L345 - V1501

[Ku-boat-a]

Hey all,

I own one of those ocean tractors. The V1501 - 56498 block with the Universal conversion 5432 on a boat.

I’m a novice but I’ve done a a fair amount of work on the engine myself over the years. I’m starting to tread water with this situation.

Appears there is oil in my coolant reservoir tank. Yet to see any coolant in oil. but loss of 30% on dipstick after 4 hours of running. No “milkshake”.

Ran a compression test. 380/390 across all. Tested cold and not WOT(my mistake).

My first cold leak down test (ever), believe I was at TDC, @80psi showed:

Cylinder 1 - air intake lite, exhaust lite, dipstick no, crank case slight,
Cylinder 2 - air intake good amount of loss, exhaust lite, dipstick lite, crank case lite
Cylinder 3 - air intake good amount of loss, exhaust lite, dipstick ever so slight, crank case lite
Cylinder 4 - air intake good amount of loss, exhaust lite, dipstick no?, crank case slight

Did not see any coolant bubbles from leak down test.

Thanks in advance for any help diagnosing this!

 

[North Idaho Wolfman]

Oil in coolant is almost always a head gasket issue.
It's like a 90% chance that's where your problem will be.
The other issues almost always require major parts replacement.
Your better off replacing the engine at that point.

 

[Ku-boat-a]

Oil in coolant is almost always a head gasket issue.
It's like a 90% chance that's where your problem will be.
The other issues almost always require major parts replacement.
Your better off replacing the engine at that point.

Thanks for the reply. Ive read a number of your posts on here and appreciate your approach and knowledge of these.

Im unfamiliar with the passageways for the coolant and oil. Assuming it was a crack in the head / gasket and good compression…do you know where it could be that only oil is entering the coolant?

Am I correct that there is no oil cooler in my setup? Its my understanding those are external, which i don‘t have.

 

[North Idaho Wolfman]

Thanks for the reply. Ive read a number of your posts on here and appreciate your approach and knowledge of these.

Im unfamiliar with the passageways for the coolant and oil. Assuming it was a crack in the head / gasket and good compression…do you know where it could be that only oil is entering the coolant?

Am I correct that there is no oil cooler in my setup? Its my understanding those are external, which i don‘t have.

There is a feed pipe that goes from the block to the head and that has a sealing O'ring and if that seal goes bad it can cause pressurized oil to be forced into the collant, without coolant getting into the oil.

Another way would be a front gear case issue, that one normally will do coolant into the oil, and not oil in the collant.

Are you sure there is not an oil feed and return into the coolant exchanger?
Some marine systems have that.

The other option is a head crack or a block crack, they are harder to find.

 

[Ku-boat-a]

There is a feed pipe that goes from the block to the head and that has a sealing O'ring and if that seal goes bad it can cause pressurized oil to be forced into the collant, without coolant getting into the oil.

Another way would be a front gear case issue, that one normally will do coolant into the oil, and not oil in the collant.

Are you sure there is not an oil feed and return into the coolant exchanger?
Some marine systems have that.

The other option is a head crack or a block crack, they are harder to find.

I‘ve attached a couple, fairly accurate, drawings of how the cooling is configured on this.