e30m50, overheating at idle. any ideas?

[w_elliot 7]

Hi all. i have just bought the e30m50 that was for sale on here (ex gaz) the car has difficulty keeping itself cool at idle. one side of the radiator remains alot cooler than the other side when the car is up to running temp. the car has no viscous fan fitted because going by the fan shaped marks on the radiator there was a lack of engine bay space. I am going to buy a large diameter electric fan tomorrow but i also have a feeling that i may have an airlock somewhere in the cooling system, if the car is stationary and the revs are bought up to around 1500rpm for a few seconds the temperature falls again as more coolant is circulated. the ac fan is running off a switch and I run it full time when i'm in traffic. i would like to bleed the cooling system but don't really know how to go about this with no bleed plug (still running an e30 radiator)

any tips would be awesome

cheers

[Docile 64]

i say probably the water pump and while at it change da thermostat had the same problem before

[Greg111 13]

If one side of the radiator is hot and the other side cool it more than likely has a blocked radiator or a huge air lock.

[Mark 178]

Radiator airlock

Water pump has shat itself

Have you checked the viscous fan too... the fan clutch could have died.

Thermostat buggered

Or could be a combination of all of the above...

[w_elliot 7]

cheers for the help guys, going to go and buy all of the above today, a cooling system overhaul wont do it any harm

[Greg111 13]

Half the reason is the fact it has no fan, of course it'll start to get warm at stationary.

[polley 916]

It has an electric fan. Pretty sure the fan is wired up to the temp sensor to come on automagically, and switch inside is just an over ride switch.

[Jacko 2156]

Park it up a slight up hill when you go to bleed it, makes a huge difference in getting air out. Make sure to drill a couple of little holes in the top of the thermostat if it doesnt already have them ( I stuck two 3/32 holes in mine) , makes it much easier. be sure your heater is on full hot when you do it too.

I have an M20 80 degree thermostat in mine, with a late model E30 radiator and a 14" fan on a davis craig automagic switch and it seems to work well, temp sits at roughly 1/3rd driving normally. Hot day in heavy traffic it goes up too just below half.

edit - too little sleep and too many words

Edited January 17, 2011 by Jacko

[w_elliot 7]

Park it up a slight up hill when you go to bleed it, makes a huge difference in getting air out. Make sure to drill a couple of little holes in the top of the thermostat if it doesnt already have them ( I stuck two 3/32 holes in mine) , makes it much easier. be sure your heater is on full hot when you do it too.

I have an M20 80 degree thermostat in mine, with a late model E30 radiator and a 14" fan on a davis craig automagic switch and it seems to work well, temp sits at roughly 1/3rd driving normally. Hot day in heavy traffic it goes up too just below half.

edit - too little sleep and too many words

just gave it a bleed, there was quite a bit of air in the system. I took it for a drive in some heavy traffic, temp gauge sat where it should the whole time without the fan running and the radiator is now heating up evenly. so looks like it may be problem solved. just bought a 16" electric fan which will be going in shortly and i'll do the thermostat and waterpump in the weekend when i have some spare time on my hands. m20 80deg thermostat fits right in you say?

Edited January 18, 2011 by w_elliot

[Greg111 13]

If all is good now you shouldn't have to do the rest except definitely put a fan in.

[w_elliot 7]

has anyone had experience running a davies craig EWP on their bimmer? our race car threw a rod a couple of weeks ago and won't be needing it's one for a while lol might be time to experiment

[Gaz 1061]

Sweet, glad you fixed it. Didn't think it was going to be a big job

[w_elliot 7]

Sweet, glad you fixed it. Didn't think it was going to be a big job

nice and easy. do you know if the WP and thermostat have had any attention in the last wee while? will save me a bit of time and money if theyve already been done. loving the car by the way, seems to drink less gas than my old 4age mr2 when you're nice to it which is a big bonus

[cliffdunedin 8]

i say probably the water pump and while at it change da thermostat had the same problem before

Radiator airlock

Water pump has shat itself

Have you checked the viscous fan too... the fan clutch could have died.

Thermostat buggered

Or could be a combination of all of the above...

Do BMW waterpumps internally fail? All the waterpumps (other manufacturers) i have seen fail, have leaked coolant.

just gave it a bleed, there was quite a bit of air in the system. I took it for a drive in some heavy traffic, temp gauge sat where it should the whole time without the fan running and the radiator is now heating up evenly. so looks like it may be problem solved. just bought a 16" electric fan which will be going in shortly and i'll do the thermostat and waterpump in the weekend when i have some spare time on my hands. m20 80deg thermostat fits right in you say?

Like the other guys said, you probably won't need to change either waterpump or themostat if it was an airlock, if the thermostat is not opening you will find one hose will generally be cooler than the other as the water will not be circulating.

[polley 916]

Yes, they fail internally, especially the pumps with plastic impellers.

[mark247 39]

What happened to the electric fan that was on it? When I drove that car just after I put the m50 in it would get hot with no fan, so definitely put one back in if the one I put in has gone walk about.

[w_elliot 7]

it's still there, just running off a manual switch now as the thermo one was dodgy. it just didn't quite do the job a couple of days ago when it was 33 degrees and i had an airlock in the radiator, but original fan plus 16" fan plus bled cooling system has fixed everything. still guna do the waterpump and thermostat unless you did then while you owned the car?

[mark247 39]

it's still there, just running off a manual switch now as the thermo one was dodgy. it just didn't quite do the job a couple of days ago when it was 33 degrees and i had an airlock in the radiator, but original fan plus 16" fan plus bled cooling system has fixed everything. still guna do the waterpump and thermostat unless you did then while you owned the car?

Didn't bother because it stayed fine at the correct temp.

That fan when I had it kept it perfectly cool in hot as temps last summer. That airleak must of been causing all the issues.