Blown head gasket? Coolant tank pressurized after sitting over night...

[DocWyte]

Was at Pueblo Motorsports Park this past weekend and had a good day. Temps were high (90-95+) but water temps on the car never went over 215-220 on my aux gauge. Thought all was well.

When I got home the car (1998 M3) sat on the trailer over night, then I moved it into the garage. OBC said "low coolant", so I turned the car off and checked it and it was low.

Waited until the afternoon for it to be cold and I started to remove the overflow cap. To my surprise, it was still pressurized. Coolant level popped up to the "Kalt" level once the pressure was released, before it was almost to the bottom of the tank.

This means bad head gasket right? Motor has ~87k miles on it, stock head gasket as far as I know. Any thoughts?

If it is a bad head gasket, what's the "While I'm in there" jobs I should do?

I'm thinking Victor Reinz head gasket and associated seals/gaskets, ARP head studs, rebuild the Vanos, have the head checked at a machine shop and replace anything bad and maybe do a set of cams. Anything else

[TXBDan]

Not necessarily. I'd check the oil and coolant for contamination, compression test and a combustion gas test first to help diagnose first. Have you ever bled the system while hot? I'm convinced doing that will show these symptoms since it equalizes the pressure while the coolant is expanded so when it cools it creates a vacuum.

http://www.bimmerforums.com/forum/sh...g-thread/page2
Check out post #49

Elring supposedly makes the best head gasket.

[DocWyte]

I just rebuilt the cooling system 2 weeks ago, so just bled it. Had the nose in the air, engine running, slowly added coolant until all the bubbles came out and had hot air out of the vents. Bleeder closed, cap on, turned car off. Heat cycled the car several times, waited for it to cool, added coolant to the "Kalt" line as necessary. Didn't have a pressurized overflow tank then, which was only 1.5 weeks ago.

Took it to the track last Saturday, ran the whole day, coolant temps under control, then when I got home and pulled it into the garage got the "low coolant" warning, etc.

[jayjaya29]

The great disappearing coolant trick. Many others, myself included, have had the same thing happen with our cars with no effect on the performance of the car.

[DocWyte]

Yeah, car ran all day at the track fine and didn't overheat, even though it was very hot out and I was hammering on the car.

Forgot to say I heat cycled the car in my garage several times, letting it completely cool and adding coolant to the "Kalt" line until the coolant level stabilized. At that point I figured all the air was out of the system and the tank wasn't pressurized any of those times.

[jrkoupe]

many here know more than me but let me add this:

95 s50 in my e30....for 8 yrs or so...


she NEVER overheated but man she would develop pressure in the system..hoses rock hard.....cooling res burped....but all this only after 20 min track sessions..........never ever on the drives to/fro the track.

negative results to sniff tests........


no milky oil.....all nada.

turned out I had a seeping HG and a bit of a warped head.....needed like a 009 shave...but only hi rpm track work revealed all this

[DocWyte]

That's what I'm afraid of, that this is the warning shot across the bow so to speak...

[jrkoupe]

yup

and oh every1 swears by the Elring HG..I used one...but they can be hard to find.
I used new oe stock head bolts......I wasnt convinced ARP items would matter.....

[olemiss540]

That's what I'm afraid of, that this is the warning shot across the bow so to speak...

Correct. Good time for cam upgrade, arp studs (highly recommend), vanos rebuild, heater core hoses, clean icv, replace manifold gaskets and vacuum hoses, plugs, retainers (if s50).

Had same symptoms and headgasket (elring ONLY) fixed it.

Sorry for your recent luck!

[DocWyte]

Bogus! Oh well. At least I have 5 weeks before my next track event, so hopefully this can get fixed in time. It's only money, right?

[jrkoupe]

oh fo sho....


new retainers

[SamGrant951]

Same thing as my recently sold Byzanz M3, had more miles than you though. It ran great, never had high coolant temps, no coolant/oil mixing, no external leaks, passed hydrocarbon sniff test but if you drove it and parked it / walked around it would smell a bit like coolant...also hoses were always rock hard and popped off a hose once or twice on track. Got the low coolant warnings as well but if you released pressure it would bounce right back up.

Head was warped a bit, rebuilt that (Elring HG!) and re-did Vanos and good to go.

Also consider doing the oil filter housing gasket and replacing the starter while its all apart.

[DocWyte]

Just replaced the starter, but can add the oil filter gasket to the list...

[pbonsalb]

For track people, consider adding an S54 oil filter housing with Bimmerworld AN adapter and running an oil cooler. Could reduce thermal load on the motor. But it is probably also within the realm of normal for a HG to go on an iron block aluminum head motor after 20 years.

[DocWyte]

Yeah, an oil cooler is a good idea. I hadn't put one in as my oil temps were actually fairly low, but lowering them will also lower the water temps. If I have to have the head removed it makes sense to add the oil cooler now.

Gotta scare up an S54 oil filter housing used....

[olemiss540]

Yeah, an oil cooler is a good idea. I hadn't put one in as my oil temps were actually fairly low, but lowering them will also lower the water temps. If I have to have the head removed it makes sense to add the oil cooler now.

Gotta scare up an S54 oil filter housing used....

I have one.... Also might have an oil cooler/lines as well but less certain on that one. Send me a PM if you are interested.

[DocWyte]

PM sent

[RyanC]

Josh, you should either give up on cars, or just buy a brand new Yaris and race that.

[DocWyte]

Says the guy who's on his what, 6th motor in his race car in the last 3 seasons? In comparision I'm doing pretty well! Having the car towed to BimmerHaus tomorrow am, I'll let Jim Leithauser see what he thinks.

Tank still had some pressure in it today, so I'm expecting a head gasket job. What's curious is the car never overheated, not even came close...

[darbyfam]

Had a similar issue on my S52 and it turned out to be a failing HG. It wasn't failed, but allowed pressure to blow by.

[RyanC]

Says the guy who's on his what, 6th motor in his race car in the last 3 seasons? In comparision I'm doing pretty well! Having the car towed to BimmerHaus tomorrow am, I'll let Jim Leithauser see what he thinks.

Tank still had some pressure in it today, so I'm expecting a head gasket job. What's curious is the car never overheated, not even came close...

3rd motor, and I bet I still have less into the rebuilds than you do repairs this year

[DocWyte]

Doubtful, as so far I've only spent $800 having to rebuild the cooling system after the motor mount debacle.

Granted if I do cams with this head gasket job that's gonna cost me some serious $$$. Pretty sad that a job like this (with the cams) will cost me 50% of what I paid for the entire car. Which still should be less than what you spent to rebuild 3 motors. Unless you're getting some serious deal, like $1000 rebuilds....

[Jab31169]

Yea it's the gasket on its way out. Currently rebuilding mine. See here: https://www.bimmerforums.com/forum/s...-Screw-Edition