Running hot, now what?

My 96 Sport is running hot, and threatens to go to the red but cools down a hair with the fans and driving really fast. It still runs hot while I'm driving, but it doesn't threaten anymore. I attempted to flush it, but it didn't do anything except break something with my heater and now I have no heat.

When I had the hoses off to flush it out, there was rust lining the hoses, rust caked into the thermostat housing (new thermostat, a lot of good it's doing), and I took the reservoir off to wash and scrub the rust sludge out of the bottom. Do I need to just replace all of the hoses and take the radiator to a good shop and see if it's plugged up?

And most importantly, can someone point me in the right direction to get a better, more detailed manual? I've got a Haynes for Cherokee 84-2001 and it's only helpful for certain things, but mostly not.

Have you tried prestone's super radiator cleaner? If you have rust your radiator is probably clogged. I ran the super cleaner in mine for 5 days then the super flush and it seems to have cured my hot problem.

arsxj1 said:

Have you tried prestone's super radiator cleaner? If you have rust your radiator is probably clogged. I ran the super cleaner in mine for 5 days then the super flush and it seems to have cured my hot problem.

Click to expand...

Is that something I do myself or what? This is my first attempt at being mechanically inclined on such a bigger scale than replacing plugs and wires, can I google the information?

The heater core is also packed with crud. Take the hoses off before the heater core and flush back and forth until clean water comes out. You probably dislodged all sorts of debris with your first attempt. Now repeat .Do the same with the radiator also.Remove the bottom hose and top hose then flush back and forth.
Good Luck Ron

Be careful when/if you flush the heater core. Don't use too much pressure or you'll end up destroying the heater core (not a replacement you want to do) and have a nice puddle on the pass. floor.

You're lucky you are in SC as you don't really need antifreeze yet. I would keep changing out your system with water until you get it clear. Drain it, fill it up, drain it, fill it up. Let it cool down each time before your refill or you might crack something in the engine, like the head. If you did this daily for a couple of weeks, it should come clean. Then put in 50/50 antifreeze. You might also want to try a dose of brand name coolant system cleaner somewhere along the way, but I would do a couple of water flushes first to get rid of the worst of it.

If you decide to pull the radiator, keep in mind you can get a new one for $120 or so. If it needs repairs, you are best off getting a new one.

If it is not leaking, you don't need to do this yet, but if the rust is coming from there, it will happen soon. In fact, a lot of times flushing the system can 'create' radiator leaks, because a hole was either plugged by rust and then the rust is gone, or it had stop leak in it before that got washed away.

What you have in the hoses you have in the heater core, the block, and the radiator.

Get the commercial clean and flush stuff, Prestone is good, not the quickie crap, the kind you put in and run for 500 miles or so. Follow the directions. When done and ready to neutralize the cleaner follow the back and forth directions mentioned above for the heater core--start with flushing it backwards to kick out the big crap, use LOW pressure from a garden hose.

So while doing all of this radiator work and running it at idle for a while, I noticed something about the fans.

There's supposed to be two electric fans. One fan is missing and instead, there's a mechanical fan attached directly to one of the serpentine belt wheels and continually spins while the engine is running. The other is still attached to the original spot with no apparent damage, but only kicks on when the engine is a hair too close to the red.

I'm bringing it to a mechanic on base so I can use their lift for $3 an hour to replace the ball joints, and I'm going to ask about that, but what is YOUR opinion?

So, what made you think there was supposed to be two efans? No XJ left the plant with two efans, it was either one mechanical or a mechanical with an efan if a/c equipped.

If your mechanical fan's clutch has taken a dump then you will get temperature creep at idle and stop/go traffice, anytime the air flow through the radiator is reduced.

Warm the engine to normal operating temperature. Shut it off, then try and spin the fan by hand. It should not move very much. If it feels like it spins freely/very low resistance replace the clutch.

You can use the standard fan clutch, or if you want an upgrade you can purchase the ZJ HD fan clutch at NAPA, part number 272310, $44 and a direct fit. If you decide to go with the upgrade, don't let them palm off the ZJ MAX fan clutch, it won't fit in an XJ.

I thought there were two electrical fans because there's torn up plastic in front of the mechanical fan that looks a lot like the plastic housing for the electric. I guess it was just a guard or something. The mechanical fan does turn freely, so I've learned two things. And thanks for the advice on the upgraded clutch. I'll call NAPA and see what they say today.

If the mechanical fan shroud it busted/gone you should replace it, the shrouds helps air flow through the radiator and is an important part of the cooling system.

When I got my XJ I had that same problem......what happened is at some point you blew an upper radiator hose that whipped around and took out the plastic shroud for your mechanical fan. The stealership wants somewhere around $80 for a new shroud.....I found one online for $12 that had it at my doorstep 4 business days later. It installed in about 2 minutes time.