751 - white smoke, coolant in cylinder, high compression

[rook]

Wondering if anyone has any thoughts on my situation. Something's amiss but I can't wrap my head around what's going on. I'll be pulling the head and it may become obvious then, but interested in thoughts. 751 with v1903-e Kubota. 1500 hours, hasn't overheated. Was getting white smoke out of exhaust at idle, but would go away when given throttle. Ran good, maybe a little rough at idle, but not always. Ran a block test in the radiator and it tested positive for exhaust gas in the cooling system. Ran a compression test and all cylinders had right around 600psi compression. Cylinder 1 though was spitting out a good deal of coolant as I tested the other cylinders. I saw somewhere the compression spec for a v1903 was 540psi, but dealer checked the fsm and said should be 430-470psi. I'm wondering how compression would get so high across all cylinders, and how it held the compression in cylinder 1 with the coolant getting in? Any ideas are much appreciated. I'll be tearing down soon.

 

[antfarmer2]

Hope just a head gasket and not a cracked head

 

[rook]

Hope just a head gasket and not a cracked head

That's what I'm hoping. I was surprised that either would go though based on hours and never overheating it. Any idea on why the high compression, and consistency across all cylinders?

 

[antfarmer2]

That's what I'm hoping. I was surprised that either would go though based on hours and never overheating it. Any idea on why the high compression, and consistency across all cylinders?

Small leak and the coolant helps to plug it

 

[Tazza]

That's what I'm hoping. I was surprised that either would go though based on hours and never overheating it. Any idea on why the high compression, and consistency across all cylinders?

That is very high compression, it does sound like a crack or blown gasket.
If the valve clearance was out, it could give higher compression i guess. I thought they were mean to run around the 500 mark, i bet is starts easily

 

[rook]

That is very high compression, it does sound like a crack or blown gasket.
If the valve clearance was out, it could give higher compression i guess. I thought they were mean to run around the 500 mark, i bet is starts easily

Interesting, thanks for the thoughts guys. Small coolant leak sealing compression, could be. My thought was any leak that would let coolant in, would surely let air out at 600psi, but I'm not a terribly experienced mechanic, and have not worked on diesels. My only full rebuild was on a gasoline engine. I expect to be surprised and learn something new when I take it apart. The valves have never been touched that I'm aware of (don't know the history before 600 hrs), so I'll have to look into adjusting those. I wonder the likelihood of a crack between a cooling jacket and valve up in the head that doesn't extend all the way down to the combustion chamber? I'd think it'd typically crack bottom up though.

 

[rook]

Interesting, thanks for the thoughts guys. Small coolant leak sealing compression, could be. My thought was any leak that would let coolant in, would surely let air out at 600psi, but I'm not a terribly experienced mechanic, and have not worked on diesels. My only full rebuild was on a gasoline engine. I expect to be surprised and learn something new when I take it apart. The valves have never been touched that I'm aware of (don't know the history before 600 hrs), so I'll have to look into adjusting those. I wonder the likelihood of a crack between a cooling jacket and valve up in the head that doesn't extend all the way down to the combustion chamber? I'd think it'd typically crack bottom up though.

It does fire right up! In the non winter months in Northern MN anyhow...

 

[Stephend]

It does fire right up! In the non winter months in Northern MN anyhow...

the high compression in the cly maybe be due to carbon buildup or if there has been leak mineral buildup. Might try a fuel additive to see if it will redude the buildup.