FITTING A THERMOSTAT

Hi Trin,

The replacement 'stat should not need gasket sealant if both surfaces are plastic. It won't harm things to put the tiniest smear of sealant on, but there should be no need.

However, the sentences: "BMW 316i 1995 - M" and "Head-gasket failure" are good friends with each other.

A leak can occur around the 'stat housing when head gasket failure is imminent or already beginning. This leak can itself be caused by a fracture in the manifold, at the point where it meets the thermostat. The 'stat failure can also be one of the causes (overheating) that results eventually in head gasket failure.

I am not saying that your partner's car DOES have a failing head gasket but it may be wise to run the Beemer with its 'old' thermostat in position while you check that all else is well. Putting a new thermostat onto a cracked housing or onto a 316 that already has gasket problems may prove to be a waste of time and money, since it overlooks the main problem. With the engine still running, check for rock-hard radiator hoses (and coolant leaks around the radiator as well) after even a short run. Take a VERY close look at the aluminium side mouldings and top and bottom mouldings of the radiator (you can see them if you try). If they are bowed outwards or if the plastic end caps each side are weeping coolant, you may have other challenges to solve.

You will have to replace thermostat sealing ring and also use silicone gasket sealant after cleaning up cyl head and thermostat housing . Here is a walkthrough with pictures which should help you .


http://www.pelicanparts.com/bmw/techarticles/E36-thermostat/E36-thermostat.htm