The OFFICIAL let's make Erick's M30 stop overheating thread

[Erick]

Yeah, it seems like its coming down to that. I just heard back from Mike Gaynor from the UK, who used to drift an M30 E30. After quite an entertaining story about how he took care of his cooling system and how he bled the system, I'm going to try that vacuum pump bleed. That will at least once and for all either eliminate the overheating or the possibility that the overheating is caused by an air pocket.

[MR 325]

+1

Fully bleeding the m30 is a PITA, and a VERY lengthy process.

Yeah, takes a while. Think it took like 20 minutes to do my buddy's we put together. I can do the M20 in 2 minutes.

[e30_kid89]

This is my hose set up:
All e34 hoses + my own design, e28 rad.


Hose in this pic goes to heater core top inlet, bottom inlet hose from top rad junction is under the inlet manifold.



'T' piece from tank to t'stat housing nipple.



I run an aftermarket puller fan that is around the same size as the stock a/c fan at the front on a switch, I drive in 30-40'C hot days in stop go traffic with fan on and never have any issues with overheating.
I have never had any bleeding issues with this setup either.

Thought I might throw this in there, seems the issue has become ridiculous and any help is good help IMO. GL with this I know how frustrating this must be

Are you doing what Otis suggested or something else? Would you be so kind to make a quick n dirty diagram?

As of now my setup has the regular non tee'd b34 upper hose and a T fitting on the hose going from the heater core to the thermostat housing which goes to the expansion tank. I grabbed a 2.0 bar cap from wreckers and switched my the 1.4. I noticed the car runs a bit cooler but still will run hot once stopped for a long amount of time like before. This thread has inspired me to review my cooling system setup. Thats amazing though in the hot ass temps down there you dont run hot at all!

[Doughnut]

^^ I now have the same setup as you do in terms of hoses.

I am going to look for an aux m20/m30 fan and wire that instead of my SPAL. Curious to see how that'll work.

Not sure if you have already done this, but leave the heater out of the equation for the time being, at least until you have the engine maintaining temperature anyway.

Hope my pic helps other people with heat issues too!

[KenC]

You have enough fan to cool, your not getting good coolant circulation, keep bleeding it.

+1

Fully bleeding the m30 is a PITA, and a VERY lengthy process.

[Brian D]

If you guys read the whole thread, all this has been done already ;)

Well hell, then it's possessed. Drive a stake through it's heart.

What I'm saying is you've missed something. If the radiator is cool and the engine is overheating, you either have a flow problem or the engine is sick. I had an M20 head that held 21" of vacuum cold, and was cracked like a bitch.

Or maybe just a bigger fan...

[ForcedFirebird]

Have you changed the water pump yet? If it's not that, I'm betting you have a slightly cracked head/block that is pressurizing the cooling system when the engine warms up. Fuck man, you've changed everything else, stop beating your head against a wall.

Just go buy a some of that block tester shit that detects combustion gases in your cooling system. Then you will know for sure if the cooling system is being pressurized by combustion gases i.e. a cracked head or block.

If you guys read the whole thread, all this has been done already ;)

[Adrian_Visser]

Just go buy a some of that block tester shit that detects combustion gases in your cooling system. Then you will know for sure if the cooling system is being pressurized by combustion gases i.e. a cracked head or block.

[Brian D]

...as the radiator is often really cool according to the laser thermometer, and even the return hose is chillin at around ~170deg while the thermostat housing is already at 195+.

I also spoke to two other M30 gurus and by just describing the issues/symptoms they almost instantly pointed to a bad cylinder head or maybe even a cracked block.

^^ I now have the same setup as you do in terms of hoses.

I am going to look for an aux m20/m30 fan and wire that instead of my SPAL. Curious to see how that'll work.

You have enough fan to cool, your not getting good coolant circulation, keep bleeding it.

Have you changed the water pump yet? If it's not that, I'm betting you have a slightly cracked head/block that is pressurizing the cooling system when the engine warms up. Fuck man, you've changed everything else, stop beating your head against a wall.

[Erick]

^^ I now have the same setup as you do in terms of hoses.

I am going to look for an aux m20/m30 fan and wire that instead of my SPAL. Curious to see how that'll work.

[Doughnut]

This is my hose set up:
All e34 hoses + my own design, e28 rad.


Hose in this pic goes to heater core top inlet, bottom inlet hose from top rad junction is under the inlet manifold.



'T' piece from tank to t'stat housing nipple.



I run an aftermarket puller fan that is around the same size as the stock a/c fan at the front on a switch, I drive in 30-40'C hot days in stop go traffic with fan on and never have any issues with overheating.
I have never had any bleeding issues with this setup either.

Thought I might throw this in there, seems the issue has become ridiculous and any help is good help IMO. GL with this I know how frustrating this must be

[Good & Tight]

You have enough fan to cool, your not getting good coolant circulation, keep bleeding it.

[KenC]

PM CorvallisBMW about. I know he struggled with his b35 cooling system for a while. I think it took him like 10 heat cycles to finally get all of the air out of the system... even with the front elevated every time. They're a BITCH to bleed.

[Erick]

Did the carbon tester today at my buddy's shop. The car passed the carbon test, so maybe there is hope for this cylinder head.

Considering I did a quick bleed after putting the e34 hose, I'm thinking it might be a mix of two things that might be causing it... I'm thinking there might be an air pocket with a slightly incapable fan syndrome.

Even after bleeding this system a million times in a million different ways, I'm curious to try one of those vacuum pumps that'll suck out any air out of the system.

We let the car idle for a few minutes at the shop and observed it's behavior. As usual, the temperature keeps creeping up. The fan somewhat does it's job, as we checked the hose temps with the laser thermometer (there was about a 10-15deg difference between the radiator hoses), but as the water going in rises, so does the water coming out.

Also, on the way back home, I tried to drive the car without the fan on. The fan as it is makes a BIG difference. It holds the car from overheating big time. While in stop and go traffic (traffic lights), the temperature creeps fast... I was almost up to 210 in between 3 lights. When I got up to speed, the temperature (at about 40mph) started holding at 210... slowly creeping down, and when I turned the fan on, it started going down much quicker.

Just driving around without the fan simply wouldn't do on this M30.

Based on those things, I'm starting to lean towards some crazy stupid air pocket that needs to be brought out somehow. I want to see if I can use a vacuum pump to suck that out, and see how the car behaves then. I'm also thinking of sourcing a factory M30 aux fan to replace the current SPAL.

Thoughts, suggestions? By the way, I appreciate those already on the lookout for a cylinder head. I'm going to run a few more tests, but worst case, I'll go ahead and look into swapping heads.

- E

[Good & Tight]

My carbon tester is my nose, if he's running straight water it will smell like exhaust and sometimes will have a slight oily film.

I pressure tested the coolant system, no external leaks whatsoever.

I don't have a carbon tester, but suggested Erick test the coolant for carbon contamination before pulling anything apart.