mikexj

I am looking for some advice on my 94 xj 5-speed, it is running hot on the highway and when pushing it hard on the trail, thermostat seems fine, not looseing any coolant, water pump is not leaking, flushed the rad and seems it has helped a little, rad is in decent shape, head gasket is not blown (no milky oil and not white smoke)I have noticed that one of the freeze plugs (front of the block) is leaking when the engine get's real hot. Could it be that because the freeze plug is weeping that the system is loosing pressure and therfore not working properly. One mecahnic has checked the thermostat and said it is in working oreder the other said how could he tell, let's change the thermostat and go from there. Any comments advice for me. XJ is running 33's on a 4.5 lift 280 000km on motor does not burn oil and had tune up done last week.

Mr White

iTrader: (1)

A shot in the dark: Do you have the a/c rad sitting directly in from of the engine rad. (like grill rad rad fan engine) as the first rad might have mud or bug fluff stuck in the grill and the air is not getting though like it was all clean. I had this problem and since my a/c wasn't working I completely remove the a/c rad which made a hugh difference in summer. To clean it try taking a hose (not to strong pressure) from the fan thur to the front this might push whatever crap is stuck there.
You have 2 fans one runs all the time and the other is electrical runs when it get over a certain temperature (are both working properly)

mikexj

I do not have a\c in the truck so I don't have the second fan, I was told that I should find one at the scrap yard and install and that should help (thoughts), sort of at a loss of explanation as to what is going on, it is at a shop right now I am haveing the thermostat changed and a new freeze plug in to replace the leaking one. Iwill see what happens on my drive home and let you know.

Mr White

iTrader: (1)

Lets eliminate things: Anti-freeze is okay at the proper height in rad. (If its below the proper level it will run hot,Also is the reservoir. Where the fan is the "Radiator fan SHROUD" is still there, as if it isn't this will make it run hot as the fan isn't able to do its job properly you will be loosing to much of the cooling air out the sides. Ck water pump (if u need to know how to do this I'll tell you) Also a friend might have one of those meters to check the codes there should be some if your running hot. The above on the weep/vent holes leaking after you get it done lets know.

mikexj

good piece of advice on the shroud never even though of that nor did the mechanic (i suppose), just had a look all is good, had the thermostat changed today no luck still running hot, ordered a new 2 core rad for it today, saw that a 3 core would not fit properly (fan etc) decided that if amc designed it with a 2 core should be good enough, it is going in on friday and the freeze plug will be changed at the same time. we will see how that works out if you don't mind advice on how to check water pump would be apprecited, had a look is is not weeping any coolant.

Mr White

iTrader: (1)

A quick test is to pinch the top rad hose closed with yur hand while the engine is idling (keep ur hand away from the fan) then release it. You shud feel a surge of coolant if the pump is working properly.

mikexj

had the rad changed today, it runs great now, no more running hot, it was cold out but believe my problems are over for now!

Mr White

iTrader: (1)

Great NEWS. Sometimes problems people have are hard to pin point from a desk miles away, helps to be able see what the problem is and sometimes 2 or more heads are better than one.

8e9heep

My 89 Cherokee used to run hot all the time and blow up the coolant reservoir evey now and then. One day it gradually stopped blowing hot air out of the heater, it was winter, until it just blew out cold air. I ended up getting the heater core back flushed and guess what? The first thing I noticed as I drove home was temperature gauge was lower and never went as high as it did before. It used to run very close to 100C or 212F, yes the boiling point. Now it runs where one would expect to be as far as temp is concerned. I have not had to replace the reservoir or add coolant like before.