`89 Cherokee Limited 3" ProComp lift 31" BFG TA/KO
 ??? BLOWN MOTOR ???  
I started my cherokee in the garage tonight to warm it up before going to the store. I kinda got sidetracked and it ran for about 45 min. When I went back out to leave it had puked its coolant out and was smoking pretty badly but still running. Have no idea why the cooling system blew yet or how long it ran like that. Let it cool down for an hour or so and when I cranked the motor I was getting some pretty bad knocking. It seemed like it wanted to run but I didn't let it start. I'm gonna check it out a little closer tomorrow. I was just wondering if anyone else has had this or anything similar happen ???  

before you get too worried, check all of your hoses and radiator. i had a heater hose fail on me a couple summers ago and didn't notice until i stopped. i don't know how long i was running like that, but i haven't had any issues with the engine. check the oil as well, to make sure there's no coolant in there (it will appear milky)  

One question, was the temp gague pegged?  Too bad cars don't have a high temp shutdown huh?
Anyway, like previously mentioned, check the oil to see if its milky (coolant mixed in).  Since very high temps degrade oil, I would change it before starting it.  If you don't get to it for a while, keep a close eye on the oil when you first pull the plug because if there is any coolant, it will be on the bottom of the pan.  Also check for metal, this would be a huge sign if it's toast.  You might want to check the oil filter for metal debris as well, it only takes a minute.
If you have a compression gague, you can check for a bad piston or scored bore.
As for the smoke, was it in the exhaust and did it smell like oil or coolant?
If it was real bad, you may be able to tell what cylinder is bad by the spark plugs.
Thats all I can think of at the moment.
Hope it ok and good luck!!!!!!!!!!!!  

That is a great idea, a high temp shut down!!!  

Actually, all you would need is a temp gague with an adjustable needle set to the desired temp.  On the generators I work on they're called a switchgague and they are made by Murphy.  Just wire it inline with the electric fuel pump to a normally closed contact on a relay.  Wire the coil to the postitve of you battery (fused of course!!) and when the needle grounds out, the relay activates, opening the contact and shutting off the fuel!!!  

perfect  

Could it have overheated due to the fact that it was in the garage? Too close to the wall it would seem like it could get hot where it wouldn't have outside!? No air flow no cooling!

Just a thought!

-Cliff  

the clutch fan was probably bad or weak. you generally don't know you have a problem there untill a nice hot day sitting in traffic,

a temp sender switch could be used as a high temp shut down as the same type of sender is used to turn on electric fans.