Replace chain adjusters & solenoid attached to tensioner?

A local specialist recommends I have some expensive work done to change some semi-expensive engine parts based on a noise which I barely/rarely hear, and when there are no error codes. Can anyone provide any guidance/insight into whether it is safe (or safer) to wait to see if any clear symptoms emerge? Details: I believe the parts they want me to change are two of the three chain adjusters (parts 99610517958, 99610517651, and 99618055). Maybe also the solenoid attached to the tensioner (99610505158). (Plus the chain (99610517053) simply because it’s cheap to do when one is working in that area – there’s no suggestion that it is in bad shape.) The main symptom is a rough noise between 3000 and 4000 (I think closest to 4000, not sure I remember exactly). I’ve on rare occasions heard such a noise when sitting in neutral and reving the engine when cold. And possibly a milder version when driving. They say they hear it both sitting and driving. There may also be a less rough, but odd tone noticeable near & below 3000 when driving – but that may just be me looking for noises after they told me there is a problem. Another symptom which may or may not be related is the engine seeming to cut out and then abruptly kick back in on low/mid trottle while going uphill with a cold engine. This happened just once (seeming to cut out 3 times before I lifted and slowed down – by the last time, the engine speed was nearing 4000). But it’s been mentioned elsewhre in this forum that with the electronic throttle our cars have, this can result from accelerating uphill causing the right foot to lift, which causes what seems like the engine cutting out, which causes the right foot to fall towards the throttle, and the cycle continues until one either lifts completely, or floors it. Finally, on two occasions early in the summer, after parking or stalling, it’s been hard to restart the engine. Several times in a row, I’d turn the key and the engine would turn just once. Then I paused, tried again, and it started. Neither a (less experienced) Porsche guy nor a Porsche dealer heard any noise. Another (less experiened) Porsche guy said he heard something, but only, he thinks, a rattle from a catalysator that he thinks is rusty inside. Nor are there any errors which anyone’s diagnostic computer detects. And while I did hear from a (very experienced) Porsche guy that such parts needing replacing is not uncommon, he also told me there should be an error message (which not all computers will detect, apparently, but I assume that if the dealer detects no error message, there is none). This more experienced guy also told me that it’s much better to have such things replaced by someone who’s done it before. (And yes, I’d just have him look at the car if I could, but he's too far away.) So not only would I like to avoid wasting money, I’d also like to avoid messing around with an engine that seems to work pretty well. On the other hand, I’d hate to lose the engine because there’s something wrong with these bits and I do nothing about it … . Any advice on this? If there is a problem with these parts, is it dangerous to wait until it gets worse? Or can I be confident that if there are no error codes, there is nothing to worry about. Or … ? P.S. The car is an ’02 model (3.6 liter), built at the end of ’01. Thanks!

Sounds like b/s to me

You will likely get a difference of opinion. There are some who will I'm sure advise you to replace the tensioners, chain rails, chains, solenoids, and even the actuators, and who knows what else. I'm not ready to make that call. But I'm also not ready to make the call nothing needs to be done. If the solenoid or actuator are bad -- there is a pair of these per bank -- the CEL can be on and one or more error codes stored that point to the solenoid/actuator. However, there is the gotcha of the CEL can be dark yet there is still a problem. The engine can run rough, the idle can vary up and down but the CEL remains dark. If one checks pending codes there can be a pending code that points to the solenoid/actuator. (This is what happened with my Boxster when the passenger side cylinder bank solenoid/actuator went bad.) The behavior, and noise, you report can be explained by a number of other things. There is the question of the "tune" of the engine, how fresh the plugs are, the coils, the quality of the gasoline used, the type of usage, etc. The noise can be a heat shield, or a converter "brick" loose. In the case of my Boxster a loose brick upon cold start manifested a deep knock that had me contemplating engine replacement options. Once warm the car manifested a serious metallic buzz that had people at work making negative comments about the car and its noise. Fortunately a proper diagnosis confirmed the noise was not inside the engine (whew!) nor a bad heat shield (darn it) but due to a loose brick which I had addressed by replacing both exhaust manifolds. Surprisingly, while the brick was loose the converter worked pretty darn good, only very rarely triggering a CEL (P0430 -- inefficient converter) and good enough to pass smog tests. This is a crude test, but if you want you can remove the oil filter housing and dump its contents in a *clean* drain pan. If you spot a number of hard brown/nearly black plastic bits in the oil and in the folds of the filter element this can be a sign of chain guide rail deterioration. The chain guides have a composite plastic covering that the chain runs against. While this material is quite durable if a tensioner is acting up this can have the chain properly tensioned then not and this can have the chain slapping the guide rail and this can over time cause the rail covering to break up. In severe cases the material is mostly gone and the chain runs against the aluminum, but you would see enough aluminum in the oil/filter to know something was amiss. But as I said above, normally this plastic material is quite durable. When I had the solenoid/actuator in my Boxster replaced I talked to the tech about the condition of the rails that support the chain that runs between the intake and exhaust cams. He said the rails looked quite good, with no signs of serious wear. (My own experience with engines that use plastic rail covering is the plastic initially wears a bit then the wear ceases as the chain then just runs in the wear grooves it has created.) The tech believed the wear was quite acceptable and he felt there was no justification for pre-emptively replacing the solenoid/actuator on the other side nor replacing any of the other guide rails that help control the chain from the crankshaft to the IMS or from the IMS to the intake cams. Might mention this work was done with around 250K miles on the engine. But assuming the worst case, with the proper diagnostic computer the tech can check cam timing behavior to look for cam timing changes that do not occur when commanded, or the change is not the proper magnitude, or there is too much variation/variability in the timing. If work in the area of the chain guides/tensioners is necessary it is necessary to ensure the engine is in good working condition. A bad chain guide doesn't get better with time/use and will eventually lead to catastrophic failure of some kind that can ruin an otherwise perfectly good engine. The work is expensive. For my Boxster just to replace the solenoid/actuator the bill came to around $3000. (About half labor the other half parts cost. The solenoid/actuator are expensive.) Obviously doing the other side -- had the tech believed this necessary -- would have probably doubled the cost of the job and I don't want to think what it would have cost to address the other chain guides. To do these I think the engine has to come out of the car. Where does this leave you? Well, kind of right where you started. You really have to trust the tech you take the car to for something of this nature for it is kind of hard for the average owner to determine the engine needs this kind of attention on his own. As I touched upon above the work is expensive so it is I think beyond the threshold of what one would be comfortable spending on just a rather off hand diagnosis. I'm always leery of a quick/off the cuff diagnosis that has me facing spending thousands of dollars. For me I would want a CEL and error codes that indicate a problem and where the problem is, or absent a CEL pending code or codes that do essentially the same. Bits of debris, in sufficient quantity, that could only come from a failing chain guide covering would also, pardon the expression, be nice to have. Or more than one tech arriving at the same diagnosis would be another thing to have.

Thanks for so much helpful info! To be fair, the diagnosis was not entirely "off-the-cuff". They initially thought there was a problem with the cat or muffler, then concluded the adjusters needed replacing after removing some parts. But I think this only enabled them to listen more closely - I don't think they were able to see any problems. Anyway, so it seems there are a few things I can ask or have checked: (1) the oil filter test, (2) pending codes, and (3) looking for cases where the cam timing didn't do what it is supposed to do. How hard is that, by the way? Does the diagnostic software have a function that does this? Or should the Porsche dealer know how? Or ... ? Otherwise, should I be worried of side-effects of replacing these things? Any danger that someone who's not quite a water-cooled flat-6 expert might do some harm? Thanks again!

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Sounds like they are suggesting preventative maintenance suitable for a 3.4L engine but impossible for a 3.6L engine. Your shop will not be able to replace any timing chain on a 3.6L engine without completely disassembling the entire engine. If this is true I would not let them touch your car!

Also, stock 3.6L engines have variocam plus (as opposed to varicam) so they won't even have that varicam actuator 99610505158. If yours has a stock 3.6L engine, run from that shop! One way to check is look at the cam cover on the driver's side toward the front of the car. If you see the words "Variocam F1" in large fonts, that's a 3.4L. Variocam plus cam covers have the wording "Variocam Plus" in small fonts.

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Well, I feel a bit better knowing the diagnosis was after some digging. I do not like to have any engine opened up. But when it is called for I have to have complete trust in who does this. The only time I had the Boxster engine opened up was at a dealer when I had the VarioCam solenoid and actuator replaced. (Oh, I had the IMS flange/bolts replaced years ago under warranty and this was done at a Porsche dealer, too.) Replacing the chain guides/tensioners and what have you is not hard work but it requires that whoever does this knows what he is doing and does it right. There are too many places where one can pardon the expression screw up and then the cure -- replacement -- can be as bad if not worse than the problem. You have to seek out a shop that has an extremely good reputation -- and recently too -- regarding repairing the water cooled engines. I dare say even a shop that is good at air-cooled engine work is probably not the best place to take your car.

What noise are you hearing? Other symptoms? No noise is a good noise, often chain tensioners will bleed down and create this issue when they are getting tired, or fed with certain oils. If the shop isn't M96 savvy, then you certainly need to run. The wrong person holding the wrench is whats filling our schedules now. There are more problems created by typical techs than solved with these engines. This also pertains (even more so, actually) if the shop has "been doing Porsche work for 30 years".

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If this is the wrong part number, that's my fault. They told me what parts they want to replace, whare they are, etc., and for the purpose of this thread, I looked up the parts in the Porsche Katalog (the giant pdf file that has a name which I'm forgetting). I should perhaps ask them to send me the part numbers, though it seems that everyone participating in this thread understands what I mean by the chain actuators.

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Completely disassembling? I know this is a big project, and that they must remove many things, but do they really open up the engine? In fact, is it an engine-out project?

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Jake, thanks for your post. I've described the noise as best I can (not very well, since I've rarely head a noise which I think is the noise they are referring to). Perhaps I'll go start the car up later today, rev it, and see if I can duplicate (and record) this. Otherwise, if there are any other symptoms, they are the possible engine cutting out and difficulty starting mentioned above. P.S. When you say chain tensioners, do you mean the parts I've described as actuators, with the at least partly accurate parts numbers I mentioned, of which there are three and which, in the parts diagrams, look like big screws. Or do you mean the tensioner, of whcih there is one, which has a solenoid attached? Thanks again!

The tensioner is what there's 3 of that look like "big screws". You are looking at a 5 chain illustrated parts breakdown, the 3 chain (2002+) does not have these chain adjusters at all, valve timing is constantly varied by use of a vane cel adjuster on the nose of the intake camshaft. If they don't know this, you know more than they do, and you need to remove the car from there immediately.

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Yes for a 3.6L chain. It sounds to me like they have done this work on a 3.4L & don't know it is completely different for a 3.6L. This noise may be eliminated by changing your oil if it's not fresh.

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rs10, it's more than just a part number problem. Please read Jake's post #12. What Jake refers as "Chain Adjusters" is what you called the "cam actuators". This part just don't exist in the 3.6L engines. First order of business is to find out if you have a 3.4L or 3.6L then you know for sure who is confused.

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That's my guess as well.

Hmm, seems there may be a lot of confusion, entirely on my end. They did not show me the part numbers or the diagram. Rather, they drew me a simple picture and explained what the parts are. Then when discussing this with someone else, he gave me one of these part numbers. Then when I opened the "Katalog" and searched for "tensioner", I found that part number, so I assumed I was on the right page and found the other part numbers which I included in the initial post. My car's a 3.6. What I definitely remember from the guys who want to do this work is that among the things that adjust or control a chain, there is one big thing which they don't want to change, and two smaller things with the same name as each other, but different locations and prices, which they do. (They never said tensioner or adjuster, because they don't speak English.) Anyway, seems I need to get the right part numbers ... .

You can show them these pics and ask what they want to replace. post-93239-0-97733600-1397165291.jpg variocam-engine.jpg 996head.jpg variocam-plus.jpg

And hopefully the M96 expert mechanic the OP is using will be able to whip out his own diagrams/photos and draw a quick engineering sketch of the situation. Even we amateurs could do the show-and-tell and use some old parts to demonstrate. Maybe time to ask Rennlisters for a mechanic recommendation?

[Edit - the below is wrong. The right part numbers appear in post 25 below - I think.] So I finally received the part numbers from the local specialist: 996 105 179 58, and number 996 105 176 51. The parts katalog describes both as chain adjusters. Both look like big screws in the parts diagram. In both cases, the parts catalog says “see technical information group 1 NR. 10/00”

[Edit - the below is wrong. The right part numbers appear in post 25 below - I think.] ... these are in fact the first two part numbers listed in my original post. Based on my parts "katalog", this seems to fit my car (there are no years shown in the remark column). They do not want to replace the third number from my original post, which is only found on a 3.4 liter car. In the attached diagram, the parts they want to replace are numbers 24 and 34.

So having identified the parts, back to the questions: First, is it correct that these are parts for the 3.6 liter engine? How to confirm that these need to be replaced? Do all of Macster's original suggestions apply to these two parts? Any other tests? Might it make sense to wait until any further symptoms, error codes, etc. develop? Or is it the case that while this (or something like this) is reasonable preventive maintenance on a 3.4 liter car, it makes no sense on a 3.6 liter car. And fourth, is it correct that this is an engine out and open job? Something that should only be done by someone with extensive M96 experience, or, if not available, a Porsche dealer?

[Edit - this post is now irrelevant as the question I raised below is answered. Correct part numbers are in post 25 - I think.] And now I just realized that it is more complicated ... The part numbers I just listed come from the PET Katalog where I found the above picture. It is the exact same picture which the local specialist emailed me, identifying parts 24 and 34 (they did not actually send the part numbers). But in the PET Katalog, that entire picture is listed for -01 cars (with the remark "-01". For "model" M96.01/02/04. Several pages later is the three-chain diagram, for "model" M96.03 with the remark "02-". Parts numbers 24 and 34 are there too, but the part numbers are different. Yet the picture they sent me was on a printout which seems to have come from a website (partslink24.com) into which they input my VIN number, and which says 3.6 liter. Is it possible that the 5 chain diagram is correct for some 3.6 liter cars?

All 3.6 cars are 3 chain. They do NOT have the components for the 4,5 chains, hence no wear pads. If they don't know this by heart, they don't need to go there. Get your car away from there. Do it now.

Jake, thanks for the quick response! I was away from the forum looking at partslink24, where I found that even after enterring the right VIN number, it is possible to choose the wrong model year and print out exactly the page they printed out. So either they want to replace the wrong parts, or they haven't managed to communicate what they want to replace :-(((. Doesn't fill me with confidence, and getting my car out of there sounds like good advice.

However, if their mistake was merely to send the wrong part diagram, then I still have to worry that they may have identified a real problem. If they merely sent the wrong diagram, that would imply they want to replace parts 24 and 34 in the three-chain, 3.6 liter diagram. (Parts 996 105 186 00 and 996 105 188 00.) So given these part numbers, I still need to worry about most of the questions I posted in post 21 above. (In shorter form: How to confirm there is a problem, whether to wait, whether it's a mistake to do this, and whether it's an engine out/open deal?) (Some/most/all of these questions have probably already been answered, but with all the confusion about part numbers, I'm a bit lost.) Thanks!

Wanting to replace components before going invasive isn't smart anyway... If they don't know this very basic information about 3 and 5 chain engines, they lack exposure to the M96 for sure. This happens all the time... Someone called me yesterday from a shop that was trying to install a dual row IMS bearing into a single row shaft, and wondered why it wouldn't fit. Some of these people need to keep working on 40 year old Porsches, and do what they know..

Well, to be fair, I still don't really know whether they think my car has the same 5 chain system as the 3.4 liter cars. I can tell from the email chain that the service representative asked the parts guy to dig up the parts diagram which was then sent to me. So the parts guy doesn't know better, but the service rep may just have been too busy too notice (it was sent at the end of the day), and the mechanic - the guy who says he can hear that there is a problem, may know better still. So there's a very real chance that what they really want to replace are the two chain adjusters for a 3.6 with the last two part numbers I listed above. So I still need to understand how to check the diagnosis, whether such a diagnosis even makes sense on a 3.6, whether it's better to wait for an error code, etc. ...

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One thing is for sure. You know more about this, than the shop does.

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Hi there, new to this forum. I had a question regarding this topic. I have M96 (2.7 Boxster) 3-chain motor. I have recently discovered brown plastic bits in the engine oil sump pan. I wanted to ask, are the chain ramps outlined in the picture below replaceable without a complete engine rebuild. Could they also be done with the motor in the car? Currently, engine is in good health and operating smoothly, no chain rattle and deviations are all within spec. Not sure if this is cause for concern, can't find much info on the 3 chain motors with respect to chain guides. Thanks