Question about 1995 BMW 5 Series
1995 BMW 525I over heating issue. I repaired head gasket leak, replaced radiator, replaced water pump, replace thermostat three times, replaced thermostat housing. The vehicle is still overheating when i drive it. Does anyone know what the auxiallary coolant switch is that is on the firewall drivers side?
Hi, Sounds like you have tried about everything. Ok the aux. coolant switch is for the electric pump for the heater core will not cause an over heating condition just a longer warm up of the heater core. Has the cooling system been bleed properly if there is a trapped air pocket it will not let coolant circulate. Was the new thermostat installed correctly? They have a vent that needs to be towards the top or they trap air on the back side and cant take an accurate reading to open and close. Other areas to look at would be proper operation of the fan clutch, if they fail they can cause the fan to not lock up properly and supply enough air movement through the radiator. The aux. electric fans and their temp switches do you hear them coming on are they coming on at the right temp.
Posted on Aug 26, 2010
Or haed gasket
Posted on Aug 30, 2010
Perform a liquid block test (with the bottle of fluid over the radiator mouth.) If the blue liquid turns yellow or clear, you have hydrocarbons entering the cooling system (usually via head gskt.) If not, you have ruled out a costly repair.
Sounds like it overheats pretty easily, without t-stat! This block testing liquid is cheap, and will verify a suspected leaking head gasket without lengthy diagnosis. Hope it's better news, but good luck!
Posted on Jan 28, 2009
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