Pleased to find this place. Can't get onto 968.net and used to find that place a mine of information.

My 1994 968 coupe has started overheating. The coolant level is slightly low but more noticable, the fans don't seem to come on. It overheats at rest and on motorway runs at 3000-4000rpm and 80-90mph. Both fan fuses seem ok. Could it be the relay. I know these are expensive to replace unless you are certain that is the problem. What's the most sensible way to test the simple things first.

Many thanks

Matt

 

thanks

 

Ray let .net shrivel up and die, he's now married and enjoying life. Welcome to Rennlist! You'll recognize a lot of .netters around here.

 

The thermo switch frequently goes bad. It's screwed into the radiator and is reasonably cheap and easy to replace. If the fans go on and off it's not the problem though and only one possible thing if the fans don't go on at all.
hope this helps

 

thanks guys.

Car still overheating but driving with the heating on keeps the temp just below top marker. Interestingly, when I stopped the engine, at least one fan was working and running.

Any more suggestions.

Thanks again

 

Try bleeding the cooling system.
Some of the air pockets are very stubourn.

 

have you checked the fuses? when the fans start to go (bind) you can blow fuses.

 

Go to Clarks Garage and follow the troubleshooting guide in the Garage Shop Manual link, it will get you covered in short order. While its written for the 944/951 crowd, most of the stuff listed there will apply to 968's as well.

Regards,

 

Check to see if the radiator itself is hot... If not, could be T-stat or failed WP. I believe that the fans only run when the radiator temp is hot enough to cause demand.

 

Thanks guys. Can anyone tell me how to change the thermoswitch? Where to find etc. Part number etc

 

matt feel free to give me a call 866-944-7883 ask for steve

 

Matt- Been there recently I posted a write up you can find it under notthd posted not too long ago.I'll add some of it here.

SHORT LIST
**1st- Bleed the system
**with car running hit AC button- both fans should come on- if not, fuses or relays.
**Fuses relays bad make sure the fans spin free- could be bearings blowing causing the blow
**If all good there and fans come on w/ac button but not when hot- Thermo switch in drivers side top of radiator may be bad- I HAVE ONE YOU CAN BORROW TO TROUBLESHOOT IF YOU LIKE!!!
**from there is the radiator hot? if not check the thermostat, if it is not hot but the temp gauge is overheating it might be the WP,
**lastly run the car with the AC button pushed if it still overheats the car is not moving coolant because of an air bubble, obstruction (thermotat not opening) or failed WP impeller.
- what am ia forgetting guys...?



Now for the long version - from my old post, I hope this helps and is not too boring for yall.- Cheers, Mike

So I wandered to the garage last night and continued to live in denial that my waterpump impeller is shot and thought maybe it's something else.

Bled the system, and mounted temperature sensors in the block and in the radiator to see EXACTLY WTF is going on. Since the block seems like it is getting hot but the system has no pressure and the fans do not come on I had to know. The results in my mind say waterpump. Started out at low temp with the radiator at 65 degrees and the block 63F. As I ran the car the block slowly started to increase and the radiator never moved. After 5 mins or as the block crossed over into the 120 degrees range the radiator jumped to 74.7F. I assume the thermostat opened. From there the rad temp never got higher than 74F as the block temp ran up to redline. just below 190 I shut the car down. Guess the temp gauge in the dash is working...
Pulled both sensors and they read within a degree of each other- experiment over

The car is not moving coolant- a moment of silence please. What pumps have you guys used. I replaced one in the 951 but never in the cab. Ideas or experiences welcomed. Other while I am in there ideas also ? -

Cheers, Mike








Another post --When the pump is working properly the flow is noticeably higher than it is now, the fans do work when you put on the AC switch, the thermo is new as is the fan sensor. Since the temp never gets above 74 degrees in the radiator they never come on. Thought it might have been the WP or thermo initially because even with the fans manually turned on full they did not cool the motor.

Good ideas though... Cheers Mike

 

Mike, any chance you could post this information in a seperate post as well so it's easy for people to find it.
So far we have been using this format:
DIY: and then you put down the what the DIY is about here.
Example: DIY: Bleeding coolant in a 968
Thanks in advance. We appreciate the help.
Raj