toolo4sno

I recently replaced bad motor mounts and performed the timing belt service to my 2002 S4. After the whole job was done and engine was running, I noticed I had one 10mm bolt leftover that I cannot find a home for (DERA 8.8 marking on head). I used many different references to guide me. Aside from the Bentley manual the links are below. I am sure there were a few more guides, but those were the main ones. I removed all of the timing belt items to see if it was from there, but no luck. I haven't removed all the items for the motor mounts, but I have mentally run through it and can't visualize where it came from.

I know this is a ridiculous question, but I am hoping someone else has had a similar situation. Maybe there was a bolt that wasn't called out to remove in any of the guides, but I thought it needed to go and then didn't put it back. Grasping at straws. I am driving it, but don't dare sign up for an Open Track Day until I figure it out.

The markings on the head are the same as the 3 holding the plastic coolant tube (into thermostat) and the 3 for the TB tensioner. I thought maybe it was for that bolt holding the starter cables (?) to the motor mount bracket on the pass. side, but no luck.

I have looked: starter harness bolt, under all TB parts, holding all TB parts, upright turbo inlets.

https://www.audiworld.com/forums/sho...php?p=13646037

https://www.audiworld.com/forums/sho...php?p=14480582

https://www.audiworld.com/forums/sho....php?t=1632688

https://www.audiworld.com/forums/sho....php?t=1627759

https://www.audiworld.com/forums/sho...php?p=14491917

toolo4sno

As of right now I don't have a pic of the actual bolt, but I do have pics of two that have the same markings.

The first one is 1 of 3 holding the TB tensioner. I believe these bolts are slightly longer than the one I'm trying to find a home for, but they have the same markings.



The second one is 1 of 3 holding the coolant "tube" that comes out from the thermostat. I believe that these are the same length and type as the leftover one.


Once I get home I can get an actual photo of the bolt in question.

toolo4sno

I'm pretty sure the bolt in question is from the motor mount job or getting it open. It was the first of two main tasks and was done over the course of a few weeks. Then I did the TB and put it back together. I had difficulty with the driver's side motor mount and vaguely remember removing more than the guide(s) called for. Maybe a heat shield bolt, but I can't find it. I did passenger side first, but that seemed straight forward.


After everything was back together (first time) I originally put this bolt into the spot holding the power steering fluid cooler (bottom end driver side of lock carrier). Then I realized those bolts had black heads so I used the remaining black headed 10mm, and this one remained with no home. This bolt was placed on the work bench with other early bolts (bumper, lock carrier, maybe motor mount job) which made me think it wasn't part of the TB. I ended up tearing all of the TB stuff out to check just in case (didn't take out water pump, had all nine bolts). Still not 100% sure it's not TB related, but it wasn't obvious.

Bolt in question.

Total Length

EuroXS4

did you have the nose off the car?perhpas abumper rebar bolt?? or sway bar bolt??did you lock the crank when you did the timing belt??perhaps that bolt holds that little plastic plug into the block??then again something marked 8.8 has to be for something heavy.transmission mounts perhaps??not a camshaft gear bolt is it???only other things i can think off the the serp belt tensioner bolt for the bigger tensioner with the heavy duty spring??possibly for the y-pipe up top?

toolo4sno

The lock carrier was unhinged from drivers and opened while attached at pass. side. I have Rieger RS4 bumper, and don't have a bolt like that for it. I did lock the crank and the bolt remained with plug and is there in place currently. The bolts that hold the cam to sprocket/washer are on (16mm I think). I think the tensioner bolt you speak of is a allen head 10mm; much thicker bolt. All Y-pipe bolts are on (3 I think); never fiddled with it this job.

What sway bar bolts are you talking about? I did remove and replace 4 13mm nuts that secured the sway bar to the frame.

Does the 8.8 have meaning?

How many bolts hold the coolant tube coming out of the thermostat? I have three. They have the same markings, and are possibly same length.

shawnoc2003

Long shot, is it the bolt that holds on the aluminum tube from the y-pipe to the turbo on the passenger side? Located just below the valve cover.

toolo4sno

Nope not those. Similar bolt though. The bolt in question is an M6x20. Virtually the same bolt that holds in the crank plug. Same dims. just different markings.

shawnoc2003

Last guess------crankshaft pulley bolt????

toolo4sno

Crankshaft pulley bolt? You mean the qty8 6mm allen bolts. Not that one.

I am at a loss with this one. Aside from the 9 WP bolts and the crank shaft plug bolt I can hardly find anything that fits the M6x20 dimensions while searching in ETKA. Maybe one here and there, but I can't find the location(s) or they weren't anywhere near where I was working.

Peter Badore

8.8 is the property class or strength of the bolt. 8.8 is widely used as are 10.9 and 12.9. The higher the number is stronger the bolt. I think the 12.9 property class is about the same as an SAE grade 8 bolt.