences, etc., etc

Now, if you have either experimentally sound, or even significant empirical data that supports another perspective, I for one, am always open to listening and trying to learn something new...... But, in any case, have a nice Easter..................

Oil heat Exchanger

Found one at Pelican Parts

part number:

996.107.025.57

price:

$151.75 plus shipping

I ordered the O rings as well. The next best price was $250.00 plus at Sunset, special order with a 1 week wait.

K:

How many O-rings are needed for the conversion to the "S" oil cooler? Part numbers?

Regards, Maurice.

There are four orings, two each of two sizes. Parts 999-707-409-40 and 999-707-389-40 come to mind, but you better check those with a the parts department as the very early cars also used one other number.

I'd do the water pump as above. My thought is to drain and replace coolant at two year intervals when I have it on a lift to flush the brakes. Overkill? maybe, but there is a herd of folks who bought the dexcool lifetime coolant line too. In Feb 2011 when I do the brake fluid, I intend to install a 160 thermostat and replace the water pump, regaurdless of milage. If I had read about as many of them failing I would have done it last year.

When it comes to thing like the waterpump, I'd rather replace it when I want to, not when I have to.

We normally do not replace the coolant mix unless it has become contaminated or have a specific need to drain the system. As long as the mix looks good (clear with no suspended crud) and passes tests such as freeze point, pH, etc., it should be fine. Just be sure to use the OEM coolant (yes, it cost a bit more than the auto parts store stuff, but it has proven to last a long time, which the cheap stuff doesn't always do), and only mix it with distilled water (about a buck a gallon at the supermarket) and you will be fine for many years................

Can someone explain to me how, at operating temperature, a low temp thermostat is better than a regular thermostat? Once they are both open, there is no difference in coolant temperatures.

I've talked to a few race shops, and they say that if you are having coolant temp issues, installing a third radiator helps a lot more than the low temp thermostat. All the low temp thermostat does is open sooner, which therefore takes the engine longer to get to operating temperature (which is not necessarily a good thing). You might get a few more minutes of "cooler" coolant, but I doubt that affects longevity much.

There seems to be some significant misconceptions on how this works. The stat does control the minimum operation temp of the engine by controlling when full coolant flow commences (the OEM stat begins to open at 185-187F, but is not fully open until around 200F; the 160 stat begins to open at 160F and is fully open by around 170F or so), but it also controls the minimum temperature the system can return to by "throttling" the flow if the system tries to overcool (this happens most obviously in the winter, but also occurs at warmer temps as well were it controls the temperature to which the coolant will return to after becoming hotter due to being stuck in traffic, etc. ). The basic cooling system in M96 equipped cars has more heat transfer capacity (coolant to the ambient air) than the car actually needs; other wise the car would not cool back down after being stuck in traffic, or when the fans kick in. If the radiators controlled the minimum operating temperature of the system, there would simply be no need for any type of thermostatic control.

The addition of a third radiator aid in the rate at which this cooling takes place by adding more capacity, but there is already more than enough capacity built into the car without the third radiator to accomplish it, albeit over a longer period of time. In a race car, because of the uneven demands being placed upon the engine and cooling systems, cooling rates are as critical as total capacity. On street cars using the LN stat, those with two radiators took longer to cool back down than those with the third unit, but both cooled back to the same baseline temps in the mid to upper 170's, while OEM stat cars came back to a 205-210 baseline. This is the "throttling" effect of the stat……

Under EPA rules, Porsche has to build a car that will continue to pass emissions standards (those in place at the time of construction) for at least 80,000 miles. Raising the coolant temps has been a cheap band-aid in this effort since the late 1960's, and is practiced by just about all the OEM's.

I was hoping you would pipe JPF,

What's the exspensive fix? a reflash.

Interestingly, Porsche does not use 185F stats in their most performance oriented engines; the GT2 and GT3's for example use a lower temp stat to maximize engine output and longevity. Dyno tests on an M96 before and after showed that the engine picked up a small, but measurable amount of HP and torque by using the lower temp stat (actual data was published on LN Engineering's website).

This nags me, if an engine is running a 16o stat from the get go, I get can picture it. Hpwever, if a motor that has broken in at 219f for 50k ( worn to fit do a degree) is'nt dropping the temp 50 degrees all the sudden going to change all the tolerances due to a new coeifient of exspansion value. resulting in a refit of all internal components( I.E wear)?

I suppose you have had the oil anayze before and after a "stat" change on a high-ish milage motor?

Regards, PK

To respond to your first question, the expensive fix would have been to re-engineer the engine, with 'minor' upgrades such as DFI, etc. Problem is that once all the tooling and casting molds were done, no OEM is going to throw them away and start over if an easier but potentially compromising solution is available, like keeping the engine running way to hot....... Unfortunately, in the large scale production world, bean counters will always trump the engineers.

Yes, we have virgin oil analysis, UoA with the OEM stat, and UoA with the LN stat on the same brand and weight of oil and mileage used for multiple cars that began the sequence with more than 50 or 60,000 miles on them; and we have parallel data on low mileage cars as well. The oil definitely benefits from the lower coolant temps. None of the cars has demonstrated any issues (e.g.: increased oil consumption, etc.) as the result of the change. An interesting, but not fully documented change was that most owners noticed a small, but consistent improvement in gas mileage.

The factory workshop manual reccommends that the engine be warm when you change the tubes out. Either by driving it or heating it up. Does anyone know what the factory grease is? ie silicone, etc?

It appears to be silicone, but as I said, just about any lubricant will work as it is only used to help keep the o-rings in place while replacing the tubes. In a pinch, we have used use motor oil and have never had a problem.

Warming the engine helps get stuck tubes out if they are really balky.......usually, they just pop right out.

Cowl cover from a junkyard?

or

http://www.yellowdog...tails.php?id=92 ?

Mike, those are for the outer panels, not the battery cover. The quarter turn plastic ones are a dealer item.

Thank you for answers with reasoning. So the temp. gauge is kind of like the speedo, not quite right? Can you think of a quick and easy way to accurately measure my coolant temp. Regardless I don't like the idea of it running anywhere close to 210F. It just seemed like 160F was pretty low and was not sure if car would accept the change. Sounds like a good project to start on. From what I've read on these threads the only one available was the LN with housing. Is that correct?

The dash temp display is nearly a bad joke; it is both non linear and grossly inaccurate as well. Most M96's showing around 180F on the dash are actually running 205-210F.

LN has the only ones available in North America to my knowledge............

PST2 or PIWIS tester or Durametric tester will all measure all fluids accurately.

As will any OBDII scanner with PID capture capability (Actron, etc.)..............

Just got done with my spark plug change and noticed some oil in one of the spark plug tubes. From some digging around, it sounds like its either an o-ring or the tube itself so I'm planning on just replacing the whole thing. What is a good way to do this? Is it possible to just pull the tube out and just replacing an o-ring if that's all it is? I noticed on Pelican Parts they also tell you to use the Porsche grease. What do I grease and is there a similar common grease that doesn't cost $38, which is way more than the parts to fix it?

Any suggestions much appreciated. It's a 99 996 with 90,500 miles.

The grease is just to protect the o-rings while the tube is being reinstalled. In reality, just about any lubricant will work. Unless the tube is damaged, all you need is new o-rings. To pull the tubes, Porsche makes a ridiculously expensive tool, or you can use a $1 expanding one inch (2.54cm) transom plug that you can find a any boat yard............ Works like a charm.......

Under EPA rules, Porsche has to build a car that will continue to pass emissions standards (those in place at the time of construction) for at least 80,000 miles. Raising the coolant temps has been a cheap band-aid in this effort since the late 1960's, and is practiced by just about all the OEM's.

Interestingly, Porsche does not use 185F stats in their most performance oriented engines; the GT2 and GT3's for example use a lower temp stat to maximize engine output and longevity. Dyno tests on an M96 before and after showed that the engine picked up a small, but measurable amount of HP and torque by using the lower temp stat (actual data was published on LN Engineering's website).

As for emissions, were I live you can be subject to either "advanced" testing (I/M Readiness via the OBD II port), or a sniffer, depending upon the location. I have several customers running the 160F stat in M96 variants, some for a long time, and all continue to regularly pass emissions testing. The DME's in these cars are more than flexible enough to adapt to the engine running cooler.

Perhaps of more interest is that cars with the 160 stat (and have oil temp readouts) also show lower oil temperatures, often 25-30F cooler, which is a big advantage. Comparisons of UoA's on the same M96 before and after switching to the 160F stat show the oil holds up better, as you would expect from the significant drop the oil's running temps.

After monitoring several cars for a couple of years, I see no downsides to the 160F stat………..

The serp belt should have been replaced at 60k. If you are doing the thermostat, I'd replace the the waterpump, and belt if you are not positive it was done. I don't know that flushing the coolant is needed, sounds like you'll have it apart enought to just about completely drain it. You'll need two gallons of coolant and two gallons of distilled water to refill it.

Yes, I changed my serp belt myself at 62K . I might just do the waterpump and serp belt again while I'm at it.

Anybody have any thoughts on changing the waterpump with 82,000 miles as preventative maintenance?

Two thoughts: The pump isn't known to be a "survivor", and typically fails with little or no warning. Secondly, you will need to drain, refill and bleed the system a second time if the pump dies next week...........