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

[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.

[Good & Tight]

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

[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

[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.

[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.

[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.

[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 ;)

[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...

[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.

[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!

[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!

[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.

[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.

[Jean]

Let me know what pump you end up getting, I've seen a few for sale under $150-200. Probably a nice tool to have to help bleed systems quickly w/o much hassle...

[Erick]

Yeah, in my little research I found a nice uView 550500 for under $100 (around $70-80 actually). The only issue that might kinda make me go meh is that it requires the use of an air compressor.

My curiosity (that has yet to be satisfied) has not yet discovered if a small enough compressor (that I can use at the track) would suffice. Because if so, it's definitely worth it to me as I can see me needing to do quick coolant bleeds at the track sometimes.

But I already set it up with my buddy to go into his shop on Friday afternoon as he already has the tool and we're going to try bleeding it to once and for all see if there are any air pockets left in the system.

By the way, I got ahold of someone who has some "experience" bleeding M30s. I had quite a laugh at reading his PM and thought I'd share. I'm sure he's reading here so he is more than welcome to join in and go on about his m30 shenanigans lol

I don't have my m30 e30 anymore but when I did have it like I say I had no temperature gauge haha and I had it blow coolant pipes off the radiator and scald my ex-girlfriend in the waffleswaffleswaffleswaffleswaffles through her trousers! Haha. So I know first hand how gay they are to bleed.

- E