overheating***95' 325i

[chiboons]

Ok i was driving on the highway about 2 month ago just after buying this car and i noticed the temp guage was at red for a second so i quickly pulled over opened the hood and found a slit in my upper radiator hose where all the steam was busin out from.. i did a cave man fix with super glue and plastic bag and drove the remaining 74miles home safely after which i replaced the hose with a new one. Now about 3weeks ago i was running errands with the ac on and after quite a while in traffic noticed my temp guage rising again so i turned the ac off and it helped a bit but didnt cool off right away. I've now checked with the mechanic and he says we'll start with fan clutch and fan shroud replacement, i noticed the fan blade doesn't rotate quite straight. Don't know if it could be another problem, just verifying before i go spend $400 bucks with school around the corner...and also is it possible the quick second overheating would have caused any problems i.e gasket or anything even though i haven't noticed any changes.. i will greatly appreciate your feedback, thanx

[themadhatter]

fan shroud is a static part, doesn't need to change. the clutch however along with the thermostat is a good idea to replace. if you were over heating at highway speeds, it wasn't your fan clutch.

[mdh]

Overheating engines with aluminum heads is a big danger. The heads are susceptible to warping which then leads to compression loss, blown head gasket, coolant leaks, etc. You would also be in serious danger of burning your exhuast valves especially with a higher mileage engine. The excess heat is retained by the carbon deposits on the top to the exhuast valves and ports.

I would start with inspecting/replacing the easy things first:
1. Bleed system at least three times to purge any air.
2. check all coolant hoses for leaks. Is there a puddle under your car each morning? Do you smell the sweet aroma of antifreeze when you walk past the front of your car?
3. thermostat. Overheating can cause these to stick closed.
4. Is there oil droplets floating in your coolant resevoir? Is there water on your oil dipstick (muddy brown color and or foamy). Have you noticed your coolant level keeps dropping but you haven't seen any leaks under the car?
5. Water pump. Not sure when the factory stopped using the plastic impeller versions, but this is a known failure point. Unfortunately, about the only way to check this is to remove and verify impeller material.

All of the above items should be explored before dropping $400 for items that are very unlikely to need replacing. If your last overheating episode occurred during stop-and-go traffic, it may be the fan clutch. If it happened at constant highway speed, the fan clutch is not even engaged and would have no influence upon cooling.

6. Find a new mechanic.

[92redE36]

check your water pump...if the impeller blade is bent like mine was, that could cause the reason why your fan spins in an akward way.

[chiboons]

ok i just check the cluth/fan and noticed there're couple cracks on he fan(not the blade but the circular part that holds them all) so might this just be the problem why it wobbles and doesnt spin faster even when you hit the gas....was thinking about just changing the fan alone and see if that corrects the problem or should i go ahead and change the fan blade and clutch...thanx

[themadhatter]

the clutch is beat if the fan isn't spinning faster when you hit the gas, that's it's whole job.