Stuttgart996

Okay so my car is a 1986 951 and it usually runs at the quarter mark when it warms up and stays there. Recently when i am do stop and go driving it will go up to the middle and come close to the 3/4 mark. It has never gone past the 3/4 but this still worries me. Anyone have any suggestions on what to do?
I am running these upgrades:
Piggyback SMT
Autothority Chips
Tial Wastegate
Lindsey Exhaust
and 14 lbs of boost

Thanks
Any comments or suggestions would be greatly appreciated.

lart951

cooling fans not working, cooling fans relay malfuntioning, air in your cooling system, Thermostat not working, blown head gasket.

Ian Carr

probably air in your cooling system, or you just need to flush the system (anti-freeze does get old ). Could be your fans aswell.

Stuttgart996

okay i flushed the system and put new fluid in about 3 days ago and still doing it, also opened the screw to bleed the air out and let car run for 5 min.
i checked the fans and one is working the other is not, should they both be on?
thanks for you help

Keithr726

Just replace the switches and sensors, they're not really expensive but you should have done it when you did the flush. When the temp needle reaches the 1st slash on the gauge the second fan should come on.

Ian Carr

Yes, they should both be on. Like keith said, check sensors and relays before going to the fan.

xsboost90

when car is off- check fans by hand and see if they turn free- a frozen up motor could be the problem- in which case replace the fan motor.

Bill

Pressure test the system first.

Not all leaks can be seen at idle/startup. Some only show up under pressure. Are you loosing coolant?

If it fails to hold pressure you have your problem and should see a leak at the problem area. A cooling system that can not hold pressure will boil and overheat.

If it fails to hold pressure:

If the water pump is failing it will leak out the front cover. If the radiator is failing, it will leak at the end tanks. If a hose has failed, it will leak at the cut. The oil cooler cover can leak or the water fill tank. A failed heater core will leak inside the cabin. If the head gasket has failed, remove spark plugs and water will spill out, oil will be milky, and/or your exhaust will smoke white.

If it holds pressure:

Check thermostat. Replace coolant. Bleed air from system. Check coolant temp sensor, fan relay. Faulty gauge or gauge sensor. Check belts. Check fans/relays/wiring. Fan wire connections can be hooked up incorrectly and they will spin backwards.

That should about cover it. If you dont find it there, more obscure items:

Cracked block, advanced timing, carbon on pistons, bad gas.