dont even know where to begin, just very pissed!

[pejsa]

so ive had this car for about a month, its a 91 325i. and its just been a nightmere. im not mechanically inept either so i thought id be able to figure this car out.

first thing i did when i got it was replace the timing belt, water pump, front mail seal, thermostat and overflow tank cap.

1. when i got it it was overheating

cause.... no thermostat. so i put a thermostat in it.

2. car over heating again 3 days later.

cause.... bad clutch fan. so i bandaid fixed it with a solid fan clutch.

3. car over heating 4 days later.

cause.... punctured coolant line for the heater core, so i bypassed the core all together dont need it in socal.

4. car over heating a few days later.

cause.... unsure? just bled the cooling system and topped it off.

5. car drives for about a week and starts the same crap all over again.

ive boiled the thermostat and it popped at 180* the way it should, cooling system has good pressure, coolant isnt gushing out of the overflow line.

ive also block tested the motor numerous times and done compression test on it all seem fine.

sorry about the soapbox rant guys maybe you all could shed some light on all this nonsense :?

[Jafxod]

Have you considered swapping?

My m50 is on all water, never tried to "bleed" it. And my temp gauge doesnt even work, and I have no issues, nor do i worry about it. But best of luck, i dont miss my m20 at all.

[pejsa]

i got this to be a daily while i swap my other project lol i dont want to swap this.... honestly thinking of selling this, but i love e30's this is my 3rd one....

and if i do sell it id probably buy another one and be in the same situation all over again =/

[MR 325]

Have you considered swapping?

My m50 is on all water, never tried to "bleed" it. And my temp gauge doesnt even work, and I have no issues, nor do i worry about it. But best of luck, i dont miss my m20 at all.

What a ridiculous reply. Swapping is not the answer, M20 engines are very simple.

Running on water doesn't make you cool, enjoy the buildup and rust in your cooling system. Not bleeding your cooling system is absolutely stupid, all BMWs need it. A non functioning temp gauge, yet you say you have no issues. HOW DO YOU KNOW.

[E30Gus]

Clogged radiator?

[Brandon12V]

you might try hooking up an aftermarket temp sensor so you can see specifically when it is overheating. Also, your AC fan may not be kicking on when the motor reaches a certain temp. A clutch fan can only cool the radiator so much at idle. make sure the high/low speeds are both functioning on your AC fan.

[scrowner]

Your step 1 listed - no thermostat - should not be a cause of overheating. I would suspect either blocked radiator or water pump failure.

[_r2h]

Your step 1 listed - no thermostat - should not be a cause of overheating. I would suspect either blocked radiator or water pump failure.

I like where this guy is headed. Also agree with the comments about the aux fan not coming on.

[blocke]

Prob a very dumb question, but did you put all the belt on correctly when you put it all back together after doing the timing belt? If you somehow had a brain fart and didn't route them all over the crank pulley, then the water pump could not be spinning, resulting in overheating. Just going out on a limb.

[E30Gus]

AC fan not working would not cause this. Many people on here remove that crap when their AC stops working. My car can idle for a long time and not over heat with the AC fan removed. If the car is over heating and the fix is the AC fan, then there is another problem in the cooling system somewhere that may not be @ 100% failure yet...like a partially clogged radiator.

[Brandon12V]

Actually, yea it can. Climate, the degree thermostat, and overall capability of the cooling system dictate it's effectiveness, but it can certainly cause overheating after time at idle. Why? because I've experienced it more than once. After removing my entire AC system with a full head rebuild, timing belt, water pump and tensioner. I threw a spal fan in there and tossed the clutch fan. if it wasn't necessary, then BMW wouldn't have put a high/low speed resistor in there. They would have it just kick on when using AC. I understand what you're saying, but it does have a purpose. I agree that it is probably not the only cause(depending on how fast said car overheats), but OP needs to rule out the possibility of it working improperly.

>>>> when your engine starts to overheat again, the AC fan should kick on to high speed @ 205 degrees, iirc.
>>if it is not, a fuse(s) may be blown.
>>if it doesn't kick on at all when you press the AC button then it IS a fuse.
>>if it doesn't run on low speed, but kicks on high speed when the AC button is depressed it is your resistor.

[yert315]

You need to be more specific with when this overheating occurs and how hot it gets.

Are we talking just past half at idle or buried in the red at 60mph? both? neither?

[Acehye559]

My cousins sedan had same issue, auxilary fan wouldn't turn on cause the sensor on the radiator was bad. He Had everything changed like you as well, then one day my car was parked and the auxiliary fan kicked in and we decided to check if his would turn on. Ended up being that his aux fan wouldn't kick in, changed sensor because the fan was good. Problem solved. Try it and see.

[Acehye559]

I forgot to mention two things. Here in fresno,ca temp reaches 100+, so every little thing counts. We added a fan shroud cuz his was missing and we also changed his radiator as well. His radiator was pretty beat up. When does it overheat? While driving or while idling?

[Hey_You]

Perform Block Test since you have overheated your engine so many times. Check your oil on your dipstick, see if it's milky. You may have a headgasket issue.