I have a 2012 c2 991 that is overheating. I think it is 80 % likely the water pump. What happens, it gets to the usual 190ish and then all of a sudden 210 and climbing. It has water/coolant in it and cant see any obvious leaks. The biggest thing that makes me think water isnt moving is, when it gets hot the radiators arent even warm. Should i replace the water pump or does anyone have advice or experience that would lead you to something else?

 

One of your solenoids could be bad, which stops the radiator fans from working.

 

The only argument against this is that the radiators would have hot water flowing through them and be warmer that room temperature. I reached out to a contact at the local Porsche dealer and he thinks it is 2 possible things.

1. coolant got too low and developed an air pocket
2. the thermostat could be Blocking flow to the radiators.

 

17 CS when water gets close to 220 i put it in Sport and drops 20 degrees in a few miles and it is the shop now for water pump;}

 

Update- so i talked with a Customer who was managing a Porsche service department up until recently. He suggested air had gotten in the system or thermostat since it wasn't getting flow up to the radiators. One method they can use is to fill and allow it to sit overnight and settle into the area's where there is air. That seemed to work and a day later the radiators were working and I drove it for a bit. The oil temp got up to 210 uphill and when i was going downhill it cooled back under 200. The coolant gauge only showed the typical 190 or whatever the default is. This would lead me to believe that the coolant system is working now.

My only concern now is how was the coolant low in the first place. I have only had the car a short time and we are in full summer swing with temps from 90-105 F but there are no signs of leaks. I can admit that I hadn't checked the level in the past so It could have been low to begin with. I can't find any talk of head gaskets on 991 going bad and I haven't seen any white smoke out of the exhaust. I could do an oil change and see what that looks like.

 

I think i figured out my slow leak with no moisture under. I lose a couple ounces of fluid if i drive for 10-15 minutes. There is a chip at the edge of the inside of the reservoir opening that would possibly allow pressure to escape and go out the release hole. Im 98% sure. Can someone confirm there is no chip here.

 

That's a really small chip and I think its probably inconsequential. If you are concerned with cap leakage replace the O-ring or cap itself. Also, since the car is new to you have you checked the radiators for blockage? 991's are famous for leaf and debris blockage, take a leaf blower or air compressor and blow that area out on each front bumper intake.

 

The front radiators are very clear i checked that right when i purchased the vehicle and initially cleaned it. I took the rear spoiler off and i can see the overflow drain hose is letting a little fluid out. See picture. This would lead me to believe that this is the source of the leak . Can someone check a 991.1 and confirm there is no chip/ notch there? If there is then i will replace the cap. If not i have to buy the overflow tank.

 

Also, what o ring are you mentioning

 

Maybe your car is overpressurizing the cooling system. What sensor controls that input? If you are saying that your overfill is consistently discharging coolant then this might be the issue.


You can buy a coolant vacuum system from a place like ECSTuning.com. You can pull a vacuum on the system. You will remove coolant and the discharge hose will almost create a wonderful coolant aerosol. Then you can use the same tool to pull coolant into the system.

There is a purge valve underneath somewhere that allow the system to purge air out but this should be closed. Maybe check to see if your is open for some reason. This would make sense since you are losing coolant and the car attempts to pressurize.