cherokee-90

I was driving down the highway yesterday and I could smell something burning, turns out it was my engine, The temp gauge didnt read it was overheating but clearly it was. I ended up pulling over when I realized the jeep had hardly any power and I was hearing a ticking sound that got quite loud. There was coolant leaking everywhere under the jeep. So i got it towed to my parents house and looked at it. Turns out a frost plug had a small hole due to corrosion so all the water in the block had drained out. I put a rubber replacement frost plug in it and topped up the coolant. So now it runs cool and all that is ok, but the jeep runs very rough, especially at low idle and it backfires when accelerating at low rpms and pulsating when not under much loud. It also barely idles. It isnt blowing any smoke and there is no water in the oil. Tommorow I'm gonna do a compression test and see how that is. Any ideas on what may be broken??? it runs strong at the higher rpms just not good at low rpms.

any help is greatly appreciated!

flav

Sounds like the engine is shot. The lack of power is most likely from a crack in the block somewhere from when it over heated...

Jeepnick

When coolant is very low the highest and hottest part of the motor is at risk from heat damage. This is the cylinder head. More than likely it is cracked, normally between two valves. This small type crack will prevent the cylinder from fireing properly, hence the rough running. The proper repair is a new or reconditioned head.

jeep_josh

hi, new guy here but long time jeep owner. had similar overheating problem about a month ago and after fixing main problem also had poor running problems. no water in oil or any leaks i could find, turned out temp sending unit was out of range and causing it to run overly rich. has been running great since and not smoking or dripping anything. hope yours is this simple too.

Johnny9Inches

Is your coolant disappearing but not showing up in your oil? Mine was small crack it was burning off before it got to serious, also check your head gasket, dry head at high temp tend to cook these.

Does your exhaust smell sweet?
Pull your plugs, are they really clean?

If yes to either of these its either the head or head gasket, you can see it in the head by pulling the valve cover, chocolate milk color under there at all SWAP IT

Head gasket, is a bear to get to, but a good learning experience. If you have to swap the head, PM me I can help you threw some of it (as i just did mine)

cherokee-90

Well I got lucky. The spark plugs got very very hot and were in terrible shape... I changed them out along with a new cap and rotor. Jeep runs like a top again!!

also I we did a compression test and all cylinders were 150, except the number 3 cylinder was 140. but that is really good.

phewww!

Thanks for the replies,