Question regarding blow-by following engine rebuild

[marcin]

I had the engine in the 5020 rebuild last year, the head was machined and checked for cracks. I noticed working on the tractor a few days ago that there was white exhaust coming from the blow-by tube - is that normal? Also, I feel like I can smell coolant from the exhaust - I am not sure of this but it smells kind of sweet?

I would really appreciate your input on this. Should I have the mechanic look at this again? Thanks

 

[s219]

Check the oil -- is it milky looking, like coffee with cream?

 

[beenthere]

And yes, have the mechanic look at it as it may be a result of his/her work. As well, do as s219 suggests and see if there is water in the oil i.e. milky

 

[marcin]

The engine oil color appears normal: dark brow/ black.

What could be the cause of this?

 

[buickanddeere]

Which 5020 and how much of an overhaul was the rebuild ?

 

[marcin]

It is a 1967 5020 (SN 19K)

I think it was a complete overhaul: the tractor was split, head was machined, sleeves and rings were replaced, front and rear seals replaced, etc. I remember seeing the crankshaft out. I am not a mechanic, but I think apart from boiling the block, there wasnt anything else to do.

 

[AKfish]

How's the radiator/coolant level? Steady or dropping?

Could be a leaking head gasket or a cracked cylinder head... Or I have noticed white smoke from the breather tube with the right ambient temp/humidity conditions.

As was mentioned, have a shop take a look at the tractor. The folk's with the overhaul should be willing to stand behind their work if not many hours have been put on the tractor since they worked on it.

 

[marcin]

The radiator coolant level does seem a little lower, maybe 2" from the top. The head was pressure checked at the machine shop and found to be fine. Could the gasket fail in less than 50 hours? What's the deal?

 

[AKfish]

The radiator coolant level does seem a little lower, maybe 2" from the top. The head was pressure checked at the machine shop and found to be fine. Could the gasket fail in less than 50 hours? What's the deal?

Short answer, yes. Was the head planed/resurfaced and oversized gasket installed? If not, maybe the head has some warpege. If yes, appropriate torque sequence as well as recommended ft/lbs might not have been properly completed.

Or just a defective head gasket...

 

[Plantation Paul]

How many hours since the rebuild? A bit of blow by, especially on those older tractors, is normal. If it was getting water in the cylinders, you would be having more problems I believe. If the water was entering via a head gasket leak, it would be leaking compression into the cooling system too, I would think. Unless there is a crack in an intake port and the pressure test should have caught that. Talk to your mechanic and ask his advice. He may have a pressure tester that he can check the cooling system for leaks.