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Coolant vapour from exhaust manifold

Funkee

Active member
Joined
Feb 19, 2010
Location
Netherlands
1995 940 B230FB

Since a couple of days I notice smoke/steam coming from under the hood.
Figured it's just a leaking radiator but tonight I had a better look and it seems it's coming from the exhaust manifold area.
Problem is I can't really see where it's coming from exactly.

Had the car on the lift and ruled the turbo side out, the water banjo bolts are dry, but there's coolant on the cold side.
When I tried to find the leak with a small mirror (between exhaust runners 1 &2) the mirror gets fogged right away so can't have a good look. Directly explains the coolant hanging off the turbo cold side; just vapour getting it wet I guess.
Also holding the mirror between the exhaust runners 1 & 2 seemed to block the vapour going towards the turbo.

So it seems it's coming from either a leaking exhaust gasket but it doesn't sound like that. Also it would need the water to get into the exhaust port in the head in the first place, but there is a lot of vapour coming out of the back of the exhaust as well.
It (the vapour) also seems to be coming out under pressure, not just leaking on the manifold, but I can't feel where it's coming from cause I can't get my hand in there.

On the other hand it maybe could be a freeze plug, or maybe a warped head/leaking HG to the outside? I never had it overheated but it ran on very little coolant a couple of months ago.

There's no pressure in the cooling system, no gooey stuff, just nice and pink coolant.
It always liked a good taste of coolant though (about 1L every 2000kms), but I always thought it to be a small leak somewhere.

I know it's really hard to tell whats going on based on the story, but maybe someone dealt with this one before.

Video of the ordeal: https://youtu.be/njk8LtvRjA4
 
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Well, I have had a few Volvo engines leak coolant around the area of number one and two exhaust ports. It is the head gasket having corroded around the area of the front of the engine.

Let the engine cool off and use a coolant pressure tester to pressurize the system. You will see where the coolant is coming from. If it still eludes you. Then buy the tracer dye kit and use that to see where the UV trail comes from.
 
Thanks, it may very well be then. Think I'll go with a HG replacement and see what happens.
I kinda was looking for an excuse to buy another 940 or 960/V90 but some issues aside this might be the best car I ever owned - might better stick with it :)
 
Most B230 engined 240 I've had needed a head gasket eventually. I bought my 93 wagon with a blown head gasket at 230k miles. The leak was directly under exhaust number one. I pressure tested it and it peed right out of the engine there.

Head gaskets on these engines aren't that bad. I'm now over 400k miles with the same engine and wondering if this engine will need a head gasket again. lol.
 
^^ Sounds like that is a common failure point. Greg_ervin has a 940 that he kept loosing coolant from and couldn't figure out where it was going. One day, it got on the exhaust manifold and he could smell it. He thought it was the water pump and replaced that. It didn't leak after that, as far as he could tell. Then, one day it was leaking again. It turned out to be erosion of the gasket from the water port all the was to the outside of the head/block outer surface. No wider than a razor blade. It would plug with cooling system debris and be fine for awhile, then, leak again.
 
I've had this happen a couple times over the years. First time was a cracked head, second time was the HG. Have your head pressure checked and then milled before you bolt it back on.
 
Not sure if I have it milled. Don't have the time to wait for a machineshop and did a couple of HGs before without need for milling.
I'll measure first, if it has to be done i'll have it done ofcourse.
 
Not sure if I have it milled. Don't have the time to wait for a machineshop and did a couple of HGs before without need for milling.
I'll measure first, if it has to be done i'll have it done of course.



At least have it pressure checked. It would suck to do a HG just to find out the head was cracked.
 
^^ This, and skimmed/milled, IMO. I won't put one back together without doing those operations. By now, the surface has so much erosion it isn't worth the risk. A straight edge won't pick that up.
 
So to elaborate how I took care of the problem; I took the easy route and bought a 'fresh' FK engine.
A couple of days after my previous post here it started clacking real hard and puking out a lot of steam at the exhaust manifold area.

When I took the exhaust manifold off of the old engine I noticed there where multiple cracks. So the steam wasn't probably coming from the HG but just from the exhaust manifold.

25673429337_3299e733a7_c.jpg


I bought another seemingly cracked manifold which the seller said to be good and put it on the 'new' engine, hoping it was good.
Turning it over the first time it started right up, nice and quiet :)

For now I have a running engine again, and I think I'll rebuild the old one and have the head completely done.
Thanks for the advice anyway :)
 
No, I think a cracked HG (or head) which caused steam in the exhaust circuit -> pressing it out through the cracks. Wasn't spewing coolant though but it consumed some.
 
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