HELP Needed 996 overheats

Hello, car is a 2001 C4 manual, has 55k miles, and has new water pump and thermostat installed about 120 miles ago. No water leaks, fans work well, but water gauge passes mid line and goes towards red if I dont switch it off. When the temperature is that high, the oil pressure wont exceed 3,5 bar at 5000rpm. There is no water in the oil, or vice versa. Could it be a head gasket ? Any advice would be greatly appreciated[/QUOTE]

Have you checked coolant level? After opening the system, it take some time for all the air that is admitted to bleed out. You would need to top off the coolant level and monitor for several driving cycles.

Done that three times... No more colant needed. There is also no leaking.

Might be a blockage of coolant flow? How did the waterpump fail? Was there evidence of a broken impeller? Could there be debris from the damaged pump somewhere in the system impeding coolant flow? Check thermostat installation?

Perhaps new thermostat is defective? You could remove and test the thermostat.

If you didn't do a mechanical bleed then you can still have air in the system which would cause overeheating. try driving with the heater on high, i know it's hot in nc but if you can stand it it may work. keep us posted.

Is the cars' computer designed to shut down the engine's rpm's if the temperature exceeds a given threshold? I know my big outboard motor will reduce the engine's rpm's if the oil pressure drops below a certain level as a mechanical safety margin as well as an indicator for the driver that something is amiss..

Guys the motor was bled with the right procedure (opening the valve on the coolant reservoir, and putting the heater on) Fans are working as they should. The therostat was changed by a garage, so was the water pump. There was nothing wrong with the pump, just changed due to mileage. Since then the car overheats... Guess it is a blown gasket. Car also has low oil pressure when this hot

I would check the water pump and thermostat installation.

I would take it back to the 'mechanic' that replaced this stuff. Dont you think its a little too coincidental?

[/QUOTE] Does it actually go to red or does it just reach to about, lets say, 3/4s to the right? By your avatar you are used to cold weather and now maybe you are driving in warm weather? It is normal for the needle to go to about 5/8s or so to the right on hot days. Unless it actually makes it to red and flashs the warning light you are not overheating. You said you have low oil pressure. My car can get as low as .8-.9 bar at idle when the temps reach 100 degrees fahrenheit, totally normal.

I agree if the car wasn't overheating prior to the water pump/thermostat service then the install was done incorrectly. I wouldnt start jumping to conclusions about a damaged head gasket just yet. It could be something as simple as the thermostat being installed backwards which I have seen. Bring it back to them and have them double check the install.

Does it actually go to red or does it just reach to about, lets say, 3/4s to the right? By your avatar you are used to cold weather and now maybe you are driving in warm weather? It is normal for the needle to go to about 5/8s or so to the right on hot days. Unless it actually makes it to red and flashs the warning light you are not overheating. You said you have low oil pressure. My car can get as low as .8-.9 bar at idle when the temps reach 100 degrees fahrenheit, totally normal.[/QUOTE] +1 above, I am in AZ - 115 degree days, stop and go, and my car often goes over the mid line, then the fan will kick in and hover around the middle line. Once, the car went to almost 3/4s of temp guage and the AC shut off and blew hot air until the fans kicked on and started to decrease the temp. to normal levels. Has something like this happened?

Michael , i have same problem right now with my 2000 C2 , i don't even drive in hot climate .I am from Seattle ,but if i stock in traffic ,them car start geting hot .My gauge don't get to the red spot,but it will move to the right ,so i know it is too hot for car .I did manual switch mod ,so i can turn my fans manually .It is helps ,but it is not proper way to fix a problem .And I did ,same as you , i drove with open valve ,nothing helps .

Yeah its frustrating some times, like someone is holding a lighter closer and closer to your woman until she is about to burn.... I have been having much better results since my coolant flush but still on the way home it gets hot. At last check, yesterday it was up to 117 degrees c in the coolant. That is hot my friend....

Head gasket blown. Happened because the previous garage that had changed the pump didn't do a proper bleeding of the system, and car had overheated 2 or 3 times I live in Athens, and the car that overheats is not mine. The car on the avatar is my 1st 996 C4S drifting in a parking lot at the Austrian Alps. No worries about high temperatures there. Here we had 47C last week, which was an al time record since 1916......That was darn HOT!!!!

I have no doubt that some of these cars run hot, but I think a lot of worry stems from the fact that most people haven't had a car with a real temperature gage for many, many years. The 'gage' you see in your Honda or Pontiac is little more than an idiot light disguised as a gage to look sporty. Even in my Rover, that needle stays planted right in the middle of the 'gage' no matter the season, the driving conditions, or anything else. There can be a blast furnace coming off that ol' V8, and it can be reeking of coolant, but that gage keeps insisting that nothing has changed. That's because it's not a real gage. The 996's is.

That is hot. The hottest I have seen on my 3.4L is 106C. Have you cleaned your radiators recently? I have found it necessary to do this every 12 mo's or so. You must remove the front bumper cover and the radiator shrouds. Then you can pull the AC condensor away from the radiator and clean between them. You would be amazed how much crap finds its way between the two.

You should consider upgrading to a 3rd radiator. I live in Texas and upgraded mine before last summer. I notice it runs 10-15 degrees cooler when tracking on hot days with the 3rd radiator.

Here's a basic suggestion. Take a look at the ac condensors and see if a lot of the cooling fins are squished flat. A lot of debris (rocks etc) gets in there and it's moving at whatever speed you were doing at the time and the aluminum of the fins is quite soft and deforms easily. On mine I would say about a quarter to a third on each side were squished enough to more or less stop airflow and the rad is right behind the condensor of course. No air flow equals no cooling and that's a big chunck of the radiators not doing anything. On mine I would find that when stuck in traffic when the temps were high the engine would get hot enough that the computer would turn off the AC until the temp came down again. I spent a couple of hours last weekend straightening out most all of the fins and also blew a bunch of dust and other junk out with an air line. No super hot days or traffic so far to check if it's resolved the issue but I have a feeling it probably has. Colin

Ouch. Is the shop stepping up and taking some responsibility for the blown gasket? Hopefully so. Best of luck, Michael

You can ad a Factory 3rd radiator from the Euro X51 (manual only) www.carnewal.com