Engine Knocking

[Tchyk]

Worried. Over the last few weeks the engine on my 986 S, Tiptronic 37k miles, has been making a soft knocking sound that is coming from the driver side. It is very intermittent, and only after the car has warmed up. Becomes audible below 20mph and gets louder the slower you go. in park you still hear it, clearly coming from the driver side.

Although it has been quite intermittent I was lucky enough to get it to my mechanic while it was happening. His conclusion was perhaps a valve seat, or something else that would require teardown to identify. Oil filter was clean, and no other problems showing themselves at the moment.

I turn to the community, anyone have any thoughts?

Any feedback is appreciated.

[bwdz]

My first recommendation is to find a new mechanic. Anyone who just guesses valve seat and says that without doing any sort of tests should not have the word mechanic associated with them, more like a hack. There are many different tests for finding the source of a noise or a tick in the engine such as cylinder cutout tests etc... A qualified mechanic will diagnose those before blurting out some complete guess that involves an engine teardown. I can tell you how to perform these tests but since you go to a shop for your work I will be just wasting my breath as a qualified technician already knows all these.

[Gelbster]

Bank 2 is usually the first to go because it is hotter has the lest effective oil circulation.
The objective should be( in my experience) to avoid catastrophic damage. Do not run the engine other than for brief diagnostics by a competent M96 expert.
BUT FIRST !
1. Ask here for recommendations in your area to an M96 expert.A good start may be a Certified LN IMSB installer ?
2. The pan needs to come off for debris inspection (Search for exactly what to do) Filter needs to be opened up and photographed.

[Tchyk]

Thanks for the replies. Yes, you are right in assuming that your energy would be wasted, I am not a qualified technician. From my understanding the mechanic I use is quite reputable, perhaps I did not represent the shop properly, I do not want to discredit anyone. They have done good work in the past, and have very strong reviews. They are also a certified LN IMSB installer. The filter was opened and it was photographed. The car was kept and test driven to recreate the problem and they were able to do so, they mentioned bank 2 as well, but we unable to really provide anything solid without the tear down. The valve seat came up as a likely outcome as they have experienced something similar in the past. The mechanic knows full well tear down is not an option on this car, so I do not see this as an up-sell.

I do appreciate the info, if anyone else has something to add I am grateful.

[mmassey0125]

I had a similar problem with my 986S. It was the lifters. Had them replaced and the same problem occurred within a month. My mechanic tore down the engine a second time and found the same issue. Porsche covered the cost as the lifters were under warranty. Unfortunately it returned a third time. Turns out after much research and talking to porsche in Germany there is an "unofficial" explanation that some of the M96 engines had a problem with oil aeration in the area of the lifters which cause them to knock and eventually fail. They won't admit to a defect but it is known to happen with more than a handful of engines. My final solution was to sell it and by a 2006 Boxster S.

Sent from my SAMSUNG-SM-N920A using Tapatalk

[Gelbster]

The same design of lifter (made by INA ) is used in many German and even Korean cars. They all have the same interchange #. There was an upgrade but that was some years ago. The upgrade is sufficiently improved to have a new part number. I wonder if MMassey's car had the old lifters - several times over?
The old/new/Interchange lifter subject has been covered (Search).

[Tchyk]

Great feedback, thank you. After a bit more research this is sounding more like the lifters on bank 2. Any thoughts as to whether this is an engine out procedure? I'm assuming I am at some risk of damage relatively soon here, being that I've had the issue for a few weeks now.

[78F350]

Originally Posted by Gelbster

The same design of lifter (made by INA ) is used in many German and even Korean cars. They all have the same interchange #. There was an upgrade but that was some years ago. The upgrade is sufficiently improved to have a new part number. I wonder if MMassey's car had the old lifters - several times over?
The old/new/Interchange lifter subject has been covered (Search).

I remembered reading through that discussion. This one I think?
http://986forum.com/forums/performance-technical-chat/55968-hydraulic-cam-followers-2.html

[Gelbster]

Yes ,it can be done w/o removing the engine. But if you are due for a clutch/AOS/IMSB ,it is so much easier with the engine out.
You have not effectively diagnosed lifters as the cause. All of them,just on one side ,all 'went' at the same time ?
If the lifters have collapsed ,running the engine for long will damage the camshaft lobes.
There is lots in Search about diagnosing this issue.

[bwdz]

A valve seat could potentially be diagnosed with a bore scope camera. If your shop doesn't have one they can get one from Amazon for $25 or so that works with your phone. I recommend buying the $10 mirror kit that has the 30, 45 and 60 degree mirrors to look up at the valve seats, the mirrors attach to the camera so when you put it down the spark plug hole you can see up at the seats.

[Gelbster]

Originally Posted by 78F350

I remembered reading through that discussion. This one I think?
http://986forum.com/forums/performance-technical-chat/55968-hydraulic-cam-followers-2.html

Yup, That is THE thread. The 'only available in Europe for BMW' lifters are now available here. Puzzled why Pelican do not offer the generics. But Warehouse 33(Jason) and others do.
Suggest remove suspect lifter and examine before buying. There is lots in Search about post mortem of old lifters and prep of new ones. Ignore this technical tedium and much $ will be wasted.

[flaps10]

Originally Posted by Gelbster

Yes ,it can be done w/o removing the engine. But if you are due for a clutch/AOS/IMSB ,it is so much easier with the engine out.

None of those operations would be easier with the engine out with the possible exception of the AOS, but under no circumstances would I drop the engine to do an AOS.

Lifters could be done in the car but it would be tight.

[Gelbster]

I am not suggesting dropping the engine only for an AOS job !
Having recently done an engine and trans rebuild I am well aware of the issue and have posted a lot about engine +/- trans drop methods.
The point is that once there is a list of deferred maintenance/repair items, the cumulative access problems are such that dropping the engine may be a preferable option.It depends what is on your list.
Some of the seemingly simplest jobs are awful with the engine in place - for example - R&R #4 injector. or remove the airbox to fit a CAI ,paddles etc......
Belive me, I wouldn't wish an engine R&R job on anyone - without merit.

[JFP in PA]

When things get deep enough (lifters, AOS, cam paddles/timing, clutch, RMS, injectors, all in one go) dropping the engine actually saves time and reduces the chance for errors. We would not hesitate to pull one if there is a lot to be done.

[Gelbster]

But what we really need is an enthusiast video on dropping the engine+/- trans(+/- suspension??) .
So far the best by far is the JET 1 video I have linked before.
The critical equipment to make it safe & easier is the combo of a 2 post lift and a double scissor hydraulic cart. But that is a separate Thread.
http://rennlist.com/forums/boxster-and-boxster-s-986-forum/959578-drop-the-whole-thing.html
http://986forum.com/forums/general-discussions/64190-expert-engine-removal-post518965.html#post518965

[flaps10]

Yep. Next time I do it I'm going to do the whole package.

I get to practice a sub frame drop with our V10 Touareg in a few weeks.

[JFP in PA]

Originally Posted by Gelbster

But what we really need is an enthusiast video on dropping the engine+/- trans(+/- suspension??) .
So far the best by far is the JET 1 video I have linked before.
The critical equipment to make it safe & easier is the combo of a 2 post lift and a double scissor hydraulic cart. But that is a separate Thread.
Drop the whole Thing? - Rennlist Discussion Forums
http://986forum.com/forums/general-discussions/64190-expert-engine-removal-post518965.html#post518965

It can be also done using a motorcycle jack/lift with the car on jack stands.

[Gelbster]

This:
https://www.amazon.com/Double-Scissor-Hydraulic-Capacity-Height/dp/B00P5UOCZO/ref=pd_lpo_469_tr_t_3/151-0005116-8624566?_encoding=UTF8&psc=1&refRID=MAAZEHKDVEB0196S3JH3