944S2 overheating problem

[tonypanic]

Hello all

My 944S2 let me down the other day and had to be recovered home due to the engine temp getting very warm just over 3/4's before finding safe place to park(not went into red at all). Had a look and found the fan relay not working, so replaced that tonight (not cheap). Then found engine still getting hot around 3/4's up temp gauge and water being blown out of header tank, all thouigh fans are working now. Has any one else had these probs, would I be looking at head gasket failure or someting more simple like thermostat or water pump. Can understand that it is not easy to diag via an email but any help would be good.

Cheers Tony.

[softinthehead]

would hope and suspect its the thermostat. cheap part to replace - mine was less than a tenner if i recall. quick and easy to fit. and keep fingers crossed.

if water is blowing out the header that would seem to imply considerable heat/pressure. You might wonder about the accuracy of your temp gauge?

[zcacogp]

Water pumps do fail occasionally, but I hope for your sake that it isn't one of those (big job, best done at the same time as a cam belt/pulley change.)

Have you changed anything recently / drained the coolant or similar? Check for blockages in the radiator (although these aren't common) or airlocks in the system (much more common and tricky to get rid of. But very cheap to fix.)


Oli.

[PJS917]

Sounds like an air lock in the system, run the car up to temp and bleed the system from the valve in the top hose, if air escapes that is most likely your problem.

[zcacogp]

PJS917 said:

Sounds like an air lock in the system, run the car up to temp and bleed the system from the valve in the top hose, if air escapes that is most likely your problem.

Aren't they meant to be easier to bleed if you can raise the front of the car?*

Park on a steep hill, or jack the front a little before starting.


Oli.

* - I may be completely wrong here, as usual.

[hartech]

The S2 can overheat for a variety of reasons amongst which are:-

Impellor on back of water pump has come lose.

Water pump bearing seizes when hot.

Cam belt lose.

Thermostat has broken.

Fan switch, fan or relay not working.

Head gasket gone.

Oil channel in head cracked (oil in coolant).

Baz

[tonypanic]

thanks for all replies.

Took the thermostat out tonight and checked found to be ok. Looked into the air lock issue then and found lots of air in system, heater not getting warm now. What is the best way for removing air, worried about keep running in case of damage to head/gasket. Is there any way of checking water pump without removal.

Cheers Tony.

[hartech]

Tony - when the thermostat is open (at running temp) squeeze a rubber coolant hose pipe together and then rev up the engine - if the impellor is OK you will feel a rise in pressure in the pipe.

Also the top hose and radiator should be hot and the bottom hose from the radiator a little cooler to the touch - test these as well.

The bleed screw is on the side of the top front hose casting facing the inlet camshaft at the front of the engine. It does not need completely removing as it has a hole drilled in the side. Just get hot then slowly undo it and bubles of air will come out - until just coolant comes out. If the level in the header tank goes down too much - slowly remove the cap and top it up while the bleed screw is lose.

Baz Hartech

[tonypanic]

cheers Baz top hose was hot last night and bottom was cooler, will try the squeeze tonight and the bleed screw. Many thanks Tony.

[silverS2]

Might be worth trying a new radiator cap as well, just thinking out loud......, simplest thing and all that.
Andy