phillipj

I just got my car serviced. I have been having starting issues when the car is warm. I replaced the battery and that took care of the problem for a month. Then the problem started happening again. I took the car to the tech to try to replicate the problem. While starting the car I got a CEL. The code was read and it was the crank positioning sensor. So I gave the go ahead to replace it and change the oil. My tech called me and said there was a problem. He sent me the picture below. Apparently those orangish bits of plastic are chain rail guides. Not good.

The car has had no issues. Runs perfect. I haven't driven it hard or tracked it since the last oil change. The car never made a strange noise or did anything out of the ordinary.

No now I ask the question. What happened? I was quoted to drop the motor and replace the guides would be in the neighborhood of $5k. That is based on that there isn't something else discovered once the engine is opened up.

Has anyone had this happen to them? Or heard of it happening?

The oil hasn't been changed in 10 months. So I have no idea when this damage occurred. As I mentioned the car runs perfect and strong.

I'm looking for advice on how to proceed.

Thank you!

Kevin

That's going to be closer to $7500 with tax and fluids. The bright side is you can replace your clutch and weld or pin all your coolant fittings (more money).. I would be curious to see if you cam sleeve are slipping.

It would really be nice to see your camshaft deviation numbers between the banks..

TTurboRoo

I am with Kevin, in fact.... I am thinking that the chain rail guide is the result of something... Not soo much the only cause! Probably moving parts that caused the guide problem to start with!

phillipj

I did not say the chain rail guide was the cause of anything. Obviously something hit it. If this happened why did I not notice it while driving? Wouldn't this have caused a loss of power or at least a noise?

Thank you Kevin for the input. I will see if I can get that data and contact you

phillipj

Can you give me an idea how and why this happened? Have you seen this before?

Kevin

This engine shares the same similar chain guides as the 964,993, and 996TT/GT3.. To get this kind of failure, one would look at the hydraulic rail tensioner. The other issue is chain failure/stretching or variocam module, exhaust cam sprocket, or intermediate shaft sprocket issues. What are your DME OverRev values? A missed shift on downshift would produce this failure. It would be very rare to have a material failure.

These type of failures suck. The good news is.. Your mechanic caught it early. I am concerned about your chains and sprockets.. I have seen chain (breaking) failures on the 996TT/GT3 engine (turns the engine into mush/junk)..

Feel free to email me.

CincyScott

This sucks. I hope you get it figured out. Keep us posted!

phillipj

Kevin I will e email you. I did not miss a shift. I haven't had my revs read since I bought the car. I will get back to you with more information.

Macster

Well, to state the obvious a chain guide composite plastic pad shed some material.

That's not enough material to be a whole pad. If the pad was entirely gone the chain would be dragging on the aluminum rail the plastic is attached to and you'd see a lot of "metal flake" (tiny alum. bits) in the oil.

With just that small amount of material I would not expect the engine to react at all. That's not likely to affect the engine much as you report the engine runs well and strong.

That there is not more debris or worse suggests very strongly to me that the pad is still substantially intact.

I can't say with any confidence though it is going to remain intact. The fact the pad shed material raises the possibility the pad has some weakness due to stress cracks, inclusions when the material was poured/cast.

Or it could be the bad spot is confined to the area that the bits came from, like a corner or leading/trailing edge of the pad and the rest of the pad is quite good and will prove to be durable.

I can't say leave it alone and drive the car. No real amount of reasonable "monitoring" of the oil filter condition is sufficient to catch a rapidly deteriorating chain guide plastic pad/rail.

But neither can I say it must be fixed.

You will have to rely upon the advise/counsel of your trusted Porsche tech for that I guess.

phillipj

Macster thank you for that. I will continue to do my research and decide what I will do. I will get some more data from the DME regarding camshaft deviation numbers on Monday as Kevin suggested. I will also read the revs to see if there is any glaring over rev that I don't recall. Thanks for your input. I appreciate it

Kevin

Macster, you forgot one detail. He is getting a DME crank position error. There is too much slack in the chain and the ECU is throwing codes.. What is worse, if the rail is delaminating plastic it is packing the oil pump screen and is scoring the vaned suction pump gear set. More important is the chance of plugging up the oil filter which will put the engine oil circuit into bypass. This will then push plastic debris into the tiny piston squirter (plug them) and plug the hydraulic intake lifters and foul the vario cam module vanes.

The best thing would be to remove the waterpump console and remove the variocam covers to inspect the 4 rails, check the condition of the timing chains and sprockets. Best is a term to hedge your bets and risk.. Best is a cautious opinion.

Ibanezgod

I feel like I need to be a mechanic to understand what is going on here... OP sorry to hear about this... scary. Would like to know the cause so I can avoid it!

Igooz

Best of luck Phillip.

Zeus993

Well blow me down. I've never heard of this issue before in a Mezger. Sorry for the OP to be going through this. Please keep us posted.

Terry Adams

Tough luck phillipj. Hope it's not major.

Our cars have similar mileage (93K for me). I just had the $8K complete water system done.

There are days I miss my air cooled 993, but I go out and do a couple boost checks and all is well again.