A different V8 cooling failure.. (probably a first)

[deilenberger]

Never heard of this one before. I've had a tiny persistent leak on my S since the day I got it. Until last week it had no symptom aside from a slight coolant smell in the port (drivers side in the US) front wheel well, and a very very slow loss of coolant (I went 8,000 miles from NJ to CA up the west coast and back to NJ - and never had to top it off.) It typically took a few ounces of coolant every few months.

I had it into the dealer under CPO many times usually for other things, but asking them to check for it didn't turn up anything. At one point they thought it might be the heater hoses that come off the three aluminum pipes (I'd replaced the exploding plastic pipes proactively before failure, thinking this was a GOOD THING TO DO, and it might be those leaking - it wasn't), but that had no good effect.

Finally - just as I was leaving for a trip to the airport 60 miles away to pick up family for the holidays - I spotted a tiny puddle of coolant as I backed out the driveway. I put it up on a friend's lift and spotted some drips from the rear corner of the belly-pan (which I marked with red-marker.) This was two days before Christmas. The dealership was closed the next day, but I emailed the service manager, who called me back on Christmas eve from his home. He arranged for me to get a new Cayenne loaner to use for my airport runs, and get the car in the day after Christmas.

After lots of pressure testing and disassembly - they found a threaded plug on the back of the cooling cross-over manifold between the rear of the two cylinder heads had a drip coming off it. They ordered a new seal for it and the next day replaced it. They pressure tested it before reassembling the intake system, and found it now was sending a nice stream of coolant out instead of the weep it had before. Apparently the manifold aluminum casting had a crack in it where the plug screwed in. So - they ordered a new manifold and all the seals for the aluminum coolant pipes (since they had to be removed and replaced to install it) and all the other necessary seals - and got it back to me today (it was done last night a bit too late for me to pick it up.)

Kudos to Princeton Porsche (in NJ, USA) service department for persisting in chasing down this failure, and for accommodating me during the holiday season. It wasn't easy giving the new Cayenne back, but I told them to keep an eye out for next year for one coming in off lease for me. The new one is quite a seductive vehicle and my experience with Princeton means I have a dealership I can trust and am happy with.

Happy New Year all!

Edited December 30, 2012 by deilenberger

[txhokie4life]

Great Holiday story!

I got my new to me CTT just after Thanksgiving -- and have loved it.

Mike