Goatcayenne

Hey all. Long time on the forum but never posted. I’ve having the an issue with my 2014 cayenne diesel 77k miles.

A week ago I got a low coolant warning starting it up in the afternoon after it had been sitting for 4 days. I checked for leaks, could find any. Checked the expansion tank and it was missing about 10 ounces of coolant. Filled it and the warning went away.

Took the car for a drive and no problems. Popped the hood open and could smell the sweet smell of burning coolant. I used a clean funnel so nothing dripped. I drove it for 3 days in a row and no problems, just the smell. I took it to my indy for an oil change and to check out the issue. He couldn’t find any leak. They did a pressure test and there were no issues. Visual inspection found nothing. Oil was clear. I had them do a complete coolant flush and refill the coolant.

I received the car back on Tuesday. And it sat for 3 days. This morning I started it up and got the warning again. This time nearly a half jug of coolant was short. I filled it back to just over min and took it over to the Indy again. I had called Porsche and can’t get an appointment for two weeks. I’m hoping the Indy can figure it out.

Now one issue i discovered is that the vehicle will get to operating temp in about 3 minutes of driving from cold. Operating temp holds at 200F. Before it would take about 10-15 min of normal driving.

does anyone have any insight. I know there is a leak but no
puddles or burned coolant residue. Any help is appreciated.

BrewDude

If you do have a leak, the undertrays may be absorbing any coolant lost so might explain why you're not seeing any drips. Check the radiator end caps as they are plastic and mated to the metal of the radiator core. They have been known to leak and coolant will crystallize; you'll never see the leak hit the ground.

It may also be that the cooling system has air in in it and it's just burping it off, to which adding coolant will be necessary. However, for a system to be a 1/2 gallon of coolant low...that's a lot of air displacing fluid.

Goatcayenne

I would think a pressure check would have ruled out the caps right? Prior to the flush it still was losing coolant, so wouldn’t that rule out air as it’s never been flushed before.

B.Kish

As a point of reference, my CD water warmed from cold to an indicated 200 degrees in 3:28 today with an ambient of 47 and speed of approx 40-45 mph. The oil won’t reach operating temps (150+) for almost 13 mins in the same scenario.

Spyerx

Expansion tank leak?

paver

I have a 2013 Touareg TDI which is the same motor as your Cayenne. I have a coolant leak that never drips onto the garage floor. Yet I have to add coolant on a regular basis. The touaregs are know to leak from a vacuum controlled valve that is on top of the engine between the cylinder banks. The coolant puddles in there and burns off so never shows up on the ground. The valve is under the intake manifold.

dollarlongnecks

Is this the part you are talking about?

I've been having this same issue for over a year now. Went round and round with my local dealership who claimed there was no leak. Finally thought I found it with an expansion tank that appeared to be leaking from underneath, and got another nearby dealership to fix that under warranty. But it's back now, and what I thought was a leaky tank was likely just coolant blowing past the cap, which empties underneath the tank. I replaced the cap as well, but when I remove it I can see residue underneath, so I know some coolant has been escaping there - but that just makes me think it's running too hot or at too high of a pressure, which isn't good.

paver

this is it. The intake manifold and other parts have to come off to get to it or even see it.

dollarlongnecks

Grrrrrr.

STALKER99

I had a long term problem that was hard to find. Turns out the leak was basically somewhat in the middle of the V of the motor. The coolant leaks into a tray and doesn’t drip so hard to spot. Apparently it’s not uncommon.

dollarlongnecks

Do you think this - or the other mention of a leak into the V of the engine - could be seen with a lighted inspection camera?

I'd rather not pull half the engine apart just to "see" if the leak is there...

Also, I know there are fluorescent dyes for oil leak location, so I'd imagine they are available for coolant leaks as well - does anyone have experience with something like that?

paver

I'd be willing to bet this is the same leak stalker99 is talking about. I don't know if there is an inspection camera that would snake it's way in there. I was barely able to see the puddle of coolant w/o taking anything off other than the press-on plastic cover.

dollarlongnecks

@paver, any info on what this part is called, numbered, etc? I spent last night looking through diagrams and couldn't be sure about locating it.

paver

the VW # is 059 121 737 AM

I'm not sure how that crosses over to Porsche. Is there a PET for Cayennes?

dollarlongnecks

I unfamiliar with the PET term, but after some searching I'm guessing they are parts diagrams?

I've been looking here: https://nemigaparts.com/cat_spares/pet/porsche/92a/37/