When I pulled the codes it lit up like a Christmas tree. Misfire that and out of range this. While I was waiting for time / place to work on it I went ahead and ordered a head gasket set, dipstick tube, and a timing belt kit to get things rolling. Ah, little did know what was in store for me.

I took the front of the car off like you do with just about anything on these cars and immediately noticed that there was radiator stop leak on the front of the radiator. And on the back of the head by the transmission. Never buy radiator stop leak. That means you.

After getting the rear coolant flange off in preparation to removing the head I should have gone ahead and ordered another one right away. I thought that I could seal it up with some RTV. I was wrong. This added several days. The Audi/VW 1.8T plastic coolant flange, by the way, is just about my least favorite part of any audi where I've encountered it.

Also while removing the head on the intake manifold side I found a plastic hose going to the PCV that was torn wide open and precariously attached. I replaced that hose and attached it at the pancake valve side with a 3/4" coupler from autozone. The vacuum line from the DV (diverter valve) was not attached to anything either.

If you're having what looks like coil issues and getting this code : 17072/P0688/001672 unplug your coils and take a close look at the harnesses, under the rubber boots at the harness. If your insulation is all cracking off you're going to have to replace that whole section of harness, yay for you! Luckily 034 and Fap99 both sell pre assembled harnesses that you can splice in. You can order the individual parts from Audi if you're only doing one harness but if you're doing more than that it costs more that way than buying the pre made harnesses.

When I went to back the pins out of these harnesses they literally fell apart as so much over heated engine bay plastics are want to do. Luckily I found this out after the car had already been sitting for weeks and I'd just put the engine back together and was trying to start it.

This problem may throw this code:

17072/P0688/001672 - ECM Power Relay Load Circuit: (J271): Open Circuit

You'll want to check the resistance from the harness to the relay, there is a whole bunch of this info on the Audi forums and a diagnostic chart in the manual. Check for water in the ECU box also as that is a common problem.

Audi part numbers for rebuilding the harnesses:

• 4b0973724 harness x4
• 4b0906102 rubber grommet x4
• 000979016 0.5mm pin x2
• 000979141 1.0mm pin (or you may need two of this size instead of the .5mm, I can't remember. )
• 000979237 2.5mm pin x 6

To get the head off you have to have a special Audi head bolt tool and the bolts have to come out in a certain sequence. Here is a photo of the head off. I had two burnt/cracked valves so I'm lapping in the new ones. I also had to order a valve spring compressor. It is a universal type for overhead cams. It has a sort of bridge set up with a lever that comes down over the valve spring that fits inside the B6 head. You have to lap new valves in so that they seal right. Ideally with new valve guides and seals. I had to do this to several of the exhaust valves because they were clearly not seating to the head properly. I suspect poorly done head work after a timing belt snap. There were ham fisted mistakes all through the engine bay.

Other universal valve spring compressors wouldn't fit (advance, sears, napa, autozone, etc). You could make one out of a large c clamp and a pipe with a relief cut out of the midsection to get the valve keepers out but I figured I may be doing this again in the future..

Getting the blasted timing belt on. Be sure to mark your old belt if it didn't skip or snap. It makes this process go a heck of a lot faster. I did the water pump too as I was unsure as to the cause of the cars overheating. The water pump is much easier on the AMB than the AEB that was in my B5.

Back together after several weeks waiting on time and parts and tools, and to find out that the coil harnesses were toast.