Chasitek

This is my first time posting so go easy on me. I know there are a million forums about cherokee overheating but I couldn't find one that matched perfectly with my issues. So I have a 1986 jeep comanche with a 96 cherokee 4.0 HO in it. One day there was a weird noise coming from under the hood and I couldn't pin point it so I brought it in to pep boys. Worst decision ever made. They screwed up my electric fans and the latch on my hood so I ended up having to buy new fans and a new latch and redo the whole upper radiator support. Finally finished it. Took it for a drive and the gauge said it was overheating. I do believe it was overheating before I took it it and everything but can't remember. Anyway, I replaced the thermostat and it stopped for a day. Then the next day it started again. I flushed the cooling system. Still overheats. Replaced the coolant sensor. Still overheated. Finally replaced the water pump and is still overheating. The day after I replaced it there was a leak of coolant where the waterpump is but it didn't look like it was the waterpump. I cleaned it all up and the leak stopped. I know it wasnt left over coolant from changing the pump. It was a fresh leak. Ever since, I haven't seen any leaks but it still overheats. All that's left to possibly change is the radiator itself and the head gasket. I will mention that the e fans I have set up right now are pushing air into the rad not pulling. It was all I could do at the moment. The fans didn't clear and would hit the pulleys as pull fans. I know it's not ideal but could that be the problem? I checked all the hoses. No leaks. I had the heat running on max and it would keep the needle slightly lower than with it off. Then the other day the blower motor or something went out so the needle went back up. The needle lays right before the red zone and today went just barely into the red zone which it has never done before. It's not hot outside at all. It's about 65 farenheit outside. I've burped the system however had to add more coolant before I did since it wasnt full in the rad which was weird since the reservoir was full and hadn't gone down since I had last filled it. i am officially out of ideas. There's no coolant in the oil or vice versa. When I start the car no coolant shoots out the cap. So I don't think it's the head gasket but I know the only way to find out is to do a cylinder test. Last night I checked all the fuses and relays, all seemed good. After I drive it if I pop the hood, the engine itself feels pretty hot but the radiator seems fairly cool. I can put my hand on it and not burn it or come anywhere close to burning it. The thermostat hoses feel really hot, too hot to touch for more than a second. Any ideas would be GREATLY appreciated? Thanks!

tech

How old is the thermostat and the radiator ? what kind fans do you have .

Chasitek

The thermostat is a month or so old. I've taken it out at least 3 tumes since I got it. I dont know if that matters. I have no clue how old the radiator is. Looks newer but some of the fins are bent

Chasitek

Oh and as for the fans. They were hayden automotive 3680 rapid cool thin line electric fans off amazon. They had bad reviews but all the reviews were about size or mounting them with zip ties so I figured i'd give it a shot.

elwoodblues

When does it over heat? At idle, running or both?
Couple things I'd look at:
1. Take the tstat out and put it in boiling water, should open around 195.
2. Is the AC condensor damaged/clogged? It's already blocking the rad so if it's clogged that doesn't bode well for the radiator

SirCyber

Please do all the steps in this video. Sometimes it's easy to miss something and the jeep in this video is TERRIBLE, so he does an extremely thorough cleaning and flush.

bigvig

First thing that came to mind is you have an air pocket. Ive seen this exact problem before, and it was due to not burping the system correctly. Have you burped the system correctly and filled it until there was no air bubbles left? It can take literally HOURS to do it.

craigjacob1

If the fans are flipped (as opposed to being placed on the other side of the radiator) that is a bit of a problem. They will only help when you are at a standstill, and even then you will be using hot air from the motor to cool the radiator. When you are moving it will be worse than not using fans at all. The electric fan motors are also not intended to handle that kind of stress.


Check that your lower radiator hose has a coil spring running through it. That spring keeps the lower radiator hose from collapsing and blocking coolant flow after the engine is warm.

freegdr

Will factory fan setup not fit ? Electric fans will never cool as good as them.

TimV

T-stat in backwards....?

Bugout4x4

This is more common than one would think!

Chasitek

I'll check the backwards t stat. I don't think it is. I burped the system correctly as far as I know how. I put the truck on a curb to get a slight slant uphill and turned the car on and poured coolant until it wouldn't go down anymore. I'll check it again today to
make sure it's still up to the top. Now for the fans. It was kind of rigged to fit. The e fans don't really fit behind the radiator as pull fans since there isn't enough clearance. I can try and make it fit. It only doesn't clear by 1/4-1/2 an inch, my only fear is if it vibrates. The fans will hit the pulleys and mess it all up. I believe the spring is in the lower hose. I felt it. Couldn't quite tell so I had my girlfriend start it up and rev it and it didn't collapse from doing that so I assume there's one in there. I've completely flushed the coolant. That was the first thing I did. It's greener than green. Not a slight hint of brown or anything. I've flushed it at least 4 times since Removing the water pump and everything flushes most of it anyway. He first 2 flushes were through the petcock on the rad. No water has touched the system. I buy 50/50 mix and have never flushed my system with water or put water in it on the side of the road so shouldn't have any rust. Any only suggestions if the t stat isn't the problem. I'm thinking the fans could be the problem. Once the engine's heated up. The air the fans blow is fairly warm when I out my hand behind the rad. However I really think it's just the heat coming off the engine.

Bugout4x4

The spring side of the stat goes into the head. And while you have it out I would drill a small hole right at the top below where it lands in there and above the little hole already in it. Then make sure these are clocked in the top position. The extra hole really does make a huge difference in getting all the air out. This first became a mod back when Ford started putting out V-6's. There was absolutely no way to get all the air out of those unless you did. And I once had to buy three brand new T-stats before I finally ended up with one that would work correctly as it should.

SirCyber

Just a mention... Burping in my mind involves massaging the top radiator hose to force out the air bubbles. Squeeze it to collapse, release. Repeat as often as necessary.
If you put water into the radiator, or coolant, and only opened the petcock, you may be bypassing some serious or complete blockages. X2 on the fans... They should be pull, not push.
Straight water in the coolant system will not hurt at all. You are performing a flush, not using water as coolant.

Chasitek

I'm going to test the t stat first and then move on from there. I really don't think I put it in backwards. I'd have to have been reallyyyy tired and not paying attention or something since I know how they're supposed to go in but I did kind of put it in quickly so it's a possibility. Lol. I'd like to buy a t stat that opens at 180 instead of 195. I have a 97 wrangler too I'm pretty sure it had a breather hole so i'm probably gonna get one for a wrangler and put it in. Though I never knew the breather hole served such a big purpose. I guess every little bit can count in a cherokee��