525i overheating

My 94 525i started overheating. I did the air purge procedure first hoping it might be an easy fix. Absolutely no air or coolant came out of the bleed valve. I am assuming the radiator is plugged and/or the water pump needs/should be replaced along with the thermostat as long as I'm at it. What else should I look at?

Your probably right on the money with the water pump , it must have the old style with the plastic impeller . If it is that I would also do the thermostat and housing too .

Sent from my Desire HD using Bimmer App

I have learned to throughly test the Fan clutch will rolled news paper with car hot. See if the paper rolled up will stop the fan easily . If Yes its the cause .I have seen two fail and cause over heating scenarios .I installed heavy duty ones on both my cars proved to be lifesaving for the cars engines. If the fan clutch is strong I would start a radiator replacement or removal and cleaning .If still over heating I would do the rest of the cooling system.

Thanks guys. As soon as I can get it towed home I will do it all.

Back flush radiator + the processes other people have recomended. If you replace the t'stat drill a small hole in its flange (1/16") to assist with bleeding, check that bleed hole is clear, set heater to full heat and park veh with nose as high as possible.

go to the extreme foregin racing auto parts sites they sell universal cooling fans/parts/pipes/hoses too keep everything super cool. Although you wont need it for racing. Not a bad idea.

Originally Posted by NAVYMAN

My 94 525i started overheating. I did the air purge procedure first hoping it might be an easy fix. Absolutely no air or coolant came out of the bleed valve. I am assuming the radiator is plugged and/or the water pump needs/should be replaced along with the thermostat as long as I'm at it. What else should I look at?

You should have coolant coming out of your bleeder valve especially if your engine is overheated. It sounds like you are leaking or burning coolant somewhere.

Touch your upper radiator hose. If it is hot, then both your thermostat and water pump are working fine.

Cool the engine down, refill with water and cheap brightly coloured coolant, bleed, and then watch it at idle for ten minutes like a hawk and see if there are any leaks or steam escaping from anywhere that you can spot. Make sure someone is sitting in your car and monitoring the temp gauge. If it gets to the 3/4 mark, shut down the car.

With the engine running and the radiator refilled, hold a cold surface or your wallet to the mouth of your tailpipe. If there's alot of condensation forming and it isn't wet and rainy where you live at that time, this means that coolant is getting into your combustion chambers and being lost out the tailpipe, depleting coolant and overheating the car eventually. In this scenario, you've either got a cracked head or a busted HG (headgasket, more likely here). Write back if you notice this and we will guide you through your next steps.

Check your dipstick to see if the oil has turned milky. If so, then coolant is getting into your crankcase. Very bad news, probably a cracked head or (less likely) a HG problem.

Do not panic as you do all of this. That's the biggest enemy. Most overheating issues do not lead to permanent damage to the cylinder head and HG (this is the worse scenario). And even if you've solved the problem, carry 5-10 gallons of water in your trunk for the next 2 weeks and only discard if this situation does not recur.

Originally Posted by BMWFatherFigure

Back flush radiator + the processes other people have recomended. If you replace the t'stat drill a small hole in its flange (1/16") to assist with bleeding, check that bleed hole is clear, set heater to full heat and park veh with nose as high as possible.

I really wouldn't advise this. Too many ways for this to go wrong if you're not careful and its a waste of time for nearly zero additional short/long term benefits.

This radiator is EASY to bleed. In fact, it is fun to bleed (the radiator) ! Air pockets in the cooling system can only get there and stay there if done by people who literally don't bleed their radiators at all after a flush or removing hoses etc.

Originally Posted by luckydog

I have learned to throughly test the Fan clutch will rolled news paper with car hot. See if the paper rolled up will stop the fan easily . If Yes its the cause .I have seen two fail and cause over heating scenarios .I installed heavy duty ones on both my cars proved to be lifesaving for the cars engines. If the fan clutch is strong I would start a radiator replacement or removal and cleaning .If still over heating I would do the rest of the cooling system.

this is highly unlikely to be the problem, unless the aux fan is also busted. i agree it wont be helping if its not right, but it wont cause overheating if this is the only faulty part on the car