chefeagles

1991 cherokee briarwood 161k 4.0.

about 3 weeks ago jeep was idling in park and i noticed a little white smoke coming from exhaust gave it some gas and some more smoke came out. then it didn’t do it again until a week ago it was a hot humid night just started it up and gave it some gas and out came a cloud of white came out. oh boy. but then it stopped and no smoke. then today it was pretty warm out had the ac on going uphill on the high way i pretty much floored to get up the hill faster looked out my rearview and white smoked engulfed the cars behind me. and then after that id floor it and nothing no smoke. then tonight heading home i stopped for a min and idling it started getting hot past 210 but then once i got going again it was normal like 190. did i blow a head gasket and my jeep is just hanging in there for now?

mike37

sounds like a head gasket
any good radiator shop can easily test to see if you have any combustion gases in the coolant

a head gasket is a easy fix if you have any skills

BuckB91XJ

Chefeagles, sounds like you may have a blown head gasket. The white smoke you're seeing is excess water being burned in the cylinders. Check for oil in the coolant and coolant in the oil. You can also do a compression and leakdown test on your cylinders and your cooling system. The overheating pretty much settles it that is what I think you have. Stop driving it and get the head gasket swapped out before you damage the head or even the whole motor.

BuckB91XJ

You beat me to it, Mike...lol

mike37

that amassing cus usually a 5 year old can type faster than me
and spell better to

BuckB91XJ

I'm as computer illiterate as they come.

chefeagles

well i got no water in the oil and no oil in the water. i will pull plugs and test compression.
today tho i drove to work and back no smoke at all. the oil pressure was at like 70 psi first 10 mins of driving and then went down to about 40-45 psi doin 65-70 mph but when i would have to stop temp would go about 210 and oil pressure would go below 20. and when i got moving again things would go back to normal.

mike37

it wont alway show up in the oil
could be blown between the cylinder and water jacket

BuckB91XJ

The white smoke out the tailpipe and overheating definitely tells me that you have water going from the cooling system into at least one of your cylinders. Bad news. Bad head gasket.

chefeagles

well just did a compression test all cylinders check out fine. first crank or two i get 90 psi then six or seven cranks i get about 155 psi. so does that rule out head gasket???

sluggy

might be a cracked head?? sounds exactly like a old bmw i used to have, till it overheated and siezed
compression on that was fine, but as it got hot the crack would open?
yea i thought it would have closed to.

chefeagles

how do i find if the heads cracked?

sluggy

rip it off and take it to a engine refinisher unfortunatly.

mike37

take it to a radiator shop they can do a quick test to see if you have
combustion gasses in the water its easy and should be cheep

that will tell you if you have a crack or blown gasket

chefeagles

ok so here is the latest.
its been about a week since the giant cloud of smoke. I had the combustion gas in the coolant test done and big negative no gases in coolant.
so i guess no bad head gasket no cracked head.
Thing is the jeep hasn’t smoked even a little bit all week but all week long when im idling in park natural or stopped at a red light the engine kinda surges( I dont know any other word to describe it) looking at the engine it will randomly kinda shake once or twice outa rhythm with the normal engine shake and also the same sorta thing happens with the exhaust. theres the normal constant air flow with a random burst or two of exhaust.
any more help would be much appreciated.