A recurring problem with the BMW E36 Series vehicles is that leaks can develop around the housing for the thermostat. This will cause you to lose coolant and can lead to overheating problems with your vehicle. What typically happens is that the plastic thermostat cover will warp over time and create little openings along the seams that are difficult to seal. To adequately fix the problem, you should replace the plastic cover with an aluminum one. Here is how the average BMW owner with limited mechanical experience can change the thermostat cover themselves in an afternoon.
The thermostat is located directly behind the radiator fan on a BMW E36 Series vehicle. There are two hoses connected to the housing. One is the hose coming from the radiator and the other is a hose which goes from the thermostat cover and into the engine block.
Removing the Thermostat Cover
You have to remove the two hoses connected to the thermostat cover. However, before you do this, you should make sure the car engine is cool before taking off the hoses to prevent getting burned and injured. You should also place a large catch basin like the top of a garbage can under the front of the car to catch any radiator coolant that will leak out as you remove the hoses.
The hoses are connected to the housing cover with hose clamps. Loosen the clamps with a screwdriver and slide the hoses off of the fittings on the cover. There are several bolts that hold the cover to the thermostat housing. Remove the bolts and take off the cover.
You want to clean any remnants from the gasket on the cover from the surface of the housing unit.
This is an opportunity to upgrade the plastic cover to a better one made out of aluminum. Aluminum can handle the temperature changes better than plastic and will last a long time. This will be an aftermarket part that you can get through your local auto parts store or online.
Install New Cover
Make sure the gasket on the new cover is in good shape. Set the cover over the thermostat and bolt it in place. You should then reconnect the hoses. You also want to replace any radiator coolant that leaked out when you removed the hoses. If the coolant in the catch basin is clean and free of debris, you can pour it back into the radiator. Otherwise, you'll have to use fresh coolant from a container.
To learn more, contact a company like Jim Stephen's Foreign Car Repair.