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First - again a "Thank you" to MP for the diagram above. As you can see there are two of these L connectors (adapters). First tried new O-ring - actually made the problem worse. Which in hindsight makes sense - it further forced the crack open.
After sourcing a new L connector (with attached hose - not sold separately), I tried tackling this problem.
I was hoping to try to do this without removing the intake, which was doable, but tight. The biggest issue is the ECU electrical connector, that is right on top of this L connector.
Loosened the vacuum hoses and the rigid vacuum connector at back of intake to get some clearance. Loosened the hose from engine to the connector - while relaxing the hose clamp of course (sorry for the slight fuzziness):
Classic "oh ****" moment. The lower half of the connector was stuck in the hose!
Created a special tool for this - a dulled pick tool:
After a few nervous moments I got it out.
Removed the back connector (inside ECU tray and next to heater block):
Inserted new L connector and then tried getting the hose back on. It sucked. Clearly a time when skinny fingers 4 feet long would have been useful.... I do use fishing line on the hose clamp just in case I drop it down there.
Success!
Top off coolant (about 1 liter), test drive and no more leaks. Top off and it has held since. Nice!
Looking closely at the L connector, it was cracked at the back seam of the bleed screw neck (the original leak and problem), and the material is very weird, the plastic has clearly deteriorated. I also realized that I had gotten out the entire piece, no loose plastic pieces floating around in the cooling system. It was only two pieces originally - I broke it apart further to investigate.
Of course this raises the question - if this L connector is in this bad of a shape - what about the other? Which is impossible to get to without removing the ECU harness. The only good news here is that the one I replaced is the the supply line, the other is the return. Maybe, maybe, it will last longer due to slightly lower temperatures and less heat "shock" when high heat is called for in cold temperatures. I hope so!
Just had the same issue, so thanks so much for the post. I would smell coolant from time to time, and scoured the engine bay for signs of a leak. Finally by accident found the elbow pipe leading from the heater core with the tell tale signs of leakage. A build up of pink residue. I ordered part number 4E0819371J (67.00) and replaced. I decided to go ahead and pull the intake manifold. Replaced plugs and filters while I was at it. Gave an abundance of room to work on this, I use an Oetiker clamp on the hose in place of that difficult to use and nearly impossible to remove factory clamp. Same as you the pipe was heat soaked, and had cracked and hence the leakage. I am guessing it's only time before the more difficult one to go, the one more to the center and with less access.
Thanks gain for the post, saved me a lot of time in getting parts and getting things fixed.
Just had the same issue, so thanks so much for the post.
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Thanks gain for the post, saved me a lot of time in getting parts and getting things fixed.
Happy it was helpful - how the hxxl did we survive before Internet?
Just had the same thing happen on my 2007 S8 with 129,000 miles. Low coolant light came on last week. Filled it up today and let it run. Shut the car off and a few minutes later the fitting blew completely off and dumped coolant all over the driveway. The plastic that broke off inside the hose came mostly out, but I'm afraid there are still some small pieces in the hose.
Was relieved in a way because I didn't know where the coolant was going and was worried it might be a head gasket.
Anyway, will order parts tonight. Picking up a rental for a work trip tomorrow, guess it was as good of timing as any as it's my daily driver.
Thanks for the post as finding the part number looked difficult.
Bought the new hose, removed the plastic elbow and reinstalled using existing hose with hose clamps. Took about an hour. To replace the entire hose would definitely take at least an intake removal, maybe more.
So an S8 as well - means this is likely an age / mileage factor. We have all been around 10 years and 100k miles. it looks like.
Wonder if the 4.2s have the same issue or if the additional heat from our engines (and likely proximity to the firewall (?)) is the determining factor....
I haven't heard of one of these on a W12 so far. There was a post on a 4.2 some years ago IIRC. Seems more like a choice of materials mistake to me, plus they changed the coolant recipe about 3 times along the way with D3.
For me on W12, I had a similar experience with a one off Tee fitting way up front to which the whole coolant overflow bottle line finally connects. Just above water pump area. Plastic just crumbled apart, seemingly from the inside outward. Available only with a special order hose section from the Vaterland. I patched it for a while with some H/W store brass fitting work arounds.
05-22-2016, 02:39 PM
