I have been having trouble with coolant leaking lately on my 97 A6Q. I found an old post about water pumps leaking and sure enough, the impeller came loose and the shaft is leaky.

Being out of work, I undertook the project myself. When I removed the timing belt tensioner, the belt remained tight over the crank and camshafts. I carefully noted the position of the crank and camshafts.

I stretched the belt back over the camshafts as much as I could to ensure that there was no change in the number of cogs between cam gears and crankshaft on the side lacking the tensioner. As I tightened the belt, I noted slight movement on both camshafts and crankshaft, but all in the same direction, and less that one full tooth (Probably about ¼ tooth distance) on the camshaft.

I put everything back together, jumped in and crank, crank, crank... no start. Nothing, not even a cough or sputter. I didn't hear any unpleasant valve-hitting-piston sounds, but I seem to be getting nothing. Did I overlook something, or did I just misalign the camshafts after all of that? Any ideas are appreciated.

-Mark

Difficult to diagnose from here. It's too late now but you should have marked the timing belt and pulleys with white-out first. This way you would be 100% sure it was back on correctly.

If you have a VAG I would see if you can pull any codes from the car. I've never experienced this but I would guess that if the cam position sensor was reporting a mis-alignment that the ECU wouldn't fire the engine as a safety precaution.

The lack of valves hitting pistons is a good sign but I'm not sure how far off you need to be for this to happen.

Good luck.

I knew I had the timing belt on correct, and everything else was on correct. The thing I overlooked was bleeding the air out of the coolant system. After I did that it started. I can't say that was it for sure, but I think there may be some sensor that keeps things shut off if no coolant is in the system. I must have had air at that sensor if it exists, or it was just a coincidence.

I went through the firing order with a compression gauge and found piston 3 at TDC with the alignment marks lined up. is this correct?

To start I have a 1996 A6 Avant with Front wheel drive.

I would have to look at my Bentley manual again to give you all the details and that is at home (sorry). It is a pain I remember. First, make sure the coolant reservoir is filled. There is a 5?mm (I think) hex bleed valve on the coolant tube that is located on the right backside of the engine (as you are standing at the front bumper looking back). This is a tube that is running to or from the heater exchange box in the passenger compartment. This bleed valve is not very visible and is buried under a bunch of other wires/vacuum hoses etc. and is very hard to get to. Mine was stuck shut. Finally got it open though. Open the valve until coolant starts coming out and then close (I can't remember, but I may have cranked the car some or it was running while this was open to let the water pump pump the coolant through the system). I think there may have been other bleed valves that I did, but if I did they where so easy that I can't remember. Sorry for being so sketchy, but I can give you a lot more detail if you need it tonight when I get home and in front of my Bentley Manuals. Also feel free to email me directly at dennis@seaweedmonster .com or best is to call me 630-846-0164 (because I don't check email much at night). Again, let me know how it turns out. Best of luck.

To my surprise, no ECUs gave an error code. Engine still would not start.

It seems that Cyl No. 3 is at TDC, which makes me ask how that could happen without whacking a few valves in the process.

I also fail to understand how the crank could move that far. The belt was still tight around the cams and crank when the tensioner came off.

Is it risky to move the crank that far around to realign everything?