M30 Cooling System Pressure and Air

cvillebimmer · Post by **cvillebimmer** » Aug 03, 2008 6:24 PM

I have two issues with my cooling system, which i believe are related, but I can't seem to pinpoint the problem:

1) The system never de-pressurizes. Even after sitting overnight, both the upper and lower coolant hoses are hard as can be.

2) Air is getting into the cooling system with no visible displacement of coolant (no puddles on the garage floor). How can this happen other than air leaking in from the combustion chamber through a small break in the head gasket? I'm hoping for an alternative explanation. I've bled the system enough to know it's not just a rogue air bubble.

Before starting the turbo project, I had an overnight leak down test and a compression test done at the local BMW indy shop. Both passed with flying colors. When I was driving N/A, I had the same problem and concluded that the air leak was coming from the heater valves as it only seemed to happen when the heat was turned on.

Low and behold, after running about 50 miles with boost and no heat on, it's happened again. When I got off the highway after a test run (video coming), I noticed the temp gauge rising. Never overheated, but went north of the 3/4 mark by the time I got from the interstate to my garage (less than a mile). I bled enough air from the system that my expansion tank is 1/4 to 1/2 inch low. I have no visible signs of an HG problem coming from the exhaust.

I've heard you can test the coolant for signs of combustion gases. Anybody done this before?

cvillebimmer · Post by **cvillebimmer** » Aug 03, 2008 7:17 PM

http://www.troubleshooters.com/tlitthypothesis.htm

Unfortunately, it sounds all too familiar...

Duke · Post by **Duke** » Aug 03, 2008 8:12 PM

OMG...BTDT and bought the $8K T-shirt. You ABSOLUTELY have a head gasket leak.

Period. Just pull the head and replace the HG. Save your time, money and stress by just doing it.

When the head is off, have it checked and also have the block checked for being level.

Kyle in NO · Post by **Kyle in NO** » Aug 03, 2008 9:11 PM

Duke wrote:OMG...BTDT and bought the $8K T-shirt. You ABSOLUTELY have a head gasket leak.

Period. Just pull the head and replace the HG. Save your time, money and stress by just doing it.

When the head is off, have it checked and also have the block checked for being level.

Probably yes, and the head needs to come off to confirm. I wouldn't say ABSOLUTELY though, you swapped gaskets several times and never fixed the problem.

It would be more accurate to say that he's likely getting combustion pressure in his cooling system, and the most common and likely suspect would be the head gasket.

turbodan · Post by **turbodan** » Aug 03, 2008 9:59 PM

Do a HG. Put it back together with some studs. An MLS isn't necessary. Myself and others have done quite well with a stock gasket and studs.

cvillebimmer · Post by **cvillebimmer** » Aug 03, 2008 10:26 PM

turbodan wrote:Do a HG. Put it back together with some studs. An MLS isn't necessary. Myself and others have done quite well with a stock gasket and studs.

Before I started this project I had myself convinced I needed an HG. I subsequently convinced myself that the HG wasn't the problem. This is probably because I was more interested in boosting than I was replacing the HG.

I already have an Elring gasket set that I bought from bave auto and I was going to go with ARP studs. Anything else I should do at the same time?

Can anyone recommend a reliable machinist in central VA?

turbodan · Post by **turbodan** » Aug 03, 2008 10:28 PM

Thats some reckless stuff right there.

These are dangerous games.

cvillebimmer · Post by **cvillebimmer** » Aug 03, 2008 10:31 PM

turbodan wrote:Thats some reckless stuff right there.

These are dangerous games.

Yes, probably. But I kind of stopped guessing after a leak down and pressure test came back clean. I should have gone with my intuition. At least I've never overheated and everything else seems to be okay...

http://www.youtube.com/watch?v=H6yVQlyukDE

So my HG may be bad, but everything else seems okay. The KKK-27 with 745i waste gate boosts to a solid 9psi at about 3k and stays there all the way through 5k.

Here's another...

http://www.youtube.com/watch?v=VKjuHVaNQII

turbodan · Post by **turbodan** » Aug 03, 2008 10:49 PM

You should check with TCD about a new turbo. He might just have a K27 with a GT35R wheel installed sitting around the shop. Thats what you need. Whatever you do, dont put another K27 in there. That car still has a TON more potential.

cvillebimmer · Post by **cvillebimmer** » Aug 03, 2008 10:58 PM

turbodan wrote:You should check with TCD about a new turbo. He might just have a K27 with a GT35R wheel installed sitting around the shop. Thats what you need. Whatever you do, dont put another K27 in there. That car still has a TON more potential.

He does have one, or at least one he can get. We'll see how long I last before I'm willing to cough up the $800. First I need to sort out the cooling issue.

cvillebimmer · Post by **cvillebimmer** » Aug 04, 2008 1:14 PM

turbodan wrote:Do a HG. Put it back together with some studs. An MLS isn't necessary. Myself and others have done quite well with a stock gasket and studs.

What kind of boost are you all running on a stock head gasket?

Post by **Jeremy** » Aug 04, 2008 2:53 PM

cvillebimmer wrote:
turbodan wrote:Do a HG. Put it back together with some studs. An MLS isn't necessary. Myself and others have done quite well with a stock gasket and studs.
What kind of boost are you all running on a stock head gasket?

The stock headgasket for an m30, with head studs, is capable of holding 15psi pretty easily. 15-20psi is a bit of a gray area, results are a bit mixed. Anything over 20psi would not be recomended as the fire rings WILL push out and distort with that sort of cylinder pressure.

I run 10-11 psi non-intercooled with a stock gasket and ARP studs.

Jeremy

cvillebimmer · Post by **cvillebimmer** » Aug 04, 2008 3:06 PM

Thanks Jeremy, that definitely helps. I have no intentions of going above 15 now, in fact, I was pretty impressed with 9psi.

I guess now I have to decide whether or not I'll ever go north of 15. Are there any negatives to using an MLS gasket below 15psi?

turbodan · Post by **turbodan** » Aug 04, 2008 3:33 PM

They can be hard to seal. I wouldn't run one unless its really needed.

My M20 gasket held up well over 20psi. It didn;t blow the fire rings out either. The head was lifting, but the gasket itself looked good.

Brad D. · Post by **Brad D.** » Aug 04, 2008 4:06 PM

If(when?) I have to do a HG, I will be trying a stock gasket with ARP studs on my m30.

cvillebimmer · Post by **cvillebimmer** » Aug 04, 2008 4:14 PM

Done and done. Since I already have the Elring gasket in the garage, we'll start with that.

M. Holtmeier · Post by **M. Holtmeier** » Aug 04, 2008 4:24 PM

Big Bronze Rim wrote:If(when?) I have to do a HG, I will be trying a stock gasket with ARP studs on my m30.

Brad, is yours still running the stock gasket and bolts?

Brad D. · Post by **Brad D.** » Aug 04, 2008 4:38 PM

Yup, stock HG and bolts. Right now at an unstressed 8psi. I plan on upping the boost to 10-12psi, but I haven't felt compelled to put the laptop back in the car and drive around tuning with the AC off in 100 degree heat.

alijonny · Post by **alijonny** » Aug 06, 2008 1:47 AM

quick question, do you have a shroud around the cooling fan? that might be adding to the heating issue and boiling off of coolant... I know i've seen that kind of problem with american RWD cars where there is just not enough cooling going thru the radiator. but on the highway...idunno, just a thought. also, most mechanics should have the HC leak detection device for cooling systems. it's about $70 off any given tool truck, if you live anywhere near my shop, I can check it out for the price of a nice conversation from another M30 folk... lol.

90e34535i · Post by **90e34535i** » Aug 06, 2008 3:16 AM

I think the stock m30 head gasket with ARP studs can hold over 20psi of boost with out distorting the gasket, as long as you don't detonate.

cvillebimmer · Post by **cvillebimmer** » Aug 06, 2008 8:11 AM

alijonny wrote:quick question, do you have a shroud around the cooling fan? that might be adding to the heating issue and boiling off of coolant... I know i've seen that kind of problem with american RWD cars where there is just not enough cooling going thru the radiator. but on the highway...idunno, just a thought. also, most mechanics should have the HC leak detection device for cooling systems. it's about $70 off any given tool truck, if you live anywhere near my shop, I can check it out for the price of a nice conversation from another M30 folk... lol.

I do have the shroud on, just not for the vid of the engine. Before I started experiencing this mysterious coolant loss and air entering the cooling system, the car always held just under the mid point on the temp gauge even in 100 degree traffic with the A/C on.

I wish I could take you up on the offer for the HC detection test, but VA to Indiana is a little far. Thanks for the offer though!

johnnye23 · Post by **johnnye23** » Aug 06, 2008 8:30 AM

I have not used this testerbefore, but for the price it may be worth the investment to confirm what you suspect .

alijonny · Post by **alijonny** » Aug 08, 2008 12:18 AM

yup thats what Ive got! only it says SNAP ON and I probably paid $150 more than it's worth. but it has done some good diagnosing. I have successfully diagnosed 5 head gasket leaks out of about 18 cars tested that I would not have known otherwise. The time I absolutely knew the thing was working was when I did the test on my M30 before removing the head. the fluid color changed from blue to green faster than I ever seen! talk about sinking in the stomach feeling!

MyE28.com

MyE28.com

M30 Cooling System Pressure and Air

M30 Cooling System Pressure and Air

Interesting web article about mysterious overheating

First Video of boosted e32