Definitely a concern on cooling. Also when you have the belt off, look at the main pully( called a harmonic balancer). It's two pieces glued together so if it's beginning to fail it might cause a belt to slip. If it wobbles at all, change it, same for the AC pulley. I would get a new belt( Goodyear or gates) and check all the pulleys. The vendor section has a couple of threads with good hood vents, about 275 for a nice set. The rockstar blocks were only 20 bucks, if they don't work I'll try louvers myself. Oh yeah, the fan clutch only installs one way, it's marked front and back on most.

Don't forget to check the tension first, that might solve the problem.

 

Too be honest, youll be surprised how many people are *******s even after helpful advice is given. I apologize. And I see I came back late and that some good info was given. Hood louvers dont do anything for engine temp, just underhood temp. Def back flush the heater core. Was the T stat a motorad?? And also the radiator cap, how old is that.

 

You hit the nail on the head. This new guy is a-okay in my book. As are you!

 

This is the thermostat I bought


Today is first day we got up to 85+ here in North Carolina, I'm near Winston Salem and I was running at about 220 I had to turn heat full blast and watch it like a hawk.... after a while it got down to 215 and I was ok, but I was burning up the whole ride home, it seems my heat only works when the engine is 215 plus I still need to do that heater core flush, I will do it tomorrow along with a double check on the t stat! Has anyone heard of water wetter is it any good ? Should I try it ? Also I'm not sure if my radiator is the double fun or single fin.... I took it to a 4x4 shop and they said it was a stock Cherokee radiator but I've heard some are double fins, some are single, but who knows if they really even put the stock Cherokee radiator in I'll post up some pictures tomorrow to see if you guys can tell. Oh and sycoglith it's all good glad we are on the same page thanks for the help man!

 

On a properly functioning cooling system, you shouldn't even need the heater core. A number of guys have just bypassed them altogether and not had any overheating issues. I have a stock system, although everything was replaced 3 years ago with new parts. I live in Texas. I can crawl along in rush hour traffic in 100 degree heat, on pavement that measures at 160, with the AC and an never get above 210. I have a 2" lift, stock 3.55 gears, a roof rack, a JCR winch bumper with a bull bar, and an 18" LED light bar mounted to the bull bar all blocking airflow to the radiator and I still don't have issues.

Although, if you do flush it, look on youtube for a video by Eric the Car Guy. he does a core flush on a Grand Cherokee, and shows you step by step, although it's not rocket science.

I went back and checked, and just to clarify...
Did you put a new radiator in? Or did you just put in a used but "new to you" radiator and flush it. The reason I ask is that radiator flushing is not an exact science or guarantee that it's not still full of flow blocking deposits and gunk.

Have you "burped" your system? The 4.0's are bad about having persistent pockets of air trapped in the block. There are many methods listed for dealing with this. All I did was take the radiator hose off of the thermostat housing, and start filling the non-running engine with coolant. Once it started trickling out the top of the the housing hose flange, I hooked everything back up and tightened it all down. Then started the engine to get the pump going. While this was going I kept putting coolant (pre-mixed) in the radiator fill neck till it wouldn't take anymore. Then I put the cap on, filled the overflow reservoir, and drove it for about an 8 mile trip around town. I stopped once halfway at a car wash and saw the overflow reservoir was dry, so I added more coolant to it. Then drove the rest of the trip and checked the reservoir again and filled it to the proper mark. It's never run hot on me.

A couple of things that haven't been mentioned definitively:

What lift and tire size or you running?

What gearing? Stock? 3.55?

If anything, how much stuff do you have mounted in front of the grill? Lights? Winch?

Have you checked the fan clutch? At full hot with the engine running, have someone shut it off while you watch the fan clutch. If it free-spins more than a couple of turns after the engine stops rotating, you probably need to replace it.

Have you checked to make sure you don't have any brakes binding?

If an automatic, what does your trans fluid look like? If it's dark and smells like death, try doing a "forward flush". A trans running hot sends its hot fluid to the radiator, and could contribute to your overheating problem.

Here's a link to where someone quoted my post on how to do a forward flush. It's faster and way easier than dropping the pan half a dozen times and changing it 2 or 3 quarts at a time. It also has the advantage of allowing the new fluid to flow through your torque converter and giving you some confidence that all of the fluid actually got changed. And in a way that won't potentially damage your trans like the typical "reverse flush" that many shops do.

https://www.cherokeeforum.com/f2/tra...4/#post2566375
The last thing I can think to check is that the thermostat isn't sitting in the housing crooked. It's been known to happen. I had it happen once to me, and my brother just bought a 2000 a couple months back, and his was in there sideways.

If you get through all of this and the items others have mentioned and you are still overheating...

Hell... I don't know.

 

It's a 1999 on a 4.5 inch rc lift but it's really about 5.5 inches....
It's stock gearing with the 29 spline Chrysler 8.25, I have 32x11.5 mud tires. The radiator I think was used but new to me I'm gonna post pictures of it later so hopefully someone can tell me if it's double or single fin. I've checked the t stat, it's in there right and I boiled it and it opened at 193..... I will do that flush and check the tranny fluid today, what color should it be? How should it smell??? I do have a light bar in the front but it's a 10 inch and blocking very minmum of the radiator, I was having the overheating issue before I installed the light bar so I doubt that's it.... Thanks everybody I'll do the flush and check the fluid and post a few pics later on today hopefully!!!

 

A new radiator is a hundred bucks. I would always do new on that type of part. Who knows what's in that old one even if it looks ok, you can't see inside build up that may reduce efficiency. You've got some real expensive accessories and add ons, give the old girl a new radiator.

 

Agree on the always new. Hell, i got mines from advance and used coupon codes. As for burping, when i just re did my cooling, i filled some coolant into radiator fill hole. Turned jeep on and kept filling and watching it bubble and spit out coolant so in goes more. Eventually it all comes out. Plus with our open system, with the proper cap, it burps itself of the last in time. When burping, since you have a 99, no need to run the heat as coolant is always circulating. Also, i forgot, what kind of coolant did you use. I went with peak green concentrate and mixed my own with distilled water. I did 50/50 but if your at an area that doesn't see freezing you can do 75 water and 35% coolant iirc since the coolant does more for freezing

 

Alright so I did the flush and a double Check on t stat I've already done a burp so here's some pics....


That's my light bar not blocking much.


Can you tell if it's double or single fin by this pic??? sorry it's crappy, I got home late and by the time I did everything it was dark.... from looking at it it really looks like there's a radiator then another one a little smaller in front of the radiator.

 

That light bar aint nothing. I have one like it and i have no issue. Check the questions i asked in my post. Oh and that smaller radiator looking thing is the AC condensor. Looks like a stock setup

 

I used peak green 50/50, and I have burped the system so I'm 99 percent sure there's no air....
Does anyone know if water wetter is any good or worth a shot ?

 

What about the radiator cap. And when you wheel. What gear you in etc. i forgot did you say your tire size

 

Yeah, that light bar isn't even a blip on the radar.

Per your earlier question...

The trans fluid should be pink/red and translucent. If it's pink or red but cloudy/opaque, or if it's brown/black, you need to change it. The trans fluid actually gets very hot. It is sent to a closed tank inside the driver's side of the engine radiator to be cooled. If circulating it through 210 degree water cools it, that should give you some idea how hot the trans fluid can get.

While your tire size is definitely out of what would be considered the acceptable range for your stock 3.55 gears, it's hard to say how much that may be contributing to your trans temps, and thus your cooling problems. By most measures, 31's are about as much tire as you'd want to run on 3.55's. I will be running 31's after my lift, and already have the 4.10 gears waiting to go in. Were it me, I'd be running at least 4.10 for 32's, if not 4.56 gears.

To sum up, you know how much a new motor costs. Do yourself a favor and pick up about four gallons of Dex/Merc III from Wally World for $50 and flush your trans per my link, and buy a new $100 radiator and swap it out.

The trans flush is just good maintenance on a 15 year old rig whether you had cooling issues or not, and could save your trans, especially since you're working it pretty hard with big tires and stock gears. Put the radiator in as cheap insurance against replacing another motor. This could also help keep your trans temps down.

I mentioned my situation and no overheating issues. Compared to what I have, your light is nothing.



Bi Xenon 004

 

I wheel in 3rd, and my trans fluid is dark brown guessing this isn't good!!!!! I'll have to change it how do I do that? I'm not exactly sure....

 

Just look back at the earlier macguyver post. He put a link to a thread describing the flush process for the tranny.