Sinking Creek 4WD Association

CHECK YOUR THERMOSTAT!!!

yes, i know its a new thermostat ... but i have had new thermostats that were bad out of the box ....

was the old one corroded? or was it gutted by the p.o.?

borrow a temp gun and check the rad for cold spots ... might be gummed up and not flowing water.

check oil for coolant, check coolant for oil.

are you burning a lot of oil / coolant? both of which could be head gasket. smoking at all?

The old stat was blown out. Who would have a temp gun??? The oil looked good and not really any smoke coming out of the exhaust.

old thermostat probably wasnt blown out. it was probably cut out due to a bad head gasket. here's an old trick that's always done me well. when you put in a new thermostat, drill a small hole (1/16" is a good size) right next to where the poppet is on the flat part of the body. place it back in the engine with the hole rotated to the highest point possible. a bad head gasket wont always spew oil into water or vice versa the way most believe. it can sometimes just leak compression into the coolant passages on startup and "lock" the thermostat closed. this allows the compression gasses to be vented into the radiator and out through the recovery system. I do this regardless to engine age and most import cars come with this from the factory because of the poor seal created by inferior gaskets used by manufactures in the 80's that were not able to cope with the different expansion times of aluminum and iron. the jeep has a iron head, but you get the picture. also, just run a hose between the two engine ports for the heater to see if that's the problem.

Are you sure you are over heating? Before you go ripping into it you might want to stick a cooking thermometer in the rad to double check the temp gauge on your dash. Obviously disregard this if you got to the point where coolant is boiling over and what not.

Maybe it’s just a Toyota thing but I know the factory gauges on my truck act more like an idiot light if anything. Ask Ary he knows all about shitty factory gages.

MtnToys wrote:Are you sure you are over heating? Before you go ripping into it you might want to stick a cooking thermometer in the rad to double check the temp gauge on your dash. Obviously disregard this if you got to the point where coolant is boiling over and what not.

Maybe it’s just a Toyota thing but I know the factory gauges on my truck act more like an idiot light if anything. Ask Ary he knows all about shitty factory gages.

no the first time it over heated (when the upper hose blew) it was definitely boiling.

And Terry I'm fairly sure the thermostat was gutted, it looked like somebody cut the two arms on it with tin snips or something (very clean cut). I forgot about the drilling the hole trick....but we were at bobcat anyways, no drill to be found.

His coolant looked normal not nasty, and his radiator doesn't looks old or corroded in any way, although that doesn't mean its not gummed up somewhere.

I won't be back from TX until late Sunday night, but I have a temp gun and a head gasket leak detector (detects the level of exhaust, if any, in the coolant) if you don't resolve the issue before then.

That would be great if I could borrow them. I'm going to drill out the stat and maybe get another one if that does not work. I'll let you know Monday if I still need to borrow the gun.
Thanks

The Jeep sputtered for a while then it came to life and the temp. dropped dramatically. It did eventually go back up though. I'm assuming there is a ton of gunk throughout the system. Should I flush out the whole cooling system? Or now that the gunk blew thru should I try another stat? I'd like to resolve this soon cause I want to get some more mud on it. I'm amazed I have not had a 4x4 in so many years. I forgot how much fun they are.

the mud always comes back to bite u in the ass

Put a new fan on and now it doesn't overheat, however I think I killed the motor. It now runs like crap and is bleeding oil out of the oil pan. The lifters are knocking very loudly, I think it is done. I have wanted a fuel injected motor and have found an 87 cherokee with a fuel injected 4.0 Its an automatic 4 door that runs well. All I want is the motor. Remember I am no mechanic so I'm looking for someone willing to switch out the motors for the remaining cherokee with all it's parts, my old motor, and cash. If there is anyone wanting parts and money for the work please let me know. I would rather give the money to one of you guys than a garage.