Engine Mounts

[NickPicks]

My 2000 A6 C5 Avant (AML engine, EAA gearbox) has just broken the other exhaust flexi pipe (the offside one was replaced last month, now the nearside one is blowing).

I asked the mechanic who changed the first one to check if the engine mounts were OK, and he said they were, and it was probably just age related wear and tear (170,000 miles, 11 years).

Now the other side has gone, I'm concerned that the engine mounts might be flexing too much and over stressing the flexis (I don't want to have to replace them again!).

Is there any method of checking the engine mounts? Is there any kind of torque reaction connection which also needs checking?

Thanks,
Nick

[JimTraining]

Hello Nick, with a bit of a risk assessment, best way is either get someone you trust to left foot brake and then engage drive (or get clutch to start to bite in a manual) and watch how much movement you get under the bonnet you can increase revs but a decent torque converter will soon beat the brakes. Can be done with a video camera (sensibly placed) and tripod if you are struggling for help. With auto boxes the ideal way would be to get the transmission in a higher gear e.g. less likely to beat the brakes or winter mode on some cars as it engages 2nd instead of 1st.

Not sure on permissible movement but less is more. My old mans volvo kept failing heater hoses and when we did a quick torque stall test the engine lifted off its mount! Careful though and keep toes, houses, pets, kids and other valuables out of the way if you do this.

Also avoid torque stalling for more than 10 seconds (at higher revs) as the cooling circuit relies on airflow over the cooler and you could quite quickly overheat the transmission. Cheers, Jim

[NickPicks]

Thanks Jim.

I've just tried that: Handbrake on hard, about 3000 rpm and try to pull away. The front of the engine seems to move up quite a bit (about 20mm from the look of it) but I've no idea how much it should move.

I've posted a video of it here http://www.youtube.com/watch?v=fxDkprMjLLU

Does anyone have any advice on whether I should replace the engine mounts?

[tinbum]

Along the same line, can you do a Vagcom scan to check their condition? I have a very intermittant Engine management light and while it was in the garage recently, they scanned and it and attributed the light to failing engine mounts. These (there are two of them i believe) are readily available and fairly simple to change. Can you tell i havent got around to it yet? Hope this adds to your post.

[JimTraining]

Nice video Nick, I would guess that that's excessive, not sure on the mount arrangement on yours, just done the same torque stall on mine, forward and reverse, and using my dipstick as a guide, rise was a max of 12mm and fall (in reverse) was less than 10mm. Not particularly scientific as its relative to revs, torque etc etc but a good indicator I suppose. The front mount on the V6 appears to connect between the front of the crankcase (offset to the o/s) and the front chassis member. If you can get in with a decent light and a camera / mirror see if the mount looks decent, cracks in the rubber / debris or stuff looking like its in the wrong place are a good guide. My dads mounts looked perfect but the bonding had failed so they simply lifted. These cup and cone mounts just end up with the cone sitting on the cup as the rubber disappears. Hopefully one of our competent colleagues can provide better info! VAG COM picking up a mount problem would be interesting, perhaps the engines reaction movement compared to output shaft movement is measured. Who knows. Cheers

[NickPicks]

Well, I bought new engine mounts, but when I looked at fitting them this morning, there's nothing wrong with the current ones - jacking up the engine, I can't feel any gaps between the cup and cone. .

I did however find that there's a front engine support / limit stop, and the rubber buffer on that has disintegrated. I've just ordered a new one from Audi, which should be turning up on Wednesday.

Does anyone have any advice on fitting this between the engine and the front member? Do I need to slide the front member out into the service position, or does the limit stop fit in with it in place?

[NickPicks]

Well, I replaced the front mount / snub mount / limit stop today.

The old one was well and truly perished and cracked. The new one is made from a soft of very stiff foam rather than solid rubber. I managed to do it without putting the front panel into the service position, although it was very tight to work in that small a space - I had to modify an 8mm allen key by cutting the short end down to about 8mm long.

I pretty much followed the method described at Audiworld forums (http://forums.audiworld.com/showthread.php?t=1710285)

The total cost was £6.85 for the bush (from Audi) and about £3 for a set of hex keys.

[JimTraining]

Thats great Nick, I wonder if any difference will be felt on shifts as per the US forum comments on Audiworld "I upgraded the snub mount because it was reported to improve shifting on the 6-speed A6s. That and it was inexpensive and (as I learned recently) easy to swap...it was worth a try!" this might explain the VAG-COM comments above perhaps.

I will put it on my to-do list. I noticed an exhaust flexi has failed so no doubt my lump is moving around too much too.

Thanks, Jim