2002 3.6L lifter replacement? Difficult?

Have this 02 996 (3.6L engine), and mechanic felt certain that one of the lifters was weak. My question: How much work is it to replace the lifters? Do I have to drop the engine, or can it be done with engine in place? (I tried a search on this topic, but there are too many dead ends -- tedious.) Thanks.

what is making him think it's a lifter? I would make sure that is correct as it's very expensive to open this engine up. the noise introduced by scored cylinders is a often mistaken for bad lifters.

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My 2nd hand info is the engine can be left in the car. My first hand observation is with my 2002 Boxster which had its passenger bank VarioCam solenoid and actuator replaced which required the camshaft cover be removed along with the cams. The lifters were exposed and could have been replaced with little extra effort. My memory of this repair is getting fainter -- I have the paperwork somewhere and maybe I should search for it -- but my WAG is the labor was at least 8 hours and could have been 10 or even 12 hours. The total bill came to just over $3K and nearly half of that was parts cost. The solenoid and actuator are quite expensive items. The shop's (dealer service department) labor rate at that time was $150/hour. While I don't necessarily agree with AWDGuy's comments regarding bore scroring -- bore scoring is becoming the new buzz word whenever 996 engine problems are discussed -- one wants to be very certain the lifter or lifters need to be replaced. They can require replacement. From my recollection of reading through sections of the factory repair manual misfires can be due to the failure of one or more intake lifters and its variable lift feature. This is only present in engines that have VarioCam Plus (variable intake valve timing and variable intake valve lift). My info is the 3.6l engine introduced for the 2002 MY has VarioCam Plus. In earlier MY's the lifters can be replaced triggered by "ticking". (I came upon very low miles 2002 Carrera that required this and this was done under new car warranty but the owner refused the car because of the fact the engine needed this level of work so soon after purchase.)

I had this issue. It is important to use an "Engine Ear" skillfully to confirm the precise source of the ticking noise. As noted above ,there are many alternative and unrelated sources of the noise. There have been several updates to the lifter by INA and this has been discussed with part numbers and prices. The Interchange issue has also been discussed.Sorry I no longer have the links. The fundamental cause of 'stuck' INA lifters is perhaps a subject for a different thread but the specific mechanical cause is very simple and easy to observe. It has been discussed here before. Briefly, the tappet gets hammered and jammed hard up into the bucket. This eliminates the oil cushion normally provided by the oil-filled tappet. The excessive clearance produces noise(& camshaft wear?).The tappet has small holes/clearances so any debris or perhaps oil starvation could cause overheating & jamming ? The big question is -while you are in there do you replace all or not ? There are 24 lifters and they are expensive ! I replaced all of mine. When I say jammed ,I mean punched in so hard that extracting the tappet(out of curiosity) requires use of a a vise and a very sharp nose on a pair of Vise grips attached to a slide hammer(bodywork tool) Rislone or other snake oil will not free up tappets jammed like that.

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I don't think its a buzzword at all. It is a very real issue and in my opinion, will happen on all the engines that start to experience the oval cylinders. These bad lifter noises are often misdiagnosed. I just mentioning it as I've seen this mistake a few times now, and like you mentioned, you want to be sure. Opening that head isnt cheap. This video is actually really good to give you an idea of what scored cyl sounds like. If your mechanic is making this decision based on the noise, and hasnt physically checked the lifters yet, I'd ask him about what he thinks of the cylinders... Porsche 996/997 Engine Noise - YouTube

Very grateful for the responses. 1) No, I have no details on the lengths the mechanic went thru to diagnose the sound as a lifter. Was simply trusting his expertise -- because he found my CEL problem, which a previous $1K mechanic could not find. 2) SchnellG -- belatedly, after I had posted this, I found your post from 2014 about the lifter interchange. I'm slow: did you replace the lifters with non-Porsche alternatives? If so, how did they work out? 3) AWD-Guy -- Darn, yes, that's what it sounds like. I'll have to do some more research on this. I assume I can check with my borescope? Thanks all again.

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+996. Have him borescope from top first and if nothing is found then bottom of the cylinders before you assume it's the lifters.

AWD -I defy anyone to tell the difference between the noise of the piston slap(says Callas) in that video and a sticking lifter. It would be an interesting test for an Engine Ear. The piston slap [I]should[I] sound from the crankcase half and the lifter tick from the camshaft cover but ..... Thanks for posting that video.

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Yes, they can check with a boroscope. Mine was bad for Cyl 4 & 6. Like...really bad. The scoring happened on the thrust side of the cylinder... If it sounds like that video, I hate to tell you this....but prepare for some really bad and expensive news. here's my thread on it, it may help you. https://rennlist.com/forums/996-foru...0-project.html

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I watched hundreds of videos of different makes and so on when I thought I had scored cylinders. I was trying to find something to convince me I didn't have the issue. Unfortunately, everything I read and heard sealed the deal so much that I didnt even bother boroscoping it and tore her apart anyways. I was right. as for diagnosing it based on noise. the ones that know will be listening in certain areas of the block and for a certain rythym.

Impressive research you did. If it helps others on the bore scope - get a cheap ,color,high-res endoscope from fleabay and hook up to your laptop -works great for fitting /checking circlips when you rebuild the engine also !

I haven't heard a bad lifter in at least a decade. I've heard lots of engines that were diagnosed with a bad lifter, but that diagnosis was dead wrong. Those engines all ended up with failed pistons, leading to failed cylinders as collateral damage. These scenarios were exactly what unfolded with AWDGuy.

That's been my porsche mechanic friend experience also. said he's never done head work on the 996 but will do a few IMSB's every year and every once in a while he gets one with that infamous knock that we all know so much about.

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That's what I have (Ebay) -- works fantastic, and has far -reaching uses (5 meters, can look down drains, etc.)

In the early stages, where all you have is the "tick", the issues are seldom notable from the spark plug side of the cylinder. Why? The wear starts at BDC, so the piston skirt covers the area where the wear is most notable. Always drop the sump plate and roll the engine to TDC, and then sneak into the cylinders from below with the scope. There's today's silver bullet.

Many years ago when I was servicing rare European collectables I would use a doctors stethoscope to diagnose near exact locations of various unhappy engine noises by touching the tip of the scope to the suspect location. Worked like a charm. Used stethoscopes are cheap! Paul

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I've heard it can be done in-situ but will be very difficult in the tight space. I would imagine it's easy to damage things too. The common recommendation is usually to have the engine removed. Also you can address other PM stuff much more easily too such as AOS, timing pads, chains, etc.

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Even a new one is cheap. I think this is one of the most under deserved and under estimated tools of all time.

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Got one. I'll use it.

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Thanks. Gotta go with your experience. Is it deadly? ...or is it just bothersome and consumes oil?

" Always drop the sump plate and roll the engine to TDC, and then sneak into the cylinders from below with the scope. There's today's silver bullet . " That advice could save a confused owner thousands of $ on a futile engine 'refresh' and needless lifter replacement ! Thank you for sharing.

Stasha, is the ticking from bank 1, the same bank you found media blast material clogging the SAI ports? https://rennlist.com/forums/996-foru...ggestions.html I didn't connect the two until I re-read this thread. If blast media got sucked into the cylinder, it won't be pretty.

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Ahsai, you make Sherlock Holmes look like a chump!

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Ahsai, great thought! I think the click is on the right (opposite) side, however, I will do two things over the next few weeks: 1) Try to zero in the location with a stethoscope; 2) Drop the sump cover and go into the cylinders, from the bottom, with my borescope. Again, thanks for doing the thinking.

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Haha, maybe once I figured the connection between the blast media and his weird acting alarm. Does the bank 2 head also look very clean/blasted?

I had all the lifters replaced on bank 2 of my (previous) engine. It was a misdiagnosis for bad cats. Anyhow, it was 12 hours labor and about $1200 for the new lifters. After that I got a custom catless exhaust.

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Cats and valve lifters are very far apart so it's hard to imagine how that got misdiagnosed. Anyone with a stethoscope or even a screwdriver can tell the difference. Hope the shop reimbursed you some cost.

OP, any updates?

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Got under the car with stethoscope. One thing I did note is that it takes about a minute before the ticking sound becomes apparent. I'm thinking this might be related to oil thickness? I use 0W40 Mobil 1 Synthetic plus add in a container of ZDDP. The ticking sound is definitely on the right (passenger) side, and is heard loudest over the valve cover -- loudest at both #4 and #6. No sound heard over left bank (driver's side). Overall, the engine looks quite clean, for 175K miles. I suspect that it might have been steam cleaned just before sold (around 165K miles) -- BUT, there still is the likelihood that the right head was media blasted, suggesting media material coursing through that side too. PLAN: 1) I am waiting for 1000 more miles before I change the oil (change every 3K miles or so) -- at which time I will remove the sump plate and check in the cylinders with my borescope. 2) I will also send another oil sample to Blackstone for analysis. Because I have always worried about IMSB failure as well as other potential problems, I have gotten 2 previous oil analyses done in the past 3 years. Each time, they have come back insignificant. But now, the ticking has become louder, so I'm curious to see the results. I'm also thinking that I should run more miles before changing, in order to possibly increase the chances of detecting wear indicators. Any suggestions on any thing?

Did you also use the stethoscope on the engine block (i.e., #4 and #6 cylinders) where the heads joined the block? Jake mentioned before that bore scoring can be heard there more clearly than at the valve cover.

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I would have to say that my scope placement, except for the valve covers, was less than accurate. I did not have the car on a lift, so, with minimal ground clearance, I was placing the listening rod attached to the stethoscope against metal surface that looked like it would be in the area of the cylinders -- no eyeballs on the placement. I guess I will need to go back and confirm this more thoroughly. However, the ticking was very loud at the valve covers, passenger side. Don't know if the sound from scored cylinders would be this loud at the valve covers?

Just wanted to come back to the original question in this post, can the lifters be replaced with the engine in the car?

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They can be, BUT you will spend more time and more money doing this in the car than you will with engine removal. You will also not be able to do as thorough of a job in the car. Note: the lifters used in these engines don�t make noise when they fail. If you �hear a lifter noise� you are likely to make a huge misdiagnosis, and take a wrong turn on your way to learning a big lesson.

As far as a bad lifters, I think the intake lifters can have issues on the vario-cam plus. It isn't something that makes any lifter tick or bore scoring knock. It is something that causes misfires that can't be solved with plugs, coil swaps or replaced fuel injectors. I know people have replaced them with the engine slightly lowered, but I am not sure if that is all that easy. I believe the intake lifter can get stuck in high left mode with allows too much air or at least more air than the computer is expecting. Then misfires, then cylinder shut down. If you stop the car and restart, the cylinder is re-activated and if you are lucky, the lifter doesn't continue to get stuck in high lift. I am dealing with this right now. I had a small number of misfires every couple drives, and I have also been misfire free for 400 miles at a time. The kind of thing that puts you on the fence as far as diving in and replacing those expensive mk2 lifters.

Jake, if the COP is removed from the spark plug, will that have any acoustic difference on what is heard from a bore-score cylinder?

When my 996.2 had a sticking lifter the issue was more of a misfire and CEL vs a tapping noise. If you have a noise but no CEL I would question whether its a lifter issue

D6Lc, Sounds like I am having the same problem as you. I have an intermittent misfire in cylinder 3. I can drive several hundred miles without the misfire showing up, and even when check engine light goes on, I can't actually feel misfires. The misfires are very brief and go away on their own. If it wouldn't be for the check engine light coming on you'd never know there is anything wrong with the way the engine is running. I swapped coil and spark plug with cylinder 2, and the misfires remained on cylinder 3, so I concluded that it is not ignition related. I don't have any noise from the lifters or the engine in general. My question is how do I diagnose that it is a sticking lifter? Not sure what else can cause such an intermittent misfire.