Guys, I have a 96 BMW M5 that slowly looses coolant causing the vehicle to overheat. No leaks are noticeable. I have heard of this similar problem from many other owners but can't seem to find a solution. Has anyone here come across the same problem and found a fix? thanks for help.....

Ray

change the thermostat and new radiator cap.

Quote:

change the thermostat and new radiator cap.

if it dosent solve your problem, check your plugs which will indicate you that there might be a head gasket leak.
Good Luck.

If you're losing a considerable amount of coolant with no sign of a leak, it's either going into the crankcase (you would notice the oil being milky and thick), or it's burning in the combustion chamber and going out the tailpipe. Most common cause being a head gasket.

It can be tested by pulling the plugs and applying air pressure to each cylinder one at a time, rotate the crankshaft to top dead center, and look for the air gurgling up in the radiator.