JFP in PA

I am not at all surprised at your observed difference in cold start oil pressure with the OEM style filter vs. the full flow NAPA unit. That is the bypass valve in operation, allowing unfiltered oil to go around the filter media. Over the years, I have lost count of the number of OEM cartridge units we have observed with the rather flimsy bypass valve in the bottom of the housing permanently jammed open, meaning that most (if not all) of the oil is not being filtered, but generating slightly higher observed oil pressure because it is not being filtered, as there is no pressure loss across the filter media. As for the 1042 filter photo, I would have to agree with RFM, the internal metal support structure on the 1042 is substantially thicker than the outer shell housing; so if enough excessive pressure was present to deform the internals, I would expect the thinner outer housing to also be "ballooned" from it as well: I realize that does not explain how the obvious mechanical distortion occurred, but I do not believe it is from excessive oil pressure, which in any case would be limited by the relief valve on the oil pump. The NAPA 1042 is slightly more restrictive compared to the OEM style filter as the media has about a 30% finer pore diameter and is a "full flow" design (read no bypass) so that 100% of the oil is filtered 100% of the time in order to improve the effectiveness of the unit in cleaning the oil. The difference in oil pressure you observed is not unusual (85 PSIG vs. 90 with throttle application when cold), but at least in my opinion is not enough to explain the difference in the engine sounds, particularly as most engine noise complaints we see are at warm idle, when both filters are similar in oil pressure. As for you lifter observations, yes, we have seen very much the same thing, but with one additional observation: Both the VarioCam and VarioCam + system lifters are an oil passage "dead end" design (read there is no oil flow through the lifter to clean it, it enters the lifter and simply stops, leaving behind very old and dirty oil, varnish and any debris circulating within the oil system). This has always been considered a limitation of this design. It is not unusual to remove the lifters from an otherwise internally clean engine that when placed in a bath of clean thin oil and then pumped by hand immediately puke out some very black and foul smelling ugly crud. This burnt and fouled oil is the reason that these lifters develop problems, including internal wear that allows them to simply fall apart when removed, much like the burnt oil often found trapped in the IMS bearings when the rear seal is removed. Considering the dead end design, it is not at all surprising that some people have found that running thinner oil helps with the noise, but unfortunately does not offer the high temperature/ high shear protection of a higher weight oil. It also explains why some engines that are quiet at cold start, when the oil is thin, become more noisy as the oil thickens with temperature.

Obviously, Jake sees a lot more engines completely disassembled than we do, so I would be the last to refute his observations, plus there are many instances we are aware of that ultimately turned out to be confirmed cylinder issues on the M96/97 engines. He does have a valid point about cold start induced wear, particularly on engines that continue to run lower film strength 0W-40 oils as most engine wear occurs during cold start and warm up when these oils are at their weakest levels of wear protection, and the cars are often just cold started and then immediately driven without any real warm up period. If you are concerned that Jake may be correct, I would pull the plugs and bore scope the cylinders looking for signs of unusual thrust side wear patterns, which are often quite obvious even to the untrained observer.

Setting the exhaust system noise problem aside for a moment, long before I would tell a customer that he (or she) needs a very expensive cat replacement, I would have done a cat efficiency test on the side with the noise. This is a very simple and quick diagnostic that can be run with most (if not all) Porsche specific diagnostic systems that would provide a clear picture of how the unit is working. As for the welding he has observed, I would need to see the cat to be able to say if that is OEM of something done at a later time. But would also note that all of the factory cats have obvious and often crude looking welds on them from the factory: Moving back to the codes themselves, P0446 indicates a problem with the valve that is supposed to seal off the air purge line running from the EVAP canister to the intake system. These valves are known to become problematic, often because of build up in the purge lines that eventually breaks loose and jams the valve itself. While they often can be cleaned out, it is usually best to simply replace them while also blowing out the purge line itself, as they have to be removed to clean them and they are not that expensive. The P1124 and 1126 codes indicate an overly lean condition on both cylinder banks. Overly lean conditions are not a catalytic converter related fault, and as they exist on both banks, it cannot be caused by a bad cat on only one bank. They are typically the result of an air leak in the intake system, which would lead you back to the failed airline purge valve. And as I mentioned previously, many times exhaust rattling complaints on Boxster are the result of the multiple heat shields coming loose, which simply need to be reattached. While it is not my place to question the amount of the repair bill as I have no reference to the shop's hourly rate or replacement parts pricing, my larger concern would be that the correct parts were replaced and that the problems did not return, as I am having difficulty tying what the codes say to your mechanics repair track.

I have to say that I am both amazed, and somewhat concerned by several of your comments for a variety of reasons. We have many, many customers running the LN spin on set up, which I also use on my personal cars. As we always cut open every oil filter on every car we service, I have to say that we have never seen the filter element in the NAPA filters collapsed or otherwise damaged or distorted in any of the literally hundreds of oil filters we regularly see. As several of the cars we service utilize aftermarket oil pressure gauges, we have also not observed any significant differences in oil pressure when switching from one filter system to the other. And as the NAPA filter internal structure is completely supported by metal rather than the entirely treated paper construction of the OEM style filter, I would expect that the OEM filter would suffer significantly more damage if used in the same oiling system. Do you by chance save any photos of the spin on filter which failed? I am also intrigued by you oil comments for similar reasons. We have seen many customer cars with complaints of cold start noise, particularly when running the 0W-40 M1 product, that were either significantly improved or completely eliminated by moving to higher weight oils with superior film strengths compared to the M1 product. On the basis of my shop's observations over many cars, I have obviously having some difficulties understanding what you are seeing.

More to the point, it looks more like you may need to replace your mechanic,First of all, there are a lot of thing on the exhaust, like multiple heat shields that are famous for coming loose and rattling, so I would not immediately start thinking about replacing the expensive cat until appropriate diagnostics say you actually need one. As for the codes, P0446 points to a problem with the EVAP canister shut off valve on the intake purge line, which could also cause a vacuum leak. P1124 and 1126 are both O2 sensor codes that indicate that your intake system (which is attached to the EVAP purge line) has a vacuum leak because the DME cannot enrich the mixture enough to get the fuel air ratio back in spec. None of this points to bad cats, just a problem valve and possible resulting air leak, and some otherwise poorly executed diagnostics.

I'm not sure the Durametric can help you with this, it may require a PIWIS.

The VIN look up is for contributing members, perhaps now would be a good time to consider donating and becoming one?

Try rotating the engine another cycle and then check it; it should be at TDC with the pin in.

Sounds more and more like a lifter issue. Check with your local PCA chapter for a list of suggested shops in your area.

First, welcome to RennTech :welcome: While you are waiting for others to respond, let me assure you that the IMS problem is not a figment of someone's over-active imagination. There have been a substantial number of failures in the M96/97 engines, currently estimated to be somewhere around 1% of all dual row style IMS bearings (1997-2000) and upwards of 10% for all cars produced with single row bearings (2000-2005). These are Porsche's own numbers from the class action lawsuit settlement, which you can locate online if you search. The 2005-2008 cars, which use yet a third design IMS bearing also suffered failures, but the actual rate has yet not been published, but it is worth noting that Porsche eliminated the IMS shaft and bearing from all their engines with the 9A1 design engine starting in 2009.

Forgive my ignorance on this, but what "rollers" are you referring to? The other pulleys in the serpentine system.

Loose plugs can make all kinds of sounds, depending upon how loose they are. You would get anything from a tick like sound to a screeching sound. Plugs should be torqued to 30 Nm +/- 3Nm, or 22 ft. lbs. +/- 2 ft. lb.

You really have had to hear both to sense the difference, lifters make a sharper "tick" while bad cylinders tend to make a duller sound. Jake's description of where to place the stethoscope is a good one as it would localize the sound.

Porsche uses hydraulic cam followers with rather small oil passages in them that are prone to blockage and varnish like build up as they form a kind of "dead end" for the oil passages. I have not seen an additive that would help with that problem.

According to the parts system, you should have a free wheeling pulley on the alternator. That said, if the car does not have one, and you are not the original owner, it may have been changed out at some time.

If he would like to PM his VIN to me, I could tell him what is supposed to be in the car.

Porsche parts list the alternator both ways in 1999, so it did exist with the free wheeling pulley that year..

I wonder if those sensors are not applicable to my car since the values never change? The other fuel trim readings seem normal. If you take a look at post #5, I took a photo of the diagnostic screens that my reader has when it's hooked up with the engine off. It shows the above two readings for the sensors that stayed fixed as well as the other fuel trim readings that seemed to be changing appropriately with the diving conditions. Are the readings for STFTB1S2 and STFTB2S2 supposed to change? The spark plugs used on the car (according to the receipt) are: (7410) FR6LDC (I think he meant to write LDU not LDC) Those should be correct according to the manual, however I don't know the torque they used since it was a shop that did it before I owned the car. They were done 3 years and 7,000 miles ago. I thought that I read somewhere that cars with a performance tune (I have the Ultimate Motorwerks tune) eat through spark plugs much quicker and it may help to go with one step colder. Is there truth to that? Couple of thoughts: Yes, most "tuned" turbo cars benefit from running at least one step colder plugs. Secondly, have you tried measuring the same fuel trims but using a Porsche specific scan tool (Durametric, PST II, PIWIS)?

Center of photo:

That voltage should be more than enough. One item to consider is your brake light switch; there have been multiple reports of failing brake light switches causing ABS and/or PSM faults which promptly went away when the switch was replaced.

I've seen failed mounts, but I was wondering if there is an easy way to see, or test them on this actual car. I didn't look at them carefully. Maybe I can just grab the engine and shake it to see if it moves? If I am correct, they should be very easy to change on this car, right? I have a lift in my garage, so that should make it even easier. I'm not near the car now, so I can't look now. It's very possible that the mounts are bad because I always felt that the car idled a little rougher than I thought it should. I was just under the impression that it was normal because everyone says that they are a little rougher than the Boxsters and that's what I compared it to. I had a 2001 Boxster S You will need to support the engine while swapping them out, and may find that access from above may be restricted by some stuff that is removable, but they are not overly hard to change out: There are also multiple aftermarket vendors of "improved" mounts that use replacement materials like urethane to improve their strength, but also tend to impart higher vibration in the process. Because the turbo engine is a race derived unit, it shakes a bit more than the more pedestrian M96/97 street engines. If the mounts are really bad, you can usually see the engine move when someone revs it.

And these are the actual engine mounts:

Usually the rubber in the mount is either torn or has sections totally missing. This happens to be a transmission mount insert, but it will give you the basic idea:

There is no problem with the way it runs, or the sound. Everything I'm complaining about has to do with the feel. It just feels like a rough or unrefined engine for a little while after a cold start. The RPM's start that high (~1,200) but after warming a little, they settle down to 800 rpm. There are no drivability issues. All of the turbo cars have a bit of a lumpy idle when compared to the normally aspirated cars, but many times idle vagaries can be traced to failing motor mounts. If it was a failing motor mount, wouldn't it vibrate all the time? I guess it does feel the same as a bad mount, but it only does it for a short time and only on a cold start. The idle doesn't stay there. That is only when it is initially started cold. It settles in at 800 rpm, which I believe is perfectly normal. I agree, it seems to be a very difficult troubleshoot, I'm usually very good at troubleshooting, but this has me stumped! My best bet is probably to go to a mechanic that knows these cars very well so they can check it out. For all I know, it may even be a normal characteristic of these engines. Bad engine or transmission mounts usually show up only under certain circumstances, which is why they often get overlooked. When the engine is "loping" at idle, it is really trying to move around quite a bit, so a weak mount would make if feel even worse than it really is. I also would expect the car to normally run at higher RPM's than the regular idle speeds on a cold start.

All of the turbo cars have a bit of a lumpy idle when compared to the normally aspirated cars, but many times idle vagaries can be traced to failing motor mounts.