Got done shopping, and drove about 600 feet when I noticed vapor coming out from the hood of my '12 S. Pulled over immediately into an open stall as the low coolant alert displayed. Found 500 feet of large coolant trailing from where we stopped, but the parking stall we started from didn't have a drop a drop on it.

Under the hood, coolant was on the front and on the top of the engine/ compartment. Could this be from a thermostat, thermostat housing, or water pump? The sudden massive leak indicates a large failure somewhere.

I'm so glad it happened in a parking lot rather than rush hour traffic. I dont think engine damage from overheating is likely.

I would love to get some insights from you!

 

Front of the engine - sounds most likely the water pump.. or one of the myriad of hoses and plastic connections..

Let us know what's found.

 

Thanks for the reply. Soonest any of the local shops can get to it is next week. I'm tempted to start doing an analysis myself with a coolant pressure test. If it ends up being something simple (Ha!) like a Thermostat housing, maybe I can get one ordered and installed by Thursday....

 

I looked at the service manual on the thermostat housing. Simple is not a word I'd associate with replacing it.

 

"Simple is not the word..." Yes, I believe that!

Just borrowed a coolant pressure test kit, and started putting water in the reservoir tank. It started dripping out the bottom of the car before the first gallon was completely poured in. Can't see the leak yet. Time to start removing the under tray and HOPE for a simple fix...

 

Water is leaking out from the engine/Xmsn area. Which rules out any easy fixes....as far as I know. Looks like I'm booking up time with the dealer.

Any guesses on a no-pressure leak exiting that area? Water pump?

 

No guesses. There are MANY hoses/fittings all around the engine - and any one of them could be the cause. There were some issues with a fitting on the cross-bridge behind the two cylinder heads having the fitting work loose. Not "common" but not unknown. When it comes out it leaves a hole about 5/8" in diameter. Official fix is a new bridge (which CAN be installed without engine removal - not easily - but it can..) unofficial fix would be to clean and dry the area well, then JB Weld the sucker back in place - wait 24 hours and refill the system and motor on. Some people have also added a setscrew.

 

Thanks for the insights...its now in the shop awaiting someone with way more skills than I'll ever have to diagnose it. Will keep you posted on what comes out. I like to track trends and root causes, hoping it might help someone else in the future.

 

Sounds from the description that this may indeed be the coolant bridge problem where the hose dislodges from the bridge itself. The new units actually screw on to fix the "known" problem, but I'm told that you need to drop the engine to access it ..... best of luck with the diagnosis and the fix, and please keep us all posted!

 

That's officially called the "Coolant Guide Tube" - and there is no mention of R&R of it in the 958 factory manual or all-data. On my '06 S it was possible to R&R it without engine removal. I believe on the 958 series V8's - it may be possible with the engine in place provided you remove the high pressure fuel pump and the vacuum pump - both driven by the camshaft rear ends.

 

Just got the word back from the shop...while being somewhat vague, they said that one of the coolant pipes (under the intake manifold) had disconnected, and they replaced some items/resealed the system. It's been pressure tested and is being test driven for a few cycles to make sure that there are no leaks under thermal loading. Sorry I don't have pictures to share. I'll post up what's on the invoice when I get it tomorrow.


No need to drop the engine for this repair (Phew!), the car has 80K on it so it's out of warranty, total cost to fix is approximately $550 at the dealer.


Thanks for the replies and assistance. I'd love to get access to a database highlighting "known" problems that forum members are experiencing with the different Cayenne models...

 

I'll be quite interested in seeing what parts were involved.

As far as a database - certainly doable on-line - but would require someone to moderate it so same problems aren't listed under different listings. Up for the job?

 

The Cayenne is back home (yay!), and this is what the repair invoice said: "Check out and repair loose coolant pipe, fill and bleed cooling system, leak check." Sadly, that is it. I would have loved to had pictures to post, but then that might encourage someone to fix it themselves rather than the dealer....


"As far as a database - certainly doable on-line - but would require someone to moderate it so same problems aren't listed under different listings. Up for the job?"


Don, I would actually be interested in doing that...I'm NOT a computer wiz, but I do something similar for about 30 Army helicopters. When our pilots have a "Precautionary Landing" due to a malfunction, I track the details to see if certain tail numbers have recurring issues. Not sure I'd be the right guy for the job, but I certainly would be happy to help!
---Rob

 

Can you do us all a favor and bug the dealer a bit to find out what coolant pipe came loose? As you noted it might well help someone DIY if this happened to them.Let me think a bit about how to best do it - and especially what answers we're seeking (the only way to design a database is to ask what the answers have to include - then you know what has to be imputed..)

I'll be in touch.

 

"Can you do us all a favor and bug the dealer a bit to find out what coolant pipe came loose?"


I'll go in early tomorrow and ask for sure! PM sent on the other topic.