AO Platinum Member
Join Date: Feb 2002
Location: The land that Time forgot
Yes, I think you need to verify whether the "overheating" is real or not first... but in my experience those little sensors very rarely fail, so assume that there is a problem.
An air-lock is the least likely problem in itself since the system is self-purging. If hot air does not come out of the heater, then that might suggest a different air-lock problem - usually caused by the head gasket.
> To test for air in the system (when cold) loosen but don't entirely remove the air bleed screw on the back of the radiatore (by the r/h headlamp). Let any air out until coolant starts coming out.. That's the rad' bled. Don't take the screw right out.. or you'll never get it back in as coolant is ****ing out all over the place.. just loosen it a few turns until it hisses or ****es.
>> If there is pressurised air in the rad' that will stop coolant getting in there so this should solve the immediate symptom. Test the car again (cold) after a day or two and see if there is more air in the system. If you keep getting air in the system, that's a goosed head gasket. Nothing else.
A thermostat failure or a water pump failure would all cause your symptoms too. Thermostat is an easy test since the rad' will be cool while the hoses on the engine will be boiling hot. Change the 'stat and Roberto should be your mamma's brother.
Water pump is more tricky to diagnose since only a physical inspection will prove it for sure... which is a pump (and cam-belt) off job. How old is the water pump? They can run to 100,000 miles or more.. but if you definitely changed yours at the last cam-belt change for example, that would make it less likely to be the culprit.
The sensor could be at fault.. You could try getting a second-hand one and fitting it.. It'll just cost you a few quid and some coolant so if the other tests check out okay, then do this fairly soon (certainly before dismantling the water pump).
No bullets for Chaingun..