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

[Erick]

^ I might have to take you up on that offer. I'm getting very limited with the amount of stuff I can do at 10 Motorworks. I spoke to Carlos earlier today as someone said my car sounds off timing, and they didn't have a timing light to try it out. Carlos did mention the GRM e30 used to overheat in boost, and he found that tightening the head bolts solved that.

I still have not re-torqued the ARP studs since I ran the car.

I've been up since 7am on the e30. Bought a brand new OEM Coolant cap for the overflow tank (since mine broke yesterday). Did a proper bleed of the system and let it sit a bit.

Today I actually drove the car around. I'm having a "holding temperature but won't cool down syndrome".

I let the car warm up indoors at the shop. Temp gauge reading 185deg. Holds nice, no issues. I go for a drive. Temp goes up to 190deg (mind you it's a very hot and humid day... around 95deg outside). I sit at a light for a min or so, temp holds at 190deg. Cool, I can dig that.

I get back to the shop and sit outside at idle in the sun. Holding 190deg. Still fine by me. I decide to warm up the motor a bit and see if the fan will bring it back down. Rev the motor up a few times. Temperature climbs to 200deg. Idle for another 5 minutes and temp wont come down.

I take the car around the block to get airflow to cool it down. Nothing. Holds at 200deg. I bring the car back in the shop and let it sit inside (shaded) for 10mins. Check back and the car is at 210deg now and the water/coolant is boiling now.

So, pretty disappointing to say the least. Missed a nice test and tune opportunity today at a skidpad, which I would've liked to test the car out before taking it to Homestead-Miami Speedway next weekend.

Right now my only leads are the ARP Head Studs that might need re-torquing, or the timing being off and somehow affecting the cooling. If the timing is truly off, it must be by a tooth, because it drives fine. My ear is not in tune to pick up a motor off timing (the only time it happened on my M20 it was clear as daylight) so I wouldn't know for sure until I get a timing light.

- E

[ForcedFirebird]

Erick, if your water is boiling, you have a leak in your coolant system. Water will not boil if it's under pressure (think pressure-cooker). If the car won't overheat on the ride to my shop, I can run a pressure test for you.

As far as the coolant always running through the heater core at all times is not entirely correct. I haven't closely looked at the cooling system from the cars that the m30 came in, but MOST cars have a bypass valve running off vacuum - that unless the heat is turned on, the coolant mostly bypasses the core (allows a trickle to keep the coolant from going stagnant).

here in FL, the temps are brutal. A local used car dealer couldn't figure out why all his heaps were overheating, we went over there with a bag of good caps, and viola! Seeing that your cap broke, I would be suspect that the spring was bad in it anyways and allowing the water to boil, and overflow to your tank.

[bataangpinoy]

hrm.

i have no hood clearance, but the motor sits a full 1.5inch from the subframe. that has to go.

[Erick]

again, try your thermostat. maybe its not opening or closing correctly?

dont mean to hijack either, but i just put my b34.5(b34 on m1.3) in with matti's mounts, but the akg poly mounts i carried over form my m20 seem too tall. what did you guys use?

I'm rocking AKG M20 Aluminum Mounts. Not sure how that relates to Matti's mounts, but I have no clearance height-wise to the hood or the PS rack.

[bataangpinoy]

http://www.r3vlimited.com/board/showthread.php?t=177065

[bataangpinoy]

again, try your thermostat. maybe its not opening or closing correctly?

dont mean to hijack either, but i just put my b34.5(b34 on m1.3) in with matti's mounts, but the akg poly mounts i carried over form my m20 seem too tall. what did you guys use?

[chadthestampede]

the guy with the 60 billion double dollar bounty on his head !

excellent catch. surprisingly not many people get it.

[wildstoats]

Just throwing this out there but have you tried pressure testing the cooling system? That might help you diagnose the problem or at least rule out a leak somewhere. I know a couple of M30 guys have had little tiny pressure leaks in the reservoirs but instead of coolant bubbling out of them it dumps out the purge hose. Also like the guy with the 60 billion double dollar bounty on his head said, check your cap. Other than that you have tried everything I can think of. Good luck!

[Erick]

Funny you mention that, my cap actually broke today. I am having to go find another one tomorrow morning.

I was thinking to myself as I drank a few beers half an hour ago if the cap being broken could actually affect something, but my drunken logic couldnt reach a conclusion.

As for the water comment, as of today I am running a 25/75 water/coolant mix. I am willing to up the coolant, but I'd like to solve my overheating first so I don't piss coolant all over the floor.

- E

[chadthestampede]

Maybe check your cap?

making sure the system is sealed is critical. Check the level sender, cap and coolant tank neck for cracks. I had a hairline crack on the cap flange and it prevented the cap from sealing and it would allow the coolant to boil.

it might be worth pressure testing your coolant system if you have ruled out all of the normal components in the system.

[chadthestampede]

This is really interesting. I had the exact same setup on my b33 and I never had a problem with overheating. I never even went above half. I'm going to have to do more research but the only thing I can think of that is different is that you're using 100% water.

I'll try to find out some more.

[Erick]

This is really an uneventful 2 minute video, but if anyone can draw any suggestions from this video, then by all means. I know the phone was having a hard time focusing, but the number marks 190deg, and the marks go on 10deg intervals.

As soon as I shut off the motor, the overflow tank burst in boiling water.

[Erick]

Sad news, the rear piece does not seem to be helping.



So I went and got the piece this morning. Pulled the motor, installed it and put everything back together. I didn't get to run the car enough to heat cycle it more than twice, so I can't say I'm fully satisfied that the system is bled properly.

Although I'm hoping it comes down to the bleeding, it still seems too optimistic to just blame it on that as the car's cooling behavior remains pretty unchanged.

I'm thinking at looking at options for the most powerful pusher fan mankind has ever created that'll fit inside the radiator support of the e30. /rant

I spoke to zacm829 over the phone today, who also had an M30b34.5 swap, and his setup (now w/ the b34 coolant pipe in the back) is damn near identical.

Guess at this point it's still all speculation until I can do a proper bleed (if it's possible to do it even better than what it is now).

By the way, I tested the Sunpro mechanical gauge and it's pretty spot on with the temperatures. Using both a second gauge and a optical thermometer (the one that you point towards the surfaces of the T-stat housing or radiator), all temperatures were within +/- 2deg of each other. So I am pretty certain that I can say that my water/antifreeze starts boiling at about 200deg (if that's any indication of a hint)

I'll try to organize this post better later on... I feel like I just rambled way too much.

[chadthestampede]

Also this

The coolant flow to the heater core is routed differently on the B35 relative to the B34. The B34 uses a gooseneck from the back of the head, wheras the B35 utilizes a coolant hose that extends from the upper radiator hose back to the heater core on the firewall. If you wish to use the B34 method (the flow of coolant through the head may be superior), it is far easier to remove the cover plate and bolt up the gooseneck with the engine out of the car.

and

Excellent info, I can't believe I forgot about the water neck and the oil pan. I'm glad that it is all here and well documented with pics. I am one of the believers that the lack water passage on the back of the head on the b35 in the e32 and e34 is what potentially leads to the more frequent HG problems found on those two cars due to the change in the way the coolant flowed through the head.

from this

http://www.mye28.com/viewtopic.php?t=60306&start=0&postdays=0&postorder=asc&highlight=coolant+difference+b34+b35

HTH

[bataangpinoy]

i stand corrected!

Good info chad!