Still overheating!!!

[mjbst111]

Well we know the auxilary fan turns on so that would rule out fuses, resistor and the fan itself. There are two more things that could be a problem. One being the radiator temp switch that turns on the the fan through what could be the second problem, that being the relays. I believe there is a relay for each of the two fan speeds.

Honestly i would replace the switch that screws into the radiator first.. number 5 in this picture:
http://www.realoem.com/bmw/showparts.do?model=CB33&mospid=47498&btnr=17_0093&hg=17&fg=05

Hopefully that would work out for you. at least as far as making the aux fan work.

If it strats working and you still run hot, you would want to check out your mechanical fan clutch. THe fan attached to your engine.

Keep us updated so we can all learn from this. (me included!)

and good luck

 

[bmwbeemer7]

I think it may be my thermostat. This morning I let it get up to operating temp and I shut the engine off. Then I turned it back on and turned on the ac too and the temp went to 3/4 for about a few seconds and then it went back to the half mark. It will continue this everytime I turn the engine off and then back on. The aux fan does come on with the ac too like normal. I'm kind of afraid to drive it at this point of time. Any suggestions. Sounds like the thermastat but I am not sure. What do you think? Thanks

 

[mjbst111]

You can check to make sure it is the thermostat just by feeling the rubber hoses that go to the radiator. If the hose that goes to the top of the radiator doesn't get hot when it first warms up to 3/4 then your thermo could be stuck closed as you said.

 

[bmwbeemer7]

You are absolutely right. The hose does get hot to. I actually noticed that I had a small hole in the top drivers side corner in the plastic next to the metal. I sealed it up ok. So I released some air from the bleed screw. I believe it may have had air in the system from that small hole. Now it runs fine. (weird) Does that sound like that air could have been the problem? Thank you so much you are truly a lifesaver.

 

[mjbst111]

ah ok so it couldn't get up to pressure because of the hole in the system. Good call!

Glad you could get her fixed!

Yeah i forgot about bleeding the system of air. It is important in these cars...

Nice work... And thanks so much for following up. Its good to hear what the true cause was! Glad i could help. (though it doesn't seem like i did much haha)

 

[bmwbeemer7]

Also, I did notice that the auxillay fan only comes on when the ac is turned on. Even when the temp on the car went to 3/4 the fan still did not come on automatically unless the ac is turned on. Where could I find the relays for the aux fan on the car? Thank you

 

[mjbst111]

hmm i don't know on the e36's. I actually just bought mine. I knew where it was on my e30... i'll have to look into that.

Anyone else know? I assume theres a box somewhere.

these are easy to test though. If you unplug that switch i was talking about and jump the wires you'll hear the relay click and the fan turn on if it works. You can test both speeds. If they work you know to replace the switch.

 

[mjbst111]

do the jumping with the key in the 'on' position by the way.

 

[bmwbeemer7]

It was the thermostat. I changed it and it does just fine. Thanks for all the info.

 

[mjbst111]

excellent, no problem.

 

[m5runner]

Mine is still overheating. I am going to get the head gasket changed soon. I am sick of guessing what the problem is

 

[m5runner]

As unreal as this may sound, the old girl blew another water pump. This will make #4 or #5. Still gonna get the head gasket pulled soon. I hasn't overheated since the new water pump but still a little over the median. I know you guys told me not to worry about it but I just can't help it

 

[andreyiv]

Oh man, I am so sorry that happened to you. I hope you get it fixed with either the new waterpump (somehow) or with the head gasket. Mine is running just a little over the mark too and I just had a dream where it overheated and blew the expansion tank to pieces. Seems like the cooling system on the e36 is one of the downfalls.

 

[bmwbeemer7]

I have a 94 325ic and it always runs a hairline past the half way mark and it does not give me any problems. Now I did have a bad thermastat about a month ago but it was really running hot. But my car always runs at the halfway mark. Hope the info helps.

 

[m5runner]

I saw the gauge dance slightly the other day after stopping at the gas station to fuel up. I haven't changed the thermostat in quite some time now and I was thinking I should have when the water pump went bad the other day. I think I will in a week or 2 before I hit leave for Florida. The head gasket thing I really don't want to have done. I guess that's why I held off on it for so long.

 

[andreyiv]

m5runner, any luck with overheating? I've been loosing coolant lately and couldn't figure out where until one day I looked underneath the car and saw coolant dripping from the cooling/heating unit drain. I guess the only thing it could be is the heater core. Just finished with replacing that a little while ago. Maybe you have the same problem?

 

[m5runner]

Still no luck with mine. I have kinda given up and added coolant every few weeks. I can't figure out what it is at all. I don't see any leaks whatsoever. I am contemplating getting the head gasket pulled in the near future. Maybe I should just get all that stuff replaced since it will be of easy access then. Let me know how yours is running after you test it out for a week or so

 

[m5runner]

Mine has finally stopped overheating. The head gasket was changed and on my from driving it home, I lost another hose and after I replaced the hose, I thought my worries were over...WRONG. Turns out my buddy took the car again and swapped out the OEM radiator and put in an aftermarket one (I'' let all know the brand when I figure it out) and it has actually stopped overheating. He also said there was a kink in the return line going back to the expansion tank so he replaced that also. After doing all that, he can actually drive the shit more than 5 miles without overheating. Looks like I'm ok in that department but she failed emissions. Catalytic converter is the problem so I can say bye bye to another $500 bucks.

 

[Kirby]

Thanks for the update, hopefully your $$ pain will be over soon.

 

[chief]

From the 3 Series Owners Manual: Page 13
....."It is not unusal for the needle to rise as far as the edge of the red sector in response to high outside temperatures or severe operating conditions."

And here in Texas this has occurred a couple of times. Initially very disconserting, but as noted above, it is normal. Now i can sleep at night.

Oh yeah, if you are losing coolant (albiet adding coolant) try a pint of Sodium Silicate aka liquid glass. It may save you the cost of a new headgasket.