991.2 keeps randomly overheating
11-20-2023, 08:15 PM
#17
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Thread Starter
Well it just did it again. Sigh. Sitting here on the side of the road. Wont settle down again - i get a mile or two and off it goes again.
i checked the coolant its full and obviously given i was able to safely, means the wider cooling system was not hot at all - its the thermostat is not opening.
Do the cov valves control the thermostat opening? i mean its got a brand new thermostat in it...
i checked the coolant its full and obviously given i was able to safely, means the wider cooling system was not hot at all - its the thermostat is not opening.
Do the cov valves control the thermostat opening? i mean its got a brand new thermostat in it...
11-20-2023, 09:12 PM
#18
UR car sounds like mine, same issues, new thermostat and it goes bonkers, no rhyme or reason..if U get it fixed before me, please post cause.. i made appt at indy but still 2 weeks to wait.
11-21-2023, 12:02 PM
#20
The .2 has the COV controlled water pump. The .1 has a COV controlled coolant bypass. All features designed to heat up engine sooner. Should fail safe, but if the mechanism themselves fail could overheat.
What does the COV up by the radiators do?
You guys check the radiators and verified there’s no road debris blocking airflow?
What does the COV up by the radiators do?
You guys check the radiators and verified there’s no road debris blocking airflow?
11-21-2023, 08:57 PM
#21
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Thread Starter
The .2 has the COV controlled water pump. The .1 has a COV controlled coolant bypass. All features designed to heat up engine sooner. Should fail safe, but if the mechanism themselves fail could overheat.
What does the COV up by the radiators do?
You guys check the radiators and verified there’s no road debris blocking airflow?
What does the COV up by the radiators do?
You guys check the radiators and verified there’s no road debris blocking airflow?
my next step is the COV valve block. Its all thats left aside from taking off the tune i have on it.
11-21-2023, 09:52 PM
#22
Rennlist Member
Sounds to me like there is coolant in the water pump vacuum lines. If you read the waterpump failure thread, you'll see that the pump leaks coolant into the vacuum control lines. After I had my first pump replaced I had a couple of overheating issues similarly to yours. The dealership 'burped' the coolant to get any air out. I got the car back and had the same overheating issue. They found the coolant in the lines and replaced the control valve block and all has been good. I think they extended the warranty on the pump and controllers.
11-21-2023, 11:02 PM
#23
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Thread Starter
Sounds to me like there is coolant in the water pump vacuum lines. If you read the waterpump failure thread, you'll see that the pump leaks coolant into the vacuum control lines. After I had my first pump replaced I had a couple of overheating issues similarly to yours. The dealership 'burped' the coolant to get any air out. I got the car back and had the same overheating issue. They found the coolant in the lines and replaced the control valve block and all has been good. I think they extended the warranty on the pump and controllers.
But after the second time this occurred, I took it to Newport Porsche to get the water pump looked at, suspecting that was it. They told me that my pump had already been replaced and they checked for coolant in the lines. It was all clear. They blamed the overheating on the tune I have in it, did literally nothing else to help diagnose and that was it - case closed to them. Never mind the fact the tune has been on there for years now.
The only thing i have no done yet is the COV valve block. Given the spaghetti mess of vacuum lines under the bumper (what a disaster of a design) its possible that one has kinked and maybe thats it too? Idk.
But it seems the logical next step.
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c1pher (11-22-2023)
11-29-2023, 01:34 AM
#25
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Thread Starter
11-29-2023, 03:11 AM
#26
Rennlist Member
It’s probably not the tune at all. Coolant leaked from water pump into COV block and vacuum lines. Dealer should replace water pump, COV block, valves, lines, and vacuum pump. Many have had this happen.
They may have checked and supposedly seen that lines are clear, but if there was a leak the dried up coolant mucks up the COV block and valves. Still most likely culprit despite what they are saying.
Good luck!
They may have checked and supposedly seen that lines are clear, but if there was a leak the dried up coolant mucks up the COV block and valves. Still most likely culprit despite what they are saying.
Good luck!
Last edited by devtec; 11-29-2023 at 03:13 AM.
11-29-2023, 09:59 AM
#28
If your adding coolant where is it going? Has Porsche tested the coolant system for exhaust gases? A blown head gasket would cause the coolant system to become entrained with air, think a very small leak. Water pump is vacuum operated on 991.2, if you want there is a 90 degree vacuum hose right below the water pump. Unplug it, does coolant pour out, there should be zero. This is a solvable problem, it appears the super qualified special citizen porshe technicians missed a programming session......
12-05-2023, 02:17 PM
#30
towed car to dealer week ago,they called and are going to replace waterpump again(2nd replacement) and the valve block, etc..no mention of $$$ so Im guessing that 10 year warranty is kicking in and they are going to have it delivered to my house which is 1 hour away. Hope that cures it.
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polobai (12-06-2023)