Re: overheating 159 2.4
First thing to do is a pressure test on the cooling system. Google "coolant pressure test" for the procedures. Done properly a pressure test will tell you loads about the health of the cooling system without dismantling anything, including head gasket. To say that there's exhaust fumes in the coolant is BS.
Another quick test you can do to check the thermostat is to let the temp guage start to rise and then see if you can bring the temperature down by putting the heating on max temp, max fan and no A/C. If the temperature drops this would indicate sticking thermostat since the heater matrix T's off on the cylinder head side of the 'stat wheras the cooling rad is behind the t'stat, but to be 100% sure you'd need the pressure test. You can also feel the hoses going into and out of the radiator, if the engine's hot but the hoses are cold then it's likely to be the t'stat. The top hose should be too hot to touch, bottom hose much cooler.
The other point is that if it only overheats in traffic and is perfect on the motorway then the problem could be the radiator fans not coming on.
To sum up; no serious and competent mechanic would make such a diagnosis without conducting a pressure test, checking the fans work and that the rad's not blocked. Only then can you say it's the head.
Last edited by al fa cager; 09-03-09 at 23:01.