willysmjeeps.com

1953 M38A1, stock F-134

Changed my oil today on this project that I picked up. I put in 15w-40 and a quart of Lucas Oil b/c I had seen some blue smoke at startup while it was running. I've had good luck with that in the past and it seems to have helped this time, as well.

However, I still have just a faint puff of white smoke in the exhaust. When I was changing the oil (which was who knows how old and the jeep had been sitting outside for several months, I believe), I didn't notice any water or coolant in the oil but I did notice some white foamy goo on the dipstick and inside the oil filler tube. As far as I can tell, there is no green tint to it (cooling system is full of fresh 50/50 coolant/water).

What is the best way to diagnose condensation vs. a head gasket issue?

The other problem I have, which I don't think is related, is that the radiator "steams" whenever the thermostat (new) opens up and and starts pumping water/coolant through it. There are no obvious leaks and the engine never gets hot, so I'm thinking it must just be seeping a little and gets worse when it gets pressurized. I'm going to take it to a rad shop, but I thought I'd just throw that out there in case it could be related.

One other thing, I took a look down in the filler tube and there appears to be some moisture dripping down in there from the PCV hose (or whatever that hose is that runs from the top of the valve cover to the filler tube).

That wouldn't seem to be engine coolant as I wouldn't think it would sling it up through that PCV fitting from the valve train, so I'm guessing that's condensation (and it doesn't appear to contain any green coolant). I guess I need to pull the valve cover and see how things look.

Also, since it sat for so long, would it be beneficial to get it out and run it pretty hard and hot for a while to work out some of this moisture? I guess I need to get my radiator squared away before I can do that.

This is the time of year to take it out and run it for a good long run. with these low temperatures condensation forms and you especially find it in the oil filler tube. The only way to clean it up is change the oil and get it out for an hour minimum on the road.
Does the white smoke in your exhaust smell like antifreeze? Hold a white piece of paper to the exhaust until it gets wet then give it a whif. Again, it is going to take a while to get the condensation out of your exhaust.

If you are really concerned with a head gasket leak start with a compression test.

Do a leakdown test, it will pinpoint the cause and headgasket condition. Sometimes compression test will show that there is no serious problem, but you can listen to the escaping air if you do a leakdown test at the source of the problem eg next cyl. valves etc.

Good ideas, guys, thanks. I didn't notice the sweet smell of anti-freeze in the exhaust, but I'll give it another whiff today followed by a compression test and a leak-down if that doesn't tell me anything.

I'm probably overreacting but I don't know anything about the history of this particular motor so I'm keeping an eye out for any little problems that may crop up.

Also I would monitor the coolant level. I read online that your plugs may have a red or green tint if you are burning coolant. Get it out and run it for half and hour and check the plugs.

Coolant in the oil is a very bad for bearings. If there is enough coolant in the oil, you can see changes in the color (greenish tint) and you may detect oil in the cooant (an oily sludge). Open the crankcase drain plug slightly and see if any water/coolant drains out - water is heavier than oil and after a period of sitting, will settle to the bottom. If there is significant coolant in the oil, don't run the engine! Otherwise a good long run with the engine reaching normal operating temp will help purge the system of condensation. If you are uncertain about the cooling system integrity, a good rad shop will be able to diagnose and help fix the problems.

Well, feeling a little better as of now. I checked the old oil I had pulled out and checked the coolant and didn't see any water in the first or oil in the second. I got it up to temp at high idle for about 30 mins and burned off all the overnight condensation in the exhaust. Then, I held a piece of cardboard up to the exhaust for a couple minutes and there was no moisture whatsoever. I guess the light smoke I'm seeing is more likely blue than white. I haven't rebuilt the carb yet, either, so I suppose it could be running pretty rich and contributing (although the smoke is not black).

Still need to do a compression and leak-down test, but I'm not as concerned about coolant as before. Now, how hard is it to re-ring these engines?

Compression test was good. 125 psi dead even across the board. The #1 spark plug was loose in the socket. That certainly couldn't have been good. Tightened everything up and it's running fine. Still a little smoke, though.

As far as the cooling system goes, the "steaming" problem has stopped for the time being. I've been through several warm up and cool down cycles today and it seems to have stopped. Not sure what was going on there, maybe I had it too full or maybe all the air finally came out of it. Guess I'll keep an eye on it and see what happens. Coolant level has not dropped at all.

Sounds like a lot to do about nothing, but was worthwhile to check.
White smoke is generally caused by very cold operating conditions & is not abnormal.