dschauer

I purchased a 2018 911 T in May. Just love the car but got a STOP ENGINE IMMEDIATELY warning while driving in very rural area last Sunday. Roadside Assist assigned to towing company who was unable to pickup car due to low clearance. Once engine cooled enough found that coolant level was showing minimum. Had to have friend pickup coolant, added 3L, (now know I should have just added distilled water since coolant I added was not Porsche spec) so that I could limp it home. From my home Roadside Assist was able to get towing company to pickup car. Unbelievable disappointed that such a major problem could occur on a brand new car...and very concerned about any residual damage to car that obviously has been operating with low or no coolant. I have a lift where I keep the car and have not had any signs of leakage on car or garage floor. Any ideas what could cause this? Should I be worried about future performance/reliability?

LexVan

Are you saying the car took in 3 litres of coolant without any visible leak? That's a lot.

And if you used the wrong coolant, make sure your dealership does a full coolant flush. You should be expected to pay for that, since you added the wrong liquid. Maybe they will warranty for you, but don't expect it.

As for residual damage, don't worry about it. Sounds like you got the car shut down soon enough, and don't forget, more than 50% of your cooling comes from the +8 litres of synthetic oil.

Jim M.

Had a leak in mine. You could only see it after shutting it down after a drive. Just running it in the morning it wouldn't leak. Turned out is was the coolant overflow tank, changed under warranty.

dschauer

Thank you for your assurance on future performance and reliability and agree that it seems crazy that there are no signs of a leak with it being down 3 liters. Told dealer to do a full flush and explained that I didn't believe there was any other options since Roadside Assist wasn't able to locate a towing company willing to load the car with such low clearance in the very rural area where I had to stop (I was getting passed by more that one horse and buggy - wish I was kidding). Will see if they charge me.

dschauer

Hope it is the overflow tank and nothing more significant. Will post what I find out. Thank you for your help.

LexVan

My only guess, if it was truly down 3L, was the car was underfilled at the factory and the dealership also missed it during PDI. But, you already drove 1,600 miles, so it's really strange to surface only now. I bet they find a leak someplace.

subshooter

I had this happen in my 981 at 2500 miles or so. Dealer said it was an air bubble in the coolant system from initial fill. The factory fills the system quickly and sometimes they get air bubbles in them that for some reason is revealed 1000s of miles later. That's what he said anyway. I got it refilled and never had a problem since. Now at 41k miles.

3L is a big air bubble though.

LexVan

I hope you put the 3 L in the blue cap, and not the yellow cap.

Ok, now I'm just messing with ya.

Not the blue cap in the front.

dschauer

Air bubble does sound unlikely except for the fact that there is no evidence of leaking anywhere in the garage or that was visible when up on the lift.

aCayenneFan

The non-obvious (leaks that don't have telltale dried coolant in the area of the leak) coolant leaks can be a PITA to find. Especially if the leak only appears when the engine is hot. If it really is a 3L deficit, my bet is one (or both) front radiator(s) is leaking. But it could also be the expansion tank, as Lex mentioned.

911-TOUR

I just had this happen on our Land Rover after an annual service that included a coolant flush. Car drove normally for 400 miles, then sat for 3 weeks while we were on vacation, then no coolant on startup after we got home. The reservoir was completely empty. The shop suggested that an air bubble in the system caused an underfill after flush. Contacted LR and the official procedure is to wait 4 hours and check the levels after warming the coolant to 165F or better.

Not sure I entirely believe that - doesn't seem to make sense - why didn't the level read low after starting up once I brought the car home and it sat overnight and started it up? But another datapoint. I refilled, and 4 weeks later the levels are still normal, so no leak. Bizzaro.

cheers!

Bradley Scott

My car is on the way to the dealer today for coolant leak (we put in containers of coolant about 4 weeks ago - and the reservoir is now empty).

dschauer

Dealer called yesterday to say that it is a water pump bearing failure and that they just happened to have one available (obviously I'm not the only one with this problem) so it is being installed. The more I dwell on this the more I want to know what possible damage or excessive wear occurred as a result.

Assume the water pump likely never worked properly therefore for 1,500 miles the coolant didn’t circulate properly. There were no leaks (never saw one drop on garage floor or while on lift) so the 3 liters of coolant likely boiled off. This would seem to explain why there was no prior warning (only warning was the Stop Engine Immediately signal) assuming the coolant temperature sensor must be on the ‘cold’ side of the water pump.

So question is how could the coolant boil off in a pressurized system and if it wasn’t pressurized because the pump didn’t work how hot did the coolant get to cause it to boil off? How can we ever know how hot the engine actually got. Assume that engine oil would have been an fairly effective coolant. Should the oil be changed and tested to see if it degraded because of heat?

Obviously the cooling system is there for a reason so wouldn’t the lack of cooling likely cause some damage?

Am I over thinking this? Should I be concerned?

Pep!RRRR

arter

The good news is that the oil system is what cools the car and turbos and then transfers heat to the water system.
So if the oil temp didnt get too high ( and alarm), likely no damage occurred.