TwoTonic

Paul and Dave-SLC,
I did catch the fuel lines "in the act" this AM. Temperatures got down close to 0 here in the mountains overnight, and that triggered the leak again. My leak did turn out to be in the high-pressure line, but not near the fuel rail. Instead, it was leaking on coupling to the hard lines near the fender--- misting out the bottom side onto that electrical bundle. A nice feature, that.
It was hard to spot, but a little blotter paper under the tubing joints showed it right away.

Anyway, the epoxy's curing overnight and I hope that gets it. I did both while I was at it. Thanks for the pointers to AudiPages ( a great resource, once again) and thanks for the feedback. A Dremel tool cutter wheel would be ideal for slicing those metal tubing ferrules, but the potential for sparks seemed a little too high.


General Grousing:
It's amazing these fuel line leaks are that common a class problem on the A8-- in a fairer world Audi would have done a recall for placing defective fuel lines to spray fuel over an electrical harness. I guess they were too busy recalling all those defective coils over on the VW side of the VAG house to bother with this one!

TT

A8CT

did they change the design? This seems to only be a pre-facelift issue but maybe it's just age.

DaveInSaltLake

The A4's, A6's, 80/90's, and 100's of the same and earlier vintage suffered from the same general problem. The only recall was for a few years of 100 or A6, IIRC.

I've had success removing the clamps with a combination of wire cutters and small needle nose pliers.

PaulW

I would of just cut the fitting off and hose clamped it. Much better repair.

<img src="http://www.audipages.com/Tech_Articles/enginemechanical/sm_DSC_5609.jpg">

I knew it!

TwoTonic

But, I have older fuel-injected cars, with more miles and 62 PSI fuel pressure on the rail, which haven't had an issue like this.

The fact that it happens only in the cold would seem to indicate that there was some sort of "tolerances over temp extremes with aging" issue that the environmental chamber testing in Ingolstadt missed. The crimp-fit system they used appears, in retrospect, like a loser. Even out of warranty, most manufacturers will go back and do a recall on a safety issue like this one.

VAG's always been a little unresponsive to this kind of class problem, unfortunately. The "bad coil" owners discovered that most recently.


Doesn't mean I dislike the car, mind you. The good far outweighs the bad. I'm just glad there's a forum like this to disseminate information about potential problems and fixes.

TwoTonic

Thanks for the pointers.

Actually, I did cut the ferrule off and 'doubled-down' on the fix, with both clamps and epoxy-based sealant. I never want to deal with this one again.

At least not until I put the twin-turbo W12 in it!

Landjet

correctly) and then since they are off the car there is no danger in using the dremel and cutting just deep enough to peel of the metal sections. Then install new hoses and regular clamps as mentioned on Audipages. Just put a rag under the fitting when removing as small amount of fuel will come out.

Landjet

Ooops, maybe I did have to use the dremel on the inner one while it was still on the car.