Car overheating - help!

[Don (Ireland)]

Just came back from a short spin and when I got home the temp gauge was at 3/4 and going north, I switched everything off just before it hit red. I looked under the hood and no obvious coolant leaks. The top hose was very hot and hard while the bottom hose was cold (not even warm) and hard.

The waterpump was changed 15K ago (metal impellar) but the thermostat has never been changed.

The car has 70k on the clock and had never run hot before.

Any advice much appreciated!
Don
525iA '95.

[winfred]

id do the thermostat as it's probably stuck/broken

[Rory535i]

check the thermostat. Otto - German Car Parts Centre in Dublin sell good replacements. 01-497420. Mail order takes about 2 days.

[Don (Ireland)]

id do the thermostat as it's probably stuck/broken

I thought about the thermo but if it was stuck open the I would have thought the car would take a long time to heat up which is not the case, if it was stuck closed the upper hose would not be hot (which it is!)....what do you think?

[632 Regal]

stuck closed or you somehow got an air pocket in there. Try to bleed it and see if any air comes out, if not then you should do the thermostat.

[mamilapon]

Definitely a stat stuck closed but allowing just a trickle of hot coolant through.

[Don (Ireland)]

Definitely a stat stuck closed but allowing just a trickle of hot coolant through.


Thanks guys, I will change the stat and let you know....

[genphreak]

Near where the arrrow points up, it'll help u to bleed the thing... u don't want to have to mess around... and u need an 80 degree thermostat for the 535- they cost $16 odd. :) GP

[Rory535i]

[QUOTE=genphreak]Near where the arrrow points up, it'll help u to bleed the thing... u don't want to have to mess around... and u need an 80 degree thermostat for the 535- they cost $16 odd. :) GP[/QUOTE

not disagreeing or anything but is drilling the hole 100% necessary? i didn't do it to my new one and didn't have any problems???

[winfred]

drilling the hole just about eliminates the chance for problems in bleeding, it's almost vital on m20 525s imho because there such a bitch to bleed, but it's not necessary


[QUOTE=genphreak]Near where the arrrow points up, it'll help u to bleed the thing... u don't want to have to mess around... and u need an 80 degree thermostat for the 535- they cost $16 odd. :) GP[/QUOTE

not disagreeing or anything but is drilling the hole 100% necessary? i didn't do it to my new one and didn't have any problems???

[Rory535i]

ok thanks

[Rodericb]

Just came back from a short spin and when I got home the temp gauge was at 3/4 and going north, I switched everything off just before it hit red. I looked under the hood and no obvious coolant leaks. The top hose was very hot and hard while the bottom hose was cold (not even warm) and hard.

The waterpump was changed 15K ago (metal impellar) but the thermostat has never been changed.

The car has 70k on the clock and had never run hot before.

Any advice much appreciated!
Don
525iA '95.

I had the same problem and mine turned out to be my radiator. New radiator ran me $189 with free shipping. After replacing it, my overheating problem was solved.

[Don (Ireland)]

Thanks again to everyone, I will change the thermostat first, if the problem persists then the rad is next on the list.

[homer+vat]

Don read this thread, take note of post by EMW525E34 about taking the top hose off and back filling the coolant system. I had exactly the same symtoms as you and this fixed it for me. Air in the systom for sure!
http://www.bimmer.info/forum/showth...66163#post66163

Andy