Bought this the other day. Previous owner, Said it had a bad head gasket, no water in the oil. Said it smokes white for a while but quits after warmed up. When I went to pick it up. It worked as stated made a significant amount of white smoke ( steam ? ) and once warmed up it quit doing so. It made the 3 hour drive home with no event. Today I fired it up and did some errands, however I did not get the same amount of smoke( steam? ) Runs strong, lots of zip, 185,000 on it.

might there be another explanation ?

 

A leakdown test will let you know if head gasket has failed. You could do first test with engine cold. If any cylinders failed, you could test them again with the engine warm to see if gasket integrity improved.
Coolant bubbling in the radiator filler neck is another test you could try.

 

Rent a block tester (free when you return it) from the auto parts store. It's a sure fire way to know. Coolant won't always have water in the oil. Usually the coolant leaks into the cylinder and blows out the tailpipe, hence the white smoke.

https://www.google.com/search?q=how+...qqtsP8tq1sAI15

 

Bought the block tester, and it appears to confirm.

 

How long can I run it like this before I actually have to do the repair?

 

Crap shoot. Might run like that for years, or, it might get worse, contaminate the oil, and trash the engine tomorrow.

 

Did you remove some coolant before running it? If it sucks up coolant, it gives a false reading.

Like HeyYou said, it's a crap shoot. How much coolant are you losing? The cylinder/s where the coolant is going will see extra wear over the others. I had a small HG leak many years ago and fixed it 'chemically.' Had to do it twice to overcome the learning curve, but it worked on the 2nd try. Cost me like 40 bucks and some coolant + time. I had nothing to lose cause I wasn't going to invest HG replacement money at the time. Driving it daily since then with no issues.

 

I did not drain any coolant, but I wondered about that as where the fill cap is, also appears to be the overflow. Right by the fill cap is where a hose plugs in. I start it up and stick my finger down where the hose is and what sprays out appears to be part fluid and part gaseous. The first few times I pumped the bulb no reaction but after about the 5th pump the fluid started turning yellowish, so I was concerned whether I sucked some fluid in there and contaminated the process. I supposs if I drain a couple quarts out, then it would only be gaseous flow through the hose. This cooling system has me wondering though if its like this old 80's Waggoneer I had, where you had to keep pouring fluid in it through the overflow with it unpressurized until the coolant expanded enough to back flow, then you could top it off and cap it. You couldn't just top off the radiator as it didn't have a cap, and you couldn't just top off the overflow because it wouldn't get enough coolant in it. I'm wondering if this one works the same way.
I have not yet had a noticable use of coolant so far.

 

How do you fix it chemically? new one on me.

 

Thought about just torquing the head bolts a bit more to squeeze the HG down, but by the time I took enough stuff apart to get to them, I might as well just do the job.