Overheating problem... again...!

[voodoo]

Hi all,

Well this must be the most common problem with bimmers. Well, my bimmer is over heating and have extensively researched and also done a lot of the mechanical work already like changing the radiator, waterpump, belts, thermos, hoses, etc. However, i am still having problems. Ive pressure tested the system, seems to me there is a leak because the system doesnt seem to hold the pressure at high and low pressures (to 15psi) and i can hear the hissing noise from released air around the thermostat area. One strange thing is that when my car overheats, i would expect maybe the coolant would be spraying out from this exact area but it doesnt! I'm now assuming the worst - that the head gasket is gone and needs changing - but checking the oil doesnt seem to show any signs of coolant/oil contamination. Well, i still need to compression test it anyways to be sure.

Does any one have suggestions or advice on further avenues i can explore to check this overheating problem? I really dont want to change the head gasket but i think it would be the likely case because i have every indication that it is blown (loss of power).

Also, my fan doesnt seem to turn on, even when the gauge is past the 1/2 way mark, but it does turn on though and not all the time! I have read that it might be that the radiator is not actually hot enough for the fan sensor and that there may be a block in the engine block that is causing stagant circulation and therefore overheating. I am suspecting that there may be a block since I had to remove some debris when i removed the old water pump (broken plastic impeller). Can anyone give me some advice on ways of cleaning out possible debris?? and also ways of testing the fan such as the relay, sensors etc.

Help would be very much appreciated... Many thanks...

voodoo

[Jeron]

Do a leak-down test to see if the gasket is blown.

Is your radiator getting hot? Feel the bottom hose.

Debris would be bad. I dont know a good simple method but pulling the thermo and pump then flashlight and fishing with a long piece of plastic, like a 18" zip tie might help.

[alk01]

I am a novice so I do not have a reply at this time, only a question.

PBs is replacing an $11.00 large lower radiator hose (located on right side) on my 1985 BMW 325e. They alledge that the alternator has to be removed and replaced ($72.00 labor) to complete the task. Is this necessary or am I being ripped off?

[Jeron]

I dunno about the alternator being removed. I dont do E30's but removing the alternator seems extreme.

However any job done by a mechanic is gonna be at least half hour labor. I recommend asking what other parts can be replaced during the same 1 hour labor, such as belts and other hoses.

[akgustin]

I fought with problems like this when I first did some engine work on my 89 E30. The problem ended up being that I did not bleed all of the air from the system. I was sure it was full of water, but apparently it had enough air to keep the pump from working properly.