[cauzomb]

Another thing, if your car has air conditioning, if the A/C switch is in the on position, the radiator fan on the passenger side will be on FULL with the key in the on position, late models might have both fans on full, not sure.. If the cooling fans come on when the car gets up to temp, the thermoswitch and cooling fan relay are working.. If you turn off the car and take the key out while the cooling fans were running, and a cooling fan stays running, the thermoswitch and the cooling fan relay, and the slow speed resistor are working..

It sounds like you are loosing coolant. Check all your hose clamps, check for water stains around the radiator cooling fan thermo-switch, it's below the top radiator hose on early 944's, not sure where it is on a late model.

The thermofanswitch may not leak untill there's pressure in the cooling system at temperature, may dry right up after shutting down the car due to the heat in the radiator.

My early 944 had a small weap from the thermo switch gasket, just took some re-tightening to seal it back up.. I probly didn't tighten it enough when I put in the new switch, trying to be carefull not to crack the radiator end tank.

When the car is "cold" remove the coolant res/expansion tank cap, then start the car and let it warm up while watching for bubbles and puff's of smoke in the tank.. Don't run it long, if you aren't hearing bubbles or seeing smoke puffs in the expansion tank after the cylinder head is hot to the touch turn off the ignition, then put the expansion tank cap back on.

If it begins to overflow before you get a chance to feel the temperature of the cylinder head,, shut off the engine. Might want to have a drip pan under the tank/fender area to catch any coolant that might come out.. It's pretty nasty stuff, probly toxic n you don't want it leaking out.. Coolant shouldn't come out but if it's a bad head gasket leak, the combustion pressure might push the coolant out of the open expansion tank, before the coolant is even warm to the touch.. If it gets up to temp, you might get boiling of the coolant, due to no pressure in the cooling system.. The pressure cap is designed to hold a certain amount of pressure to prevent the coolant from boiling in the head.

If you have bubbles in the tank, it's a sign of a bad head gasket..

Another sign is excessive steam from the exhuast but with the amount of water and alcohol they put in the fuel these days, it's hard to tell if the steam is just the warm air/water vapor condensing/fogging. Most cars have steam at warmup, but a bad headgasket usually blows steam all the time, worse as cooling system pressure increases, the added pressure in the cooling system will push more coolant past the gasket, into the combustion chamber.


Alternatively, and less dangerous, perform a leak down test on each cylinder at top dead center/compression stroke, with the expansion tank cap off. If you get sounds of bubling at the expansion tank while doing the leakdown test, you probly have a bad head gasket..

The leaks are usually between the water passage and just one or two cylinders, so you will have to do a leakdown on each cylinder to determine if/where the headgasket is leaking..