944S2 airlock in cooling system

[Guest]

Hello,
I wonder if anyone can help me. I've just carried out what should have been a simple task on my 944S2 but nothing is ever simple is it !

I have just replaced the 'O' ring and plastic union at the water pump end of the hose which connects from the filler tank to the pump. I then filled the tank up to the 'max' mark. I thought I would run the engine until the thermostat opened and then top up the level as necessary.

It was a bit slow warming up so I decided to take it for a run, however I had only travelled about half a mile when I had to stop at a junction and to my alarm smoke started rising from the edges of the bonnet despite the needle on the temperature gage reading normal (half way up, which it doesn't normally rise above anyway). I immediately stopped the engine and rolled back to park.

After it cooled down I returned home. On checking, the water level was still at 'Max'.

Obviously there was an airlock somewhere. I consulted my Haines manual which said to open the bleed nut on the top hose, start the engine and when it had reached normal operating temperature (the fan has turned on and off) and the coolant issuing from the bleed nut has no more bubbles, tighten the bleed nut and top up the tank.

That is what should happen, this is what actally happened. I undid the bleed nut and let the engine run, it reached normal and carried on rising. The fans did NOT come on, the temperature gauge continued to rise ( my temperature was also rising by now) and steam not water was venting from the bleed plug. The needle was now almost on red and that was all I could take. I switched it off.

I noticed the heater didn't send out warm air. I know the fans do work because occassionally they are on after I switch off the engine. The car never normally overheats even after a long run.

Can anyone please tell me how to bleed the system.

Mike
Rotherham Sth. Yorks
PCGB member

 

[944cabby]

Mick. i was advised to bleed mine with the car facing uphill to assist the movement of air through the system.It took me about 3 attempts when i did mine before xmas but seems ok now - same prodedure as you've done but i didn't go for a run straight away i did it in stages letting it cool down in between after the thermostat opened and all the hoses were hot.
Each time i bled it though there was air released.

 

[Guest]

Hi 944cabby,Thanks for replying to my question.I will do what you suggest. Many thanks.Best regardsMike

 

[Guest]

Hi Andrew,Thanks for replying to my question.It was white plastic and I never thought to check if the passage was clear. I will do what you suggest. Many thanks.I checked out your website and will keep it in my folder for future reference.Best regardsMike