Will tightening head bolts help on a coolant leak?

[ponderosa]

I have replaced my thermostat in my M50, it was stuck open. Now the damm thing is a steam generator when hot. 151K miles. Hmmm.

I read somewhere that a guy tightened down the head bolts and took care of the problem. It probably wouldn't last anyway.

Have not done a compression test yet - too damn cold in Mich. Looked at my Bently manual. Do I really need all those tools to pull the head?

One more question - How do you guys view Bavarian Engine Exchange?

I really want M power too!

[HoJo]

WTF??? You need to find where the steam is comming from. It might help to let the car cool down so the coolant comes out as a liquid. Tightening the head bolts will most likley not cure your problem. Did it leak before you replaced the thermostat?

[ponderosa]

The steam is coming out the tail pipe. It did not do it before - when the motor was running cooler.

The bolts on the water pump pulley were loose. I'm thinking the water pump went and it was replaced but the head got warped or worse.

I don't want to put any money in a motor with a cracked head. I wonder if there is a test to see if its a bad head gasket.
Hmmm.

1993 325is

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[beeze]

I would NOT simply tighten the head bolts. If you change your oil and you see coolant in the oil, you have a head gasket problem.

[Mark85]

all that will do is snap a head bolt, so be my guest and tighten those suckers down...i'll be waiting for your next thread

coming soon "I snapped a head bolt, help please"

[HoJo]

What's the temperature outside?

Were you driving the car when the waterpump went out, did the car overheat?

[HoJo]

If you really have your doubts there is a test that can detect combustion gasses in the coolant, can't think of the name of it at the moment. Have a shop do it. If there turns out to gasses in the coolant it is most likley a head gasket, it will usially fail before the head does.

[KC Ron Carter]

CO2 detector test will determine if the combustion gases are in the coolant.

The head bolts are stretch torgued and usually are not even reused.

DO NOT TIGHTEN the head bolts.

You need a real mechanic, asking here will not fix that car.

Later,

[ponderosa]

Hey Guys, thanks alot for all your help.

I've been running the car with the outside temp around 40 deg F
The engine runs fine even when it gets to normal temp (guage straight up) untill I take it for a drive. Then some white smoke comes out the tail pipe. When I shut it off then start it back up again it runs a little rough. Still the white smoke.

The cooling system never really has much pressure on it (just a little psss when I remove the cap). Yes I know, NEVER do that!
I do not see a coolant leak anywhere.
No bubbles in the coolant. I have a CO gas detector, I will check
that soon. A compression test too.

This did not happen untill I replaced the thermostat. It drove ok with the temp just above the blue mark. With the new
thermostat it stays straight up and a little white smoke when I drive it.

The water pump was replaced before I got the car. I also found green coolant in the system. Got the blue BMW stuff in there now.

At least the head gasket is shot. The head could be distorted because it only leaks when it gets to normal temp. A crack in the head would do that too, I think. Hmm

I don't want to drive it anywhere to have any tests done, it may damage the head more.

The head must come off!

I'm asking for suggestions from someone with experience with this job please.

What a reasonable charge for a shop to do the work?
Anyone know a good shop in SE Michigan to have the work done?

Thanks again, John D.






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[kaiservon]

Before you just start pulling the head off, you need a thorough diagnosis. What is blue coolant?

[Mark85]

yea it could be a crack that only opens up when hot, ive seen it happen with a plastic coolant tank where it would leak when the tank was hot because the crack expanded and after you stopped the leak would stop too because the plastic cooled down

of course metal works this way too, expands with heat...

[one]

I see where he is going with this.

Blue smoke out the pipe = Death smoke (oil)

White smoke out the pipe = Water in the combustion chamber.

Before hand the car did not have much backpressure nor steam pressure in the coolant line. After installing the thermostat, he is now getting lot's of backpressure and heat and it is forcing it's way into the combustion chamber and showing up in the tailpipe with a telltale sign of water in the combustion chamber (white smoke).

Sounds like a similar problem i had with a waterjacket seal on the headgasket of a different vehicle i had once.

I think you are on the right track with the headgasket idea, but those bolts only torque once, so overextending them will make it worse.

[ponderosa]

Thanks

A thorough diagnosis is really what I'm looking for. I would rather replace the engine than spend thousands on repairing it.

Blue coolant is what the BMW dealer sold me - its blue. I think its free of damaging chemicals. The old antifreeze may have ate away the head gasket.

I'm thinking the head is ok, maybe warped a little. I'm thinking the head gasket is just shot.

If I didn't need all those BMW tools to pull the head I would jump right in.

The car ran ok with the temp just above the blue mark (for 151k miles).

Thanks again