White Smoke From Exhaust

Went for the first real run of the season yesterday. Not a long one, about 15 miles out and back. The road was very washboardy, so mostly 1st and 2nd gear.

We took a side trail that had some very mild rock crawling. Got a little off trail so was turning around to get back on track. While turning around, I bumped up onto a small rock ledge to get more room to maneuver. As soon as I bumped up onto the ledge, I noticed a big puff of white smoke from the exhaust. Not sure if this has anything to do with the smoke or just a coincidence.

It smoked slightly all the way home, worse upon accelleration. I checked oil and coolant when we got home, but there was no noticeable change in fluid levels.

It has never smoked before this trip. I checked some of the other "white smoke" threads and they talked about the PCV valve. I will check that today.

Any other ideas? Hope it is not the head gasket.

Thanks for your input.
Steve

 

My rule of thumb…

Black = rich fuel mix.
Blue = oil burning
White = water/coolant

If white smoke persists, possibly the head gasket is leaking, or something like that.

I would take a look at the plugs, see if any are oily, sooty, or wet. You could run a compression test at the same time.

 

White "smoke" is coolant. Condensation out the exhaust from burning water/coolant. There is usually a slight sweet smell if antifreeze.
-Donny

 

somebody blew a head gasket....

 

Thanks guys. Every once in a while I would get a whiff. It wasn't sweet smelling. More of an exhaust smell like when the carb is running rich.

I will pull the plugs in a bit and see what they look like. Need to dig out the FSM and see where the PCV valve is located. I just looked at the engine and it isn't obvious.

 

That's what I am thinking too.

 

I had this happen on my cj3a. The vacuum part of the fuel-vacuum pump failed. Whenever Ithe passenger side of the Jeep was higher than the driver's side, oil would get sucked onto the intake and make a huge cloud of "running rich smell* white smoke.

It was obvious when I looked through the carburetor into the intake manifold...lots of oil in the intake.

 

So.....I started the jeep again today (cold engine) and no smoke. Thinking maybe it needs to warm up enough to open thermostat before it starts smoking? My wife saw the smoke too yesterday, so I know it wasn't my imagination.

Going to try to clean things up a bit before I start checking stuff.

Also...is it possible I don't have a PCV valve? I see nothing on the valve cover. There is a hose from the dipstick tube to the air cleaner horn just before the carb. Nothing that I can see going into intake manifold. There is a plug below carb and above distributor but it looks awful small for a pcv valve to go into.

 

On many F-heads that manifold plug was tubed down to a T at the front of the engine. One leg went to the PCV valve on the intake valve cover, the other leg to the vacuum pump (w/oil pump).

An occasional rare episode of smoking, which clears up, can sometimes be an irritable valve seal, or a stuck piston ring.

 

Just finished compression test...cold engine (didn't have time today for a warm up drive).
Tested each cylinder 2 times for comparison.

Cyl 1...110...115
Cyl 2...110...115
Cyl 3...120...115
Cyl 4...100...115

All spark plugs were black and sooty. Will grab some new ones when I get a chance. Plug #4 had some carbon buildup on the electrode but I could scrape it off with my thumbnail.

 

See if you can get a hand on a cooling system pressure tester to see if it leaks down when sitting or if pressure spike while its running from exhaust gasses. Those compression numbers look fine. Other than that, drain the oil and let it separate a few hours and see if you have water in it. If not, watch the coolant level and if all is good, love the jeep for what it is. That's what I would do.

 

Good plan.

 

Thank you all. Sounds like I dodged a bullet. Guess I will drive it and keep an eye on things for awhile. I will drain and check oil next weekend.

Thanks again.

 

You may have had water pooled in the muffler that flowed to a hot part of the exhaust when you bumped the rocks.

 

That may be possible. We had been easing downhill for a while.