Alright M30 guys, I'm sick of this overheating issue....

[Garageaholic]

I'm driving along at 60mph, and the temp gauge runs fine at 1/4 hot. Once I stop, like waiting at a red light for 2 minutes, it goes past halfway and ALMOST into the 3/4 zone. Even with my E-fan on high, it won't cool it down. BTW, I have plenty of heat coming through my vents, so the air isn't there. My coolant hoses are pretty pressurized and If i turn the car off and open the overflow tank, coolant will come spewing out.

This is in 45 degree weather too. I'm scared what's going to happen in 80 degree summer heat..


HOW THE HELL DID YOU GUYS GET THE AIR OUT? WHAT'S THE HEIGHT PROCEDURE BETWEEN RADIATOR,COOLANT TANK, ENGINE?


What tricks are there that I may have missed?

[Garageaholic]

Bump.

I measured that my radiator is mounted 1" below the top of my thermostat.

I think I may have air by the thermostat, causing it not to open as often as it should. But with that being said, Why can't I bleed it with the bleed screw then?

And my radiator is hot though...

[euroshark]

Try jacking the front of the car up and pumping water into the overflow tank at a slow pace with the bleed screw open. I think you have an air bubble as well... Or your cooling fan is too small.

[Garageaholic]

Ok,,, i'll try that tomorrow.


Is that how you did it?

[euroshark]

Yep, I think it should work!

[MrK]

I was having the same exact problem, and bleeding forever with the front of the car jacked up helped, but if I stand in traffic for too long, it still eventually overheats. I think our A/C fan is not enough to cool the m30. I'll be upgrading to a proper engine-cooling push-style electric fan, and I'll keep you posted.

[bmw335isturbo]

I'm driving along at 60mph, and the temp gauge runs fine at 1/4 hot. Once I stop, like waiting at a red light for 2 minutes, it goes past halfway and ALMOST into the 3/4 zone. Even with my E-fan on high, it won't cool it down. BTW, I have plenty of heat coming through my vents, so the air isn't there. My coolant hoses are pretty pressurized and If i turn the car off and open the overflow tank, coolant will come spewing out.

This is in 45 degree weather too. I'm scared what's going to happen in 80 degree summer heat..


HOW THE HELL DID YOU GUYS GET THE AIR OUT? WHAT'S THE HEIGHT PROCEDURE BETWEEN RADIATOR,COOLANT TANK, ENGINE?


What tricks are there that I may have missed?

The trick that I have learned is the placement of the water over flow bottle!!
I have tried alot of them even a larger costom radaitor I find the factory tank on the driver side finder works the best its almost straite accross from the Thermastat and just a little higher.

This all depends on how high you have your engine, also the engine should be placed to where you should just barly be able to put your fingers between the rack and the oil pan.

[SchnellerVert]

The parking on a hill system is also used on the dreaded E36 cars which are known to do the same thing with air pockets.

[Rocla]

Trick I use with cars that have bleeding problems is a large beverage bottle wit bottom cut out, place the bottle to expansion tank filler and fill the bottle with coolant. Pump the hoses, when the level of coolant is higher than it could be with just the expansion tank, the air escapes more easily. After pumping hoses untiil no air comes out run the engine with bottle in place for few minutes and let it cool again, repeat few times.

Putting car to uphill helps too with this trick.

Then comes the messy part, you have to get the exess coolant out...

[george graves]

I've never had a single prolbem. What radiator are you using? I have a e28 rad. and a "spal"??? fan ...I only need to run it sitting parked for more then a min. (drive thru's are the worst sucking up someone's hot ford 340 exhaust...) I do know m30 kinda HATE heat, 3/4 on the mark and I hear valves clicking and nasty-ness all around.

Ive only been to the 3/4 mark only once (stop and go traffic on a hot day, and my fan wiring went out) - major lost of power. It seems that m30 love to heat soak. Once that big intake mani heats up, you can't get any HP till you shut it off and have some lunch.

[Garageaholic]

My thermostat is a little higher than the top of my radiator. is that ok?

[bmw335isturbo]

Mine is too.
as long as you have your overflow bottle higher than everthing when you bleed your system and have it high enough to keep water above the thermastat.
I have found that the 88 325is had it top of driver side fender I wedged it up bearly touching the under side of the hood and it workes just fine.

[Garageaholic]

Okay, an update:

I had the car on an uphill incline and drained alll the coolant out of the radiator (the blue radiator screw on the bottom).

I filled it up slowly as I left the bleeder screw open. I filled up the coolant until the bleeder screw overflowed. All the time, I physically lifted the coolant reservior about a foot above the whole system. Once I closed the bleeder valce, i kept filling it up until I had a good level in the reservior. I closed it up and put it back in it's place.

I started the car and idled it until it got to temperature, I bled it once from the screw, but only coolant came out, so that was a good sign.

I drove it around town and the temperature was a little cooler, but only until I stopped the car and let it idle for about a minute or two did it start getting in the 3/4 zone again, even with the fan.


I think that maybe the fan is sucking up more juice from the alternator and not cooling enough, bc when I turn the fan off, the engine actually runs a tiny bit cooler. lol believe it or not.

I think I may need to get a bigger/better cooling fan.


I need suggestions. Thanks alot for the help guys. It works better, but not perfect.... yet.

[E30/M30]

Is the fan big enough ?

How close to the rad is it mounted ?

How/when does the fan turn on ?

Is your bottom rad hose getting hot when it's up to temp' ?

I physically lifted the coolant reservior about a foot above the whole system

Thats the way i do it, i never have any trapped air problems doing it this way.

[MrK]

In a similar note, who knows what cars' engine fans were electric pushers? Perhaps I can use one of those instead of the a/c fan, which was not necessarily designed to cool the whole radiator on its own.