rbjones17

Hello all,

On the first really cold night this winter--it was about 18 degrees--I started my 1997 A8 D2 and it started and immediately stalled in the parking lot. It then cranked with a different sound as if it had no compression.

I took it to the local indie mechanic who is not experienced with Audi 4.2s. He did a leak down test on one bank of cylinders which indicated that there was no compression on any of the cylinders.

I asked him to pull the timing belt cover, and he said that the timing belt is still intact and all looks well. He could only speculate that the belt slipped a tooth on the crank, creating an out-of-time situation and no compression. He indicated that there could also be bent valves.

His recommendation along with the $400 bill was to haul it to a junk yard and get what I could out of it.

I found some used heads from a running engine.

I have two primary questions:
1) Is it possible to remove the heads without removing the engine? I am concerned that it will be impossible to get the exhaust manifolds disconnected from the exhaust pipe with the engine still in the car.
2) Is it formally possible that if rotate the crank back to TDC and put the cam locks in, that the engine might still run again and that the lack of compression could simply be due to an out-of-time situation?

The mechanic said that there was oil all over the belt, likely due to a leaking crankshaft seal and that this might have caused the slippage when trying to start the car in the cold weather.

Thanks to all in advance.

Rich in Moscow, ID.

jfrahm

It may have stripped teeth off the belt, I am surprised he did not look to see if the belt moved when the engine was cranked.

It is sort-of possible that the engine did not bend valves if it was in just the right place. I do not know what the car is worth but the shop rate for swapping on a timing belt to see if it has no bent valves is probably pretty significant. However since the bottom-end has rotated completely around it might be possible to carefully close the valves on all cylinders and do leakdowns, this would be done with the bottom end in one of the 'safe' positions, I am not sure about this engine but the Porsche 928 engine is safe at 45 degrees BTDC on the crank when the pistons are all at mid-travel. It should not matter which TDC you pick. With the crank there the cams can probably be rotated through by hand to close valves on all 8 and bent valves could be revealed.

MikkiJayne

It is definitely possible to disconnect the manifolds from the downpipes with the engine in - I've done it on mine. Its difficult, but possible. The manifolds will have to come out attached to the head though.

Extremely unlikely I'm afraid. If the timing has slipped enough such that it won't run then valve damage is inevitable in my experience. Spinning it on the starter to check compression without verifying the timing is good will pretty much seal the deal, since if it just happened to stop safe, it definitely isn't in that state any more.

Its worth trying what jfrahm suggested though to see how much damage there is (45* BTDC #5 is safe IIRC), but you really need a good look at the timing gear to see what has failed in the first instance.

If the belt is still tight I would pull the cam covers and rotate the crank slowly by hand to TDC (while making sure all 4 cams are turning!) and see if the cam locks line up. That will give you an idea of how far off it is and thus how much damage there is likely to be.

Good luck!

rbjones17

Thanks guys, I have the car on jack stands and prepped now. I am going to dig into it tomorrow. I will tell you what I find.

Rich

BrianC72gt

I've done it both ways. I removed the driver's side manifold from the head then removed the head. On the passenger's side I took them out together.

rbjones17

Well I went through the timing belt take-off procedures. The timing belt is still intact and all looked well except that there was oil all over everything; I believe I will need to replace a bunch of seals. More about that later.

So I pulled the cam cover caps off the back--this is a 32V 4.2L--and the cam lock tool on the back of the drivers side (left) cam cover snapped right into place. Getting the cam lock tool on the passenger side required me to rotate the cam sprocket at the front, clockwise an equivalent of 6 teeth.

I am unsure as to why the sprocket would have jumped 6 teeth. All of the teeth in the belt looked fine; the tensioner looked fine. I replaced both back in July and the car has run great until the one fateful night when it got into the teens and started and died.

I am now going to attempt to dive into pulling the passenger head and swapping it with another used one. Anybody have a step-by-step on how to do that?

I have found the following link which appears very helpful but it has no pictures.
Audi 32V V8 Head Job in the A8 | The Hyperlogos

I had Bentley installed on my computer but unfortunately when I upgraded to Windows 10, I can no longer get Virtual windows xp to run.

Last question: In changing out seals, I plan to change out the following previouosly posted by TerminA8r:

054 115 147 b oil pump seal for both the oil pump and crank shaft

068 103 085 e cam shaft seals

077 103 487 a
077 103 487

Cam shaft gaskets

New passenger head gasket
New passenger valve cover gasket
New half moon seals
New cam chain tensioner seals

Are there other seals that I should replace now that I have everything apart; knowing that it has 168,000 on it and likely hasn't had them changed out--the front of the engine and timing belt is covered in oil.

Thanks,

Rich

rbjones17

In changing out the oil pump seal and crankshaft seal, is the procedure simply a matter of pulling the old out with a seal puller and tapping the new ones in lie any other oil seal or is there more to it?

Thanks

Rich

the_duke

If you install the newest version of VMware you can make it work on Windows 10.

MikkiJayne

If you have 10 Pro just run it in Hyper-V

There might be a manual for it here: D2 Tech dump - A8 Parts Forum

If all else fails, post up and I'll PDF the procedure from Elsawin.

Yes on the oil seals. They're just ordinary press-in seals.

You can buy a complete head-set from Victor Reinz which is usually cheaper than buying the individual bits from Audi and just as good quality. I think for the ABZ it might come without the head gasket itself since they're handed so you could buy two sets which will get you all the top end seals, and the HG just for the side you're changing. The online catalogue is here: Catalog - VICTOR REINZ

rbjones17

Awesome thanks.

I realized that Bentley now comes online! I simply typed in my login information to their website and I can now run it from any computer.

Another question: My Bentley manual indicates to replace an oil retention valve.

Further, this oil retention valve seems to lie under the valley pan.

However neither Google nor any other half dozen Audi parts sites list a part number for a check valve for an A8D2 ABZ engine.

I was able to find the following part numbers but they don't match up with the A8D2.

Can anybody confirm if the A8D2 has the 2 "oil retention valves" and whether the following part numbers are correct for those?

Valley pan gasket: 077-103-197-D
audiusaparts.com/oe-audi/077103197d

Check valve: 079103175C
https://www.ecstuning.com/Search/079103175c/ES284337/


Thanks,

Rich