High Coolant Consumption
 

I have a 2015 Cayenne S with about 30k miles. The red warning message came up telling me coolant was low couple of days ago. I looked at the coolant reservoir and did see that the coolant level was way below the MIN line. Brought it into the dealer and they weren't able to find any leaks. So, they just refilled it and sent me on my way. All they said was to monitor it closely to see if the level goes back down soon before taking it seriously. It just seems odd to me that the coolant would be so low after only 30k. I've owned countless vehicles and never encountered this issue at such low mileage (unless there was a leak). Has anyone run into this same issue on their Cayenne?

-porschedad_73

I don't smell any coolant nor do I see any signs of leakage on my garage floor. We did encounter historic lows last week due to the polar vortex so now I'm wondering whether that had something to do with it but then I would still expect to see a pool of coolant on the floor. Anyway, thanks for the response. I'll keep a close eye on the issue and report back if the siutation worsens.

On 2 occasions in the last few weeks, after particularly cold days, I got the message to add coolant right when I started the car. The 2nd time my temp gauge immediately went all the way up and flashed red - even though the car was ice cold and had just been started. I turned it off, turned it back on, and had no warning message or elevated temps for the rest of the morning. I went to the dealership after breakfast and they topped it off, noting very little had to be added. The tech did say he suspected a sticky sensor due to the cold and that they saw no leaks anywhere. I have had no issues or warnings since.

This is Porsche's way of getting your attention that the coolant is low. Has nothing to do with the actual engine temperature. It's very annoying....

A FWIW - coolant is not a consumable unless something is WRONG. If your car is using coolant, it's either leaking it somewhere or leaking it into the engine (cylinder, oil passages, etc.) - in any case - the cause should be found. Just topping it off is a good way to make certain at some future time, in the most inconvenient location at the most inconvenient time - there will be a massive coolant failure stranding you. A dealer employee who tells you it's normal and sends you on your way is both lazy and stupid. There are known leak points on the 958 Cayenne. On the V8 engines there is a fitting at the rear of the engine that's known for leaking, and at the front of the engine the two pipes going into the thermostat housing are known leak points. In both cases it's because Porsche used GLUE to hold the pipes in. The glue eventually fails. Failure starts out as leaking, and eventually evolves into a total failure and massive coolant loss. Porsche has redesigned the parts involved so the plumbing uses mechanical fasteners to hold things together - not glue.

There are threads on both subjects - and some DIY writeups in the DIY subforum. I'd suggest looking for them and becoming informed on the subject. It seems Porsche was much better at air-cooling engines rather than liquid cooling them.

Thanks deilenberger. I certainly don't wish the total failure would happen to mine since my wife uses it mostly to haul the kids around town. The last thing I want is for them to get stranded somewhere. It's also odd to me that the dealer would just brush me off like that. I never have a good feeling about them but it's the closest one to where I live. Another dealership is an hour away. That's why I wanted to get second opinion from the helpful folks here. I tried to find other related threads before starting this one but wasn't able to. Since my CS is a CPO, I definitely don't want to perform any DIYs like this to jeopardize the warranty. The more helpful feedback I get from y'all, the more informed I am to go discuss with the dealership next time this happens. I, too, am quite baffled about this. Mine is not V8 so wonder if the design is different? Anyway, I'll have to keep a close eye on this one. Quite annoying having to worry about this and wonder if it will fail if I take it on a long trip.

The point is that the cooling system is a closed environment and if more coolant needs to be added then, although the dealer may be blowing it off as normal, the missing coolant is escaping somehow. If you're not smelling it then it's either dripping straight down to the pans and evaporating, leaking externally but not onto anything hot enough to cause the telltale smell or it's leaking internally. I'd suggest dropping the pans to look at them for signs of coolant as that will help with the search. The other thing to get is an endoscope that hooks up to a smartphone to allow searching at the rear of the engine for signs of a drip that doesn't make it all the way down. Also look at the water pump as mine had a drip at some point before I bought the vehicle as it had the remnants of evaporated coolant. The next spot to search is the area of the overflow tank as those connections have been know to leak, especially in colder weather. If you still can't find it then it might be worthwhile to have an oil analysis done at the next oil change for any evidence of coolant in the oil.

I had a similar experience. Coolant warning came on, topped it off, and brought it to the dealer. They pressure tested it and it held pressure. I told them it's impossible for the coolant level to drop if there's no leak, so they held it over night to let it get good and cold and did another pressure test in the morning. Still no issues. As frustrating as it was, it was also hard to argue with the result.

The only other thing I could think of would be if parts of the system are isolated when the engine is off? I.e., they would not get pressurized during their test and be missed? Or something only leaks when it's hot?

Entirely possible for there to be hot only or cold only leaks.. and those probably are difficult to replicate, but there should be clues, especially with the encrustations that Porsche coolant leaves behind when there is any leak.. it takes a good eye and some experience to find the leak, but there is a leak..

FWIW - I spent close to a year chasing one on my '06 CS - finally found trails of coolant deposits running down the side of the torque-converter housing (aka bell-housing) - I documented it with photos, printed out the photos and handed them to the service manager and said "Fix this.." - took them 3 days - they ended up replacing the coolant bridge on the back of the engine. Leak was gone.

Absolutely. To the OP, my experience was this.....only in extremely cold periods of weather (20s and below), and only when the vehicle had been sitting unused for a while (stone cold), I would get a small coolant puddle on the garage floor on the right/passenger's side near the front wheel. First trip to the dealer resulted in 'no leak/problem found'. A second trip the following year for the same issue resulted in a problem found with the coolant reservoir and some associated hoses and fittings which were replaced. I never experienced the issue again up until I traded it in. So as deilenberger and others have mentioned, it can very well be a temperature extreme issue that can be tough to identify. At least in my case there was a small visible puddle to start with.

I have the same on my 15 CS.. i can smell it, but cant find any trails... dealer smelled it as well on drop off, but cant find it - level was a bit low and topped up. I need to take off all the covers and poke around and do a end of warranty visit.

Wish this thing was air-cooled :P

phil.