Possible Engine Failure - 2.0T CPMB

[m95roadster]

History:
Bought the car in 10/22 with 108,000 mi (now has 109600). It has an APR tune and running full e85, but I rarely get on the car. Found out afterwards that it consumes 1qt at around 750 miles. A week before the engine failure got a misfire code on #1 and #2 when over taking a car on the freeway with about 2/3 on the throttle. Cleared the codes and ran fine.

The day the problem started, I was getting a cat back exhaust installed. After it was installed I did a test drive to hear the exhaust (about 3/4 throttle, 20-50mph run). When I got to a light I noticed rattling of the muffler in the rear and some smoke from underneath me and it also sounded like there was an exhaust leak. Drove back to the muffler shop to get the exhaust readjusted. Installer said the smoke was coming from the vaseline used on the slip joint.

Started the car up and the motor had a knocking sound (similar to rod knock) so I took it into a European specialist around the corner to get it checked out. Their initial diagnosis was that the knocking was coming from under the valve cover and that a rocker more than likely moved. They wanted $1200 to remove the valve cover and confirm. I decided to tow it to my home and do it myself.

After getting the valve cover off and inspecting the cams, rockers and springs, I didn't notice anything abnormal and plugs looked ok. I decided to buy a borescope to investigate further and what I found was somewhat shocking to me. The intake valve on cylinder 3 appears to have a hole in the center of the valve. I'll post a pic of it. The left side of the pic is with the boroscope camera pointed down into the piston and the right side is the second camera pointed to the intake valve closer to cylinder 4.

What are chances the motors destroyed? HELP!!

[silver_tt]

Pic on the left is worthless, you can’t see anything. For the pic on the right it’s possible to have a burned valve but how could it have a hole in the exact center? On the other side is the stem that holds it so it would be disconnected?

[tomsgtr]

Check your piston. Look straight down and see if you see a crack.


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[m95roadster]

Pic on the left is worthless, you can’t see anything. For the pic on the right it’s possible to have a burned valve but how could it have a hole in the exact center? On the other side is the stem that holds it so it would be disconnected?

Yeah, sorry about that. The pic on the left wasn't meant to show the damage. The piston is at TDC and the camera could not focus on it properly. This boroscope took the image with the forward facing and side camera at the same time, so that is why the pic looks like that.

I'm confused about the hole in the valve as well. Usually material is gone along the perimeter of the valve.

- - - Updated - - -

Check your piston. Look straight down and see if you see a crack.


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Will do. Thanks

[Theiceman]

vales are hollow not solid, likely sodium filled ... well..... that one isn't anymore .
i would say engine is not destroyed but obviously needs work. those iron blocks are pretty robust, but head is coming off for sure

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[m95roadster]

vales are hollow not solid, likely sodium filled ... well..... that one isn't anymore .
i would say engine is not destroyed but obviously needs work. those iron blocks are pretty robust, but head is coming off for sure

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theIceman, that makes sense. Thanks for your input!

[silver_tt]

I know but something doesn't add up here. He says it's on the intake side. Aren't burned valves normally on the exhaust side and it happens around the edge of the valve, not dead center in a perfect hole, as the hot gas (too hot) passes by. It looks like something else to me, if the image of the piston was visible I would look for a witness mark. The piston doesn't have to be cracked for the valve to have made contact.

[StuckAntichris]

I know but something doesn't add up here. He says it's on the intake side. Aren't burned valves normally on the exhaust side and it happens around the edge of the valve, not dead center in a perfect hole, as the hot gas (too hot) passes by. It looks like something else to me, if the image of the piston was visible I would look for a witness mark. The piston doesn't have to be cracked for the valve to have made contact.

I agree that the burned valves are normally on the exhaust side. I believe the OP has mistaken which valve they were looking at. To me, that does look like an exhaust valve as it is flat (minus the hole) When I had my head off the intake valves were "concave" on the bottom. I think that something has failed with that valve and the head needs to be removed for a complete diagnosis. Also, that is what my piston looked like after I let a piece of valve seat get back into the cylinder. Nothing crazy but I would be inspecting that piston for cracks very carefully.

Here is a picture of my head after my valve spring broke. Notice the faces of the valves, the ones on the bottom are the exhaust.

Also a link to my repair thread for some more pictures: https://www.audizine.com/forum/showt...estroyed-Valve

Head.jpg

[m95roadster]

I agree that the burned valves are normally on the exhaust side. I believe the OP has mistaken which valve they were looking at. To me, that does look like an exhaust valve as it is flat (minus the hole) When I had my head off the intake valves were "concave" on the bottom. I think that something has failed with that valve and the head needs to be removed for a complete diagnosis. Also, that is what my piston looked like after I let a piece of valve seat get back into the cylinder. Nothing crazy but I would be inspecting that piston for cracks very carefully.

Here is a picture of my head after my valve spring broke. Notice the faces of the valves, the ones on the bottom are the exhaust.

Also a link to my repair thread for some more pictures: https://www.audizine.com/forum/showt...estroyed-Valve

Head.jpg

The side camera was definitely pointing to the intake side. I will post better pictures, but you can sort of see the concavity in the valve.

[m95roadster]

Some more pics. The picture of the valve shows the outer perimeter of the valve (lighter color). I have a video of it which shows it better, but it's too big to upload.

[StuckAntichris]

My apologies for the accusation! I think the head needs to come off to determine the cause of the failure. And to replace that valve. Keep us updated!

[m95roadster]

My apologies for the accusation! I think the head needs to come off to determine the cause of the failure. And to replace that valve. Keep us updated!

No worries, no offense taken. I agree with you on the head removal. I'm just puzzled with this valve damage (intake valve and hole in the center).

[m95roadster]

Ok, I ordered a used engine from a 2016 A5 with 56k miles. While I'm waiting for it to arrive, what parts other than the rear main seal should I replace? Thanks in advance.

FYI, the original motor had #1 rod bearing failure.

[StuckAntichris]

I hate to mention it but you should probably do the timing chains on your new engine. It has been proven that even the 2016's still get the chain stretch and I would want peace of mind. That being said, it is a lot more money on top of the engine replacement so it's up to you.

I would also look at replacing the engine mounts as well since the driver's side one is difficult to do once an engine is in the way.

Lastly, I would do a vacuum pump rebuild, RKX makes a nice kit that includes a gasket for between the block and the pump. However its not as thick as the AUDI one so I recommend getting the factory part. P/N 06H-103-121-J
https://www.rkxtech.com/products/rkx...09-a4-q5-a5-a6

Hope this helps!

[silver_tt]

does the 2016 not have the updated RMS? thought it did because a buddy has one but not 100% sure

[m95roadster]

Question: my replacement engine came out of an A5 convertible with CVT and my car has the ZF 8 speed. Will I need to swap out the flywheel on the new motor?

[StuckAntichris]

I'm not 100% sure but I would take the flex plate from your original engine and put it on your replacement engine. No need to worry about differences then. Torquing the flex plate bolts can be a bit of a pain but shouldn't be too bad. Just make sure to only spin the engine clockwise (when looking at the harmonic balancer).

[m95roadster]

I'm not 100% sure but I would take the flex plate from your original engine and put it on your replacement engine. No need to worry about differences then. Torquing the flex plate bolts can be a bit of a pain but shouldn't be too bad. Just make sure to only spin the engine clockwise (when looking at the harmonic balancer).

I appreciate all of your help.

[lhlan]

Do report back of your project's progress.

And take a picture of the valve's hole, see what's inside it!

[m95roadster]

Can the flex plate to crank bolt (8 total) and flex plate to torque converter (3 total) be reused? It is my understanding that the aluminum bell housing bolts can be used 2 times, but not sure about these.

[StuckAntichris]

Flex plate to crank cannot be reused. They get 60Nm + 90 deg when tightening. I did a criss-cross pattern. Ensure you have a good way of holding the crankshaft steady as tightening the bolts spins the engine in the wrong direction and you could mess up any timing you have done. P/N: N90665001

Flex plate to torque converter can be reused. They get 60 Nm once all of them are finger-tight. The same thing goes here. Make sure you are counter-holding the engine when you tighten these as it will spin it the wrong way. The service manual says to use the harmonic balancer holder to accomplish this

[m95roadster]

Flex plate to crank cannot be reused. They get 60Nm + 90 deg when tightening. I did a criss-cross pattern. Ensure you have a good way of holding the crankshaft steady as tightening the bolts spins the engine in the wrong direction and you could mess up any timing you have done. P/N: N90665001

Flex plate to torque converter can be reused. They get 60 Nm once all of them are finger-tight. The same thing goes here. Make sure you are counter-holding the engine when you tighten these as it will spin it the wrong way. The service manual says to use the harmonic balancer holder to accomplish this

I just got the service manual and it states to use new bolts for flex plate to crank, but no mention on flex to torque converter.

What's interesting is the part # you have shows it "fits" on some audi parts dealers, but on others it says "does not fit".

[StuckAntichris]

That part number is what I used on my 2015 Cpmb rebuild, but some others may want to chime in

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[hamfisted]

I replaced both when swapping in my 2015 engine. 8x N90665001 for flex plate & 3x N91143203 for the torque converter. I replaced all the bellhousing bolts also.

[m95roadster]

I finally removed the engine. It wasn't difficult at all, but time consuming. The hardware had no corrosion or rust anywhere and the motor mounts have very minimal wear. I guess living in Socal helps a ton. There's a rubber piece sitting below the starter mounting location that was there when the motor was pulled. It looks like some insulator/gasket for the starter. Can someone confirm this?

[SNice]

Yes! That goes with the starter. Just pulled a cpmb myself!!! Good luck!!!


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[m95roadster]

Yes! That goes with the starter. Just pulled a cpmb myself!!! Good luck!!!


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You have any tips on how to install it and keep it in place when reinstalling the engine? Thanks

[SNice]

You have any tips on how to install it and keep it in place when reinstalling the engine? Thanks

Nope - not yet. Mine is still in pieces. Almost at the point where I can start assembly. Will let you know though. Starter seems like it will be the tricky part.


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[JLAllroad]

You have any tips on how to install it and keep it in place when reinstalling the engine? Thanks

Goes between the engine bell housing and starter, lining up the starter and popping it in while doing the same thing with the motor and transmission are the fun part.

Jacking the transmission up a bit and tilting the motor back from front to rear is helpful in this ballet.


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[m95roadster]

Anyone know the torque spec for the 3 flex plate to torque convertor bolts? I could not find it in my service manual. Thanks!

[StuckAntichris]

60Nm as in my post #22 above

[m95roadster]

60Nm as in my post #22 above

I didn't even see that. Thanks man!