1999Porsche911

Many iof us have removed the asist spring to obtain better control of the cluch. A single pin holds it to the bracket above the pedal. Make sure you install a nail or cotter pin in the hole in the spring piston that sticks out of the housing BEFORE removing or the spring will pop out.

Just remove the fuse.

Is the noise down by your foot - or is it back by the engine?

Hi Loren,

I hear it strong below the car, almost below where I seat, that happens only when I use the clutch, like something metallic that needs grease.

The clutch system is hydraulic - so there is nothing but fluid below where you sit.

Do a search here for oiling or lubricating the clutch spring on the clutch pedal.

I tried my car doing a strong sprint from Zero, and no problem at all, it shifted to all gears up & down. Driving slow I hear a dragging noise from the clutch pedal, every time when I push it and release it, also when I arrive to my home, I ask my Son to push the clutch and only when the pedal was in, I heard a noise from the clutch in the engine compartment.

Might be the release bearing. (throwout bearing)

I have to put in 10 quarts each time. It holds 10.5 and depends on how you drain it. Angle, how long, etc.

Well, I'm a little confused here. From the first post I thought that your fans were running continuously, but the temp still stayed above 215F which is about 102C, in stop and go traffic. (It doesn't specifically say that, but that is what I thought.) In which case MR 1999s fix will not work, even he has to agree with that.

(And for the record, there is no way that turning the fans on sooner or constantly will yield a lower final coolant temperature any lower than if the fans kicked on at 215F and stayed on. Period. That is Thermo101. It WILL prevent the temperature from ever reaching 215F, or even exceeding whatever that final temperature is, but it will be the same pre or post mod. I run under the reasonable assumption that 215F max is no big deal, and there is nothing really to gain keeping the coolant constantly at 180F, at the expense of more wear & tear on the fans and the parasitic loss of the load. Using your logic, why not just hard wire the fans and keep them running all the time the engine runs?)

But when you say that the cooling system is running normal, do you mean that the fans are cycling on and off all the time in traffic? In that case, Mr 1999s fix will work exactly as he has stated, the coolant will be a more constant lower temp on average, as it will do what you stated works, move more air through the radiators. I have a 2002, and they don't seem to have the same cooling issue, as the fans infrequently turn on even in stop and go city traffic in 105F air temps. And as you stated, when the fans kick in, the temp drops very quickly, which is why I didn't suggest a higher rate fan. The ones you have work. On an aside, I had done the clutched fan delete on my BMW a few years back to "gain" a bit of HP back, as I really didn't think that the apparant small amount of air did much. I shortly re-installed it as it made a huge difference in the number of times the electric fans came on and their duration. The clutched one is much quieter and suffices for normal use. It doesn't take much air make a difference. It almost seems like the 996 with this cooling "issue" could benefit from an additional lower (quiet, less load) speed on the fans.

Hey, Perry, let me be really clear. Sorry if it seems terse, but there's a lot of broken telephone on this thread:

In high ambient temps, sitting in very slow or stationary urban traffic, the temp as displayed by the OBD can exceed 105C. This is within Porsche's parameters. But I worry about it anyway, hence the original question.

When I say the system operates as designed, I mean: The rads are clear. The coolant is less than two years old. The coolant level is correct. The coolant type is correct. The expansion tank cap is new. The fan relays turn the fans on, and switch to high speed when they are supposed to do so (102C or AC on).

This means that in the conditions described above, the fans are already on high speed at all times, but I'm still operating at 105 to 108C.

When I say that the temperature drops quickly with air flow, I mean that it does so when the car starts moving again.

Realizing that I can't manipulate too many variables in the system, I wondered whether the increased surface area and system capacity offered by the GT3 center rad made any difference at all.

That's my story. To me, the three reasonable answers would be: Yes, it will help. No, it won't make any difference. Or, stop worrying and trust Stuttgart. ;)

Thanks,

Bruce.

Well, if in fact your fans are running full speed at all times, (double check them individually) then you have a problem elsewhere. I run with AC on and fans running in 100+ stop and go traffic and coolant temperature remains below 200F, as do all the cars I know that have the fan mod. Even climbing Pike's Peak in 85f, my coolant temp never got above 205f.

You don't have to do the mod, just ground the 2 high speed relays and run that way for awhile.

U guys misread my post what I did say was with 160 thermo and housing, the baseline changes. Therefore when under highway speeds It is possible the car will run at less than 180 or somewhere cooler then when the 180 is in.! When in stop and go, the temp will go up, but when under way should cool down to a possibly less than then 215. Meaning the aggregate is less than when the 180 is in. I never said the 160 will overall keep it from going to 215 or so! My car with the 180 thermo in it with ambient temps at 50 degrees and on the hwy my car runs slightly above 180 nothing like the temps at more than 190! I agree airflow and flow determine the actuall effeciancy of the system.

No it won't. And your car will not run with a coolant temperature <180F even WITHOUT a thermostat unless you are coasting at speed downhill in cold weather.

The temperature of your coolant is determined by several factors. Volume of flow, line pressure, the speed of flow through radiators, efficiency of radiators, and volume and temperature of air flow through the radiators. There are several other factors, including the density of the fluid, etc.

Changing to a thermostat that simply opens at a lower temperature does nothing to change any of these variables.

Whether you agree with changing out the thermo as offered by L&N is not for debate here since L&N has a pretty good reputation on Porscghe rebuilds and fixes for Porsche engineering foo pahs! So based on my discussion L&N has stated there are no issues running the 160 thermo and recommendds it for hot climates and stop and go traffic. The 160 thermo just lowers the baseline of when it opens therefore giving one more time to reach the higher temps then with a 180 thermo. One has to remember Porsche has designed their engines to run in a very large variety of climates, as obvious by their recommended oil list. So to just dismiss this suggestion made by a very reputable aftermarket engineering firm is just opinion with no fact to back it up! I for one living on SE florida plan to make the thermo change. If not satsfied, just put the old one back! IIt's niot only easy to change but it will not put a huge dent in your wallet. In this case I have every bit of confidence in L&N

The 160F thermostat will not keep your engine any cooler. That has been tested many times. You can actually remove the thermostat and you will still see 215F+ in similar conditions, although running with a removed thermostat does help the engine cool down faster when airflow is applied due to do an increase in the volume and reduced pressure of coolant flow. The water pump does not have the flow it needs and airflow past the small radiators at slow speed is not sufficient.

Don't waste your time with a lower opening thermostat. You engine cannot run much lower than 190F anyway.

Increase air flow and your problem is solved.

so if i dont have a check engine light, i do have misfires? Thanks

Misfires will produce CEL.

Hi, I have a 1999 996 C4. I changed my spark plugs at 60K. I am nearing 90K now and was wondering if I need to change the spark plugs again. I know for later MY the interval was increased from 30K to 60K. Was this because newer spark plugs lasted longer?

Thanks for the help.

Oh, the car runs great and has no issues with starting.

Depends on whether you are running with copper plugs or not. However, if the car is running fine, why change? Copper will not last as long as will platinum, but both can last far longer than 30,000 miles, primarily because of unleaded fuel. Some will argue that your plugs have to be worn at 30,000 miles, and they are correct. However, so are plugs with only 1,000 miles. But both are still within operating specs and no harm will be done to your engine.

If you are a DIY kinda guy, then change them at your convenience. Otherwise, wait until they start to effect drivability. Depending on how you drive your car, even copper plugs can last 60,000+ miles.

You can pickup a loop connector at most hardware stores, cut the cable at the latch end and crimp the new connector on. Good as new.

Have you checked both radiator fans to feel if they are moving about the same amount of air? Easy to tell if you stick you hands right in front of the front tires. (Turn on the AC or you'll have to wait until summer..) Could you have a weak motor, or part of the resistor is bad on one, and that it simply is not moving enough air? The fan runs at two speeds, but is dependent onte resistor to do that. You may only have one speed.

Perhaps you have a defective T-stat that's not opening all the way? I've never understood going with lower temp t-stat, as the stock one should be full open at well below 95C. Full open is full open. AFAIK, a lower temp T-stat does not open more than the stock one. Same thing if fans are already running. Running them sooner does not keep the top temp cooler. If fans are running, then the system will reach the same equilibrium temp, regardless of when they turn on. What you may gain, is less of an excursion before they reach equalibrium. This doesn't sound like Bruces problem. I assume you've done a coolant change, and the system was properly bled. You might try Water Wetter, or as Brad inferred, a larger or additional oil cooler. though the 3rd radiator might be less expensive than the oil cooler. It's certainly cooler looking.

As I mentioned in my original post, the cooling system is entirely working as designed. I'm pretty familiar with the car by now and comfortable with this stuff. Have actually been through a fan failure, so I know how that goes. They're both clean and working fine.

I share your view on the fan mod. It might work for some, but the coolant temperature rises and falls so quickly with this car that I don't see how prophylactic cooling is going to make much difference in the traffic I drive in, other than letting the engine run cooler for a minute or two longer.

A real fix doesn't exist, frankly, IMHO. If you look at how they deal with this stuff in police cars and taxis and military vehicles, the only variables you've got are surface area, air flow and system volume: More rad, more fluid, more air. We can add only a little volume and surface area, and can only control airflow with motion. The dream solution would be a fan design that moved more air, and fan motors that can deal with the load.

Do you like make things more completcated than necessary? :o

It works for ALL. Street or track. It is not that the fans do not push enough air. It is the fact that they do not turn on soon enough to full speed.

I disagree with you. That's my right. My own experience tells me that your suggestion will not work for my needs, and your aggressiveness does nothing for your credibility.

If your water pump is working within spec and your radiators are not blocked with debris or damaged, it will work without doubt. I can't tell you how many trackers keep the fans running and maintain engine temperatures well below what you are getting.

My aggressiveness is to put an emphasis on what WILL and DOES work, contrary to what your opinion is so others know there is a real world work around to high engine temperature.

As far as your statement that the cooling system is working as designed....isn't that your problem? As designed the high speed fans do not turn on until engine temperature reaches 215F.

Have you checked both radiator fans to feel if they are moving about the same amount of air? Easy to tell if you stick you hands right in front of the front tires. (Turn on the AC or you'll have to wait until summer..) Could you have a weak motor, or part of the resistor is bad on one, and that it simply is not moving enough air? The fan runs at two speeds, but is dependent onte resistor to do that. You may only have one speed.

Perhaps you have a defective T-stat that's not opening all the way? I've never understood going with lower temp t-stat, as the stock one should be full open at well below 95C. Full open is full open. AFAIK, a lower temp T-stat does not open more than the stock one. Same thing if fans are already running. Running them sooner does not keep the top temp cooler. If fans are running, then the system will reach the same equilibrium temp, regardless of when they turn on. What you may gain, is less of an excursion before they reach equalibrium. This doesn't sound like Bruces problem. I assume you've done a coolant change, and the system was properly bled. You might try Water Wetter, or as Brad inferred, a larger or additional oil cooler. though the 3rd radiator might be less expensive than the oil cooler. It's certainly cooler looking.

As I mentioned in my original post, the cooling system is entirely working as designed. I'm pretty familiar with the car by now and comfortable with this stuff. Have actually been through a fan failure, so I know how that goes. They're both clean and working fine.

I share your view on the fan mod. It might work for some, but the coolant temperature rises and falls so quickly with this car that I don't see how prophylactic cooling is going to make much difference in the traffic I drive in, other than letting the engine run cooler for a minute or two longer.

A real fix doesn't exist, frankly, IMHO. If you look at how they deal with this stuff in police cars and taxis and military vehicles, the only variables you've got are surface area, air flow and system volume: More rad, more fluid, more air. We can add only a little volume and surface area, and can only control airflow with motion. The dream solution would be a fan design that moved more air, and fan motors that can deal with the load.

Do you like making things more completcated than necessary? :o

It works for ALL. Street or track. It is not that the fans do not push enough air. It is the fact that they do not turn on soon enough to full speed.

Have you checked both radiator fans to feel if they are moving about the same amount of air? Easy to tell if you stick you hands right in front of the front tires. (Turn on the AC or you'll have to wait until summer..) Could you have a weak motor, or part of the resistor is bad on one, and that it simply is not moving enough air? The fan runs at two speeds, but is dependent onte resistor to do that. You may only have one speed.

Perhaps you have a defective T-stat that's not opening all the way? I've never understood going with lower temp t-stat, as the stock one should be full open at well below 95C. Full open is full open. AFAIK, a lower temp T-stat does not open more than the stock one. Same thing if fans are already running. Running them sooner does not keep the top temp cooler. If fans are running, then the system will reach the same equilibrium temp, regardless of when they turn on. What you may gain, is less of an excursion before they reach equalibrium. This doesn't sound like Bruces problem. I assume you've done a coolant change, and the system was properly bled. You might try Water Wetter, or as Brad inferred, a larger or additional oil cooler. though the 3rd radiator might be less expensive than the oil cooler. It's certainly cooler looking.

Running the fans on high, sooner, does in fact keep the engine cooler in all conditions. Themostat is not the problem, airflow is. You can remove the thermostat and you'll have the same problem.

You know, I know it's a popular mod and a lot of folks have had overheating issues (maybe '00 specific), specially on the track, but I've NEVER had overheating issues, let alone high temps in my car with the standard 2 radiators, even on the track during the middle of the summer at places like Buttonwillow and Thunderhill, which get 100 degree temps in the summer ambient.

I will say though, every time I wash the car, I spray high pressure water at the radiators to keep them clean.

Oh, and it's a C4s.

I agree that the cooling system works brilliantly when there is airflow through the rads, as would be the case on a track. The problem is sitting in traffic. Indeed, it might only be a problem in my head; the car is working as designed. I just don't think the car was designed with the stresses of urban commuting strictly in mind.

Regarding the model year, I think that I've read that the early 996s had only one temperature sensor, located at the engine. The later ones had a second sensor at the rads, and the OBD read out the average of the two readings, thus making the later cars appear to run cooler than the earlier ones did. C

The target coolant temperature is 90C - 95C. You cannot run at that low of a temperature if moving in slow traffic without getting more air past the radiators.

I'm sure you're right. The only really correct, effective fix would be fans that moved more air.

The method for correcting your problem is to have the existing fans come on sooner in the temperature range. This will provide you a consistantly cooler engine in all conditions. There are many ways to acheive this, including my fan mod as is outlined on this site, changing the inline sensor for the fans, intercepting signal to DME, etc.

You know, I know it's a popular mod and a lot of folks have had overheating issues (maybe '00 specific), specially on the track, but I've NEVER had overheating issues, let alone high temps in my car with the standard 2 radiators, even on the track during the middle of the summer at places like Buttonwillow and Thunderhill, which get 100 degree temps in the summer ambient.

I will say though, every time I wash the car, I spray high pressure water at the radiators to keep them clean.

Oh, and it's a C4s.

I agree that the cooling system works brilliantly when there is airflow through the rads, as would be the case on a track. The problem is sitting in traffic. Indeed, it might only be a problem in my head; the car is working as designed. I just don't think the car was designed with the stresses of urban commuting strictly in mind.

Regarding the model year, I think that I've read that the early 996s had only one temperature sensor, located at the engine. The later ones had a second sensor at the rads, and the OBD read out the average of the two readings, thus making the later cars appear to run cooler than the earlier ones did. C

The target coolant temperature is 90C - 95C. You cannot run at that low of a temperature if moving in slow traffic without getting more air past the radiators.

Or you can keep your coolant temperature below 200F at all times by doing my simple fan mod. Cost is virtually nothing.

normal.. you are now hearing the tranny. No dual mass to dampen the noise :)

B

It is a normal noise of the LWFW. The LWFW often changes the harmonic balance of the crank and produces the noise due to vibration of the shaft. Technically, this is not good for the crank bearings and the choice you have to make is whether the added performance you get from the LWFW is worth the risk of possible bearing damage.

New to me 99 C2 coupe. One night last week my battery mysteriously drained overnight. It has only happened once in the 3 weeks I have owned it.

I read as much as I could find on this subject in previous posts and am now going to track it down (trunk light, "in series" ammeter test etc.), but I have a question before I go through it.

I read that: 1)If you leave the key in the ignition, even if it is off, it can kill the battery and 2) If you leave a manual trans car in gear, it can kill the battery.

I know I left the key (off) in the ignition once and left it in gear once overnight. I can't remember if those times correlated with the battery drain, but what I'd like to know is can either one of these things really kill the battery overnight? I read both these things in previous posts, but I'd like conformation if anyone here knows the facts.

Thanks,

Doug

Leaving the key in the ignition WILL slowly drain the battery. Leaving your transmission in gear, which is what you should be doing, has NO EFFECT on the battery.

Where exactly does the resistor go? Anyone have a write up on this?

Cut the MAF cable white wire (pin #5) and splice back together with the resister inline.

First check the fuel pump fuse.

ok this is definatly only happening after like a start to move out of garage then stop outside pop indoors lock door come out try to start it dont kick in straight away.... after any normal 5 min journey starts fine everytime its just stop and start it wont fire up for 10-20 secs of turning over then splutters to life ?

Very common with fuel injected engines. Short operation < 1 minute or so, can cause the engine to become rich making it difficult to start shortly thereafter.

Have you tried vinegar?

Any increase in performance you feel is only due to having new, properly functioning plugs and not because they are better plugs. A spark is a spark. The compressed mixture in the cylinders will ignite no better with a hotter spark than with the minimum required spark. For a high compression performance engine, the best plug is a copper core plug and, ironically, these are the least expensive plugs.

What was the CEL code?