JD 1020 head gasket leak - questions

[Figato]

I noticed that my JD 1020 coolant is always about 1 gallon low.
So I tried filling it up, but then started getting a lot of smoke out of the blowby tube (or whatever it's called).
I also noticed that my freshly changed oil had water in it.

So what I'm thinking is that the head gasket is leaking and coolant is getting into the crankcase.

A few questions:

Does this sound like a head gasket leak?

How difficult is that to change out on a JD 1020?

How long can I get away with putting the job off? I run the tractor for maybe 20 hours / year just to maintain my hunting property and put in food plots.

Thanks in advance.

PS - Diesel - about 7,000 hours

 

[KYErik]

Cavitation is another possibility- If your engine has wet sleeves and has a lot of hours, it could be that cavitation forces have drilled through the lower parts of the sleeve allowing coolant into the crankcase. This happened to my dad's JD 2840 6 cyl diesel engine.

Regardless of the source, coolant in the oil will damage the main and rod bearings very quickly. You really shouldn't keep running it unless you plan to also replace all of the internals i.e. do a total rebuild.

 

[Farmerford]

Most likely a bad head gasket or perforated cylinder sleeve. In either case, as KYErik said antifreeze is deadly to crankshaft and rod big end bearings. If you just want to limp along then it might work to use water only as coolant (obviously draining when not using) to keep antifreeze off the bearings and leave the radiator cap in nonpressurized position to minimize amount of water forced into crankcase. If running with the water low reduces the leakage into the crankcase, then leave it low unless it overheats.

The risk of doing this is that without antifreeze and supplemental coolant additive (SCA) you risk cavitation damage to the wet cylinder sleeves as KYErik mentioned if that is not already your problem. But I don't view that as a major risk because it probably makes sense to replace the sleeves anyway if you go into the engine to replace the head gasket.

But if you are reasonably mechanically inclined the head gasket alone can be replaced with normal hand tools in a few hours: combination wrenches and socket of 7/16 through 3/4; a torque wrench; Allen wrenches and feeler gauges to adjust the valves; carburetor cleaner, brake cleaner, and a wire brush to clean the carbon off the block and cylinder head. The hardest part will probably be getting out the exhaust manifold bolts because the hex heads will have rusted to round blobs.

Replacing cylinder sleeves is quite a bit more involved.

Keep us posted.

 

[Figato]

Thanks.

When I got it the antifreeze level was low, and the oil was black so I think the previous owner knew of the problem and just ran it like that.

As I was finished cutting the grass (about 2 hours) there was no more steam coming from the blowby tube and the antifreeze level was down. That's when I discovered the milky oil.

Come spring when I start her up again, I think I'll throw a bunch of bar's leaks into the radiator and drop the oil. Run it a bit and change oil and filter, then see how long I can push it.

My main problem is that my hunting land is far from my home. If I had her in my backyard, I'd make it a winter project.

-- added

Quick question: Would cavitation cause a loss of compression? I don't see that as it doesn't burn any oil that I can see in the exhaust.

 

[KYErik]

Cavitation may or may not affect compression, depending on how high the hole is on the sleeve. If the hole was low (below the level of piston ring travel) it would not affect compression, but if it was high- yes it could (and it would also result in lots of exhaust gasses entering the coolant forcing coolant out of the pressurized rad cap).

 

[Figato]

Update:

I bought Bar's leaks head gasket fix (about $30). It's the stuff that you don't have to drain to use.
Pour in and go.
It worked. Radiator now holds fluid without a problem...
But - I think I found the problem.
A big patch of JB weld on the side of the engine block from the previous owner.
Must be a cracked block. Pretty sure, though I have to say, I'm impressed by the repair.
No smoke, full power and starts right up. Pretty good for a $3.99 repair.

On another note - how much to drop a rebuilt engine into the ol' girl?