Hey folks, about a month ago, the wife left the vehicle idling as she ran into her parents house (well about 15 minutes). It was probably 95 degrees out. When she came out the jeep was no longer running. had popped the upper radiator hose and overheated enough to shut down evidently. replaced hose and thermostat and has been running fine, but would get a little warmer when idling at a light or whatever at times. i attributed that to the heat outside. been a little cooler outside and has not been getting as warm.


today I have noticed white smoke on startup 3-4 different times. Once for like 2 minutes until I revved it a little and it cleared up. My concern is that I am low on coolant for the second time in month. had to add bout 1/2 gallon. It is not running rough, drove 200 miles today. I have started it three times this evening and had white smoke twice. once pretty constant til I revved it. The oil looks normal, no milky look, and is on level where it should be. Can a blown head gasket cause intermittent smoke and not running rough?

 

A little more info would be helpful. Year, engine, transmission etc. From the sounds of it you might have a blown head gasket. You wouldn't happen to have an '00-01?

 

It can...are you leaking from a hose maybe

 

Dang, can't believe I didn't post that

92 cherokee 4.0 HO 4x4. 172k. Tranny, I don't know.

 

Did you do the tail pipe taste test ?

 

well, not literally. didn't have a whole lot of smell to it though

 

could have a crack in the head or the head gasket is bad.........

 

So from what I hear, it doesn't necessarily have to show up in the oil. Straight into the chamber and burns up. Don't really notice after running a minute, but I know the coolant is going somewhere. Should I stop driving it like, now? What am I looking as far as cost to have a mechanic replace the head gasket? Or maybe I can do it myself, I do quite a bit of my own work.

 

Although it looks like a daunting task, replacing the head gasket is fairly easy with general hand tools. I'm certain that there are write ups on here that you could turn too for "how To", or even purchase a repair manual. In my shop the repair would run about 1500.00 between labor, misc parts and machine shop labor/parts or if you do it yourself, around 200.00 should cover it. However prices on parts and labor change dramatically depending on where you live...

 

A wet/dry compression test might be a good start. Yea, if it got so hot it died and you are steaming and loosing coolant you might well have issues with the head, head gasket.

A fast easy check, if you top it up, then "power-brake" it with the cap off, you might see bubbling or even a geyser. Won't necessarily tell you that it's good, but it can be pretty clear if it's bad.

The job can get a little though, it would be nice if you had somebody to lend a hand who has been there...at least to call.

 

blown head gasket, warped head

 

Not necessary to taste the exhaust.
If you rub your finger on the inside of the pipe and it feels slimy, there is a problem.

 

Thanks for the replies. Will do a couple more checks and go from there. Maybe just a head gasket and not a head itself. On the other hand a new head might be nice if it would quieten the ticking......

 

Or we have a new Pope.

Yeah, ok...stop with the tomatoes already.

Sure, head gaskets can blow with only a somewhat minor coolant leak into a combustion chamber, they aren't always catastrophic failures. If you pull your plugs and find one or more that has been steam-cleaned, that's exactly what's happened.

If you do decide to change it yourself, check the head with a straight edge and feeler gauge to make sure it hasn't warped. If you can't fit .004" under there either lengthwise or corner to corner, you're good.
It's uncommon with the 4.0 (and the block almost never warps), but check anyway. Any severe overheat is suspect and it beats having to re-do it.

 

Gonna pull my plugs and take a look at them later.

#1- The jeep does not miss

#2- I only really notice it on startup, even when fully warmed, if I shut it off and start it back, will get some steam. from tailpipe but will seem to clear when getting the engine up to speed.

I just assumed a head gasket would cause somewhat of a miss or rough idle. Is it possible that the leak is so small, that it wouldn't affect the idle or running?

I know the coolant is going somewhere and do not see a leak. And seems to get a little warmer than usual at idle.

Can someone confirm that it could be the head gasket and not affect idle?