I have a 99 c2. I just replaced the water pump, tstat, and coolant tank with the updated black cap. I am getting a flashing coolant light only when it goes a little past the 180 mark. It will reach 200 F. At that time I usually park it but it never goes past 200 F. When running and when it's shut off the tank is filled but the pressure release valve is wide open. After it had cooled the valve seated back into the closed position. I then checked the levels again and still perfect. I opened the valve by flipping the lever up and drove it for a bit to see if it would burp it but once the light started flashing and parked it to look at the tank and the valve was popped open by itself. As in the lever was layed down while the valve was full open.

Any suggestions would be appreciated

 

U-View 55000 Air Lift Vacuum and Cooling System Tester and Refiller

 

The flashing light is trying to tell you that you have air in the system. When I bought my car (it was from the south) the antifreeze wasn't strong enough to withstand the cold where I live. I pumped some of the existing solution out and added straight A/F until I got the freeze temp I needed. For a while after that I'd get the flashing light occasionally (usually during brisk driving). It eventually worked it's way out of the system.

 

Did your temps reach 215 F?
I ordered that tool. Thanks btw
I requested to wright motorsports to do a coolant flush. Recieved it back and noticed the light flashing above 180 F. The overflow tank was also empty when I checked it. They then indicted to me that it is said not safe to do a pressure flush on the watercooled engines so they do a drain and fill.
Not sure on how true that is.

 

Sometimes you can rid yourself of the bubbles if you park the car on a steep street (or jack the *** end of the car up) and the bubbles may migrate out of the system. be careful if you jack the car up.

 

let it stand in the garage with the coolant cap off and let the car slowly warm up to as high as it wants. Maybe 20 minutes or more. See does that burp the system. Stand at the back and watch the level. Top it up with hot water if it drops. Measure the amount so you can add collant to the correct level. If that doesnt solve it, I would drop a bucket of what evers in there out of the system drain plug when cold, then start the engine and top up from the same bucket as the engine is ticking over. That may find the unwanted air. Anythings worth a try and it can't damage anything if its done correctly. I would also put the heating on full bore while you are doing this to get the system circulating properly. anyway good luck with your efforts to solve the problem.

If that doesnt work then I am pretty certain that 'White99C2' posting will work for you. Again.. Good luck.

 

I never had any high temps when the light started flashing. I think you probably have more air trapped in the system than I did and thus the cooling capacity is reduced. I noticed a couple of comments about raising the back of the car which would seem to make sense. Good suggestions there too about adding hot water only to the running engine. I once (a long time ago) cracked a head adding cold water to a hot engine.
Good luck with this issue.

 

I recently replaced my water pump as well. I found that the procedure in the shop manual worked really well to get the air out. Basically you run the car for 10 minutes at 2500 rpms. Then run it for another 5 minutes at 2500 rpms and every 30 seconds blip the throttle to 5000 rpms. I didn't have to add anything after the car warmed up and ran for 10 minutes but had to add about a quart after the 5 minutes of blipping the throttle.

 

I really don't think my neighbors will like that to much lol

 

Lift the pressure relief valve up, it will stay straight up and take the car on a nice 15 or 20 minute drive. Let the car cool down and top it off. It worked on my car.

 

I forgot to mention that you need a compressor to use it.
I have used mine on a Subaru and Mercedes ML350. Not on the Porsche yet.

 

Ill probably tackle tbe job next week since the derby is this weekend B)