tipomac

Hello people,

I did a huge work on my 1999 Audi A8 4.2 32 valve engine code: ABZ as I have reseated all the valves, replaced 12 intake valves, cleaned all the other valves including the cylinder heads, replaced the crank case front flange, did timing belt replacement, vacuum hose replacement, breather hoses replaced …etc. I am about to finish reassembly and I have stumbled upon a bolt that I am a bit puzzled where did it come from so where should this bolt go back?

The bolt is 17mm key sized, short thread length about 15mm hex bolt. On the bolt head CLEFF 8.8 is written. Please see the attached pictures.

Would be nice if somebody could help me to figure out if I did miss something while reassembling.
Where does this bolt should go?

tipomac

Could somebody tell me what is this bolt for beside the thermostat on the A8 D2 32 valve ABZ engine?
I could not found any info about this. Not even in the Bentley repair manual.
Please see attached picture.

twentysevenlitres

Not really sure, but it looks like it could be part of the attachment for #6 in the diagram below:


Or were you asking what size it is?

tipomac

On my A8 that bolt is missing. See new picture attached.

tipomac

Thanks for this diagram but the actual bolt in question is not indicated here either.
See attached diagram where I indicate the missing bolt with a red arrow and a red dot.

twentysevenlitres

You should definately put a bolt in there as it's holding the top of that bracket marked #6 in the diagram onto the block. #6 in turn is holding two timing belt pulleys in place and looks to only have one other bolt holding it there!

I can't give you a size offhand, but it's likely to be 10mm (maybe 8mm) standard pitch.
To measure the depth (if you don't have a depth gauge), chuck a toothpick down the hole and mark where it's flush with the top.
Buy a bolt that's a few mm shorter than the hole... and a small OD washer to go with it.
Make sure the bolt is rated 8.8 or better.

(...BTW the bolt marked #8 in the diagram is listed as either an 8mm x 28mm or 8mm x 32mm (gives no explanation of the difference). So this may indicate your missing bolt is also 8mm (or it may not!).
You won't buy 28mm or 32mm over the counter, but you will get 30mm.)

tipomac

Oh, I see it now so you maybe right after all! I will definitely take some measurements to figure out what kind of bolt goes there as if it really holds that plate then it is absolutely important for sure. Tomorrow I will call a local Audi Dealer Parts department to see if they have this bolt in stock or can they order it in. They should be able to tell what exact bolt goes there to support that plate #6.

Thank you for your input on this Marty, I really appreciate it!