Almost have given up on the ol Wrangler

[superj]

After all the time spent swapping the motor and getting different things and wiring and shifters and everything, it has a slow overheat that I cannot beat.

It didn't have a thermostat so I put one in. Still doing it. Bought a new hd three core radiator, still overheats. Put all new hoses in case they were sucking down but no, still overheats. Flushed and flushed and flushed some more, still overheats. Checked water pump to make sure its good, it pushes water and works great but jeep still overheats. Bought twin electric fans and out one where the inlet hose is and the other where the outlet hose is. Wired them on their own relays for max power, still a slow over heat.

I don't know what to do now, I have tried everything. Jeep runs great and is a blast drive but I only get about 10 minutes out of her till she is sitting in the red and then shuts off if I don't shut her down.

Any ideas?

 

[cougarlasch]

Do you have a fan shroud on it. And is the temp shown on the guage the actual temp of the engine. Maybe showing a false temp. Hope ya find out what's wrong

 

[JPNinPA]

I have a bunch of questions:

1.) what temp thermostat and what brand / model?

2.) What pressure # or lb radiator cap?

3.) describe overheating. Just the needle going into the red? Boil over into the reservoir? Only while driving or while idling or both? Over 35 mph or under 15 only or both?

4.) what is in or in front of your grill.

5.) does the radiator fit tight to the grill and are the rubber gaskets and flaps on the sides installed?

6.) do you have a clutch fan? Stock and is is always engaged?

7.) do you burp it after cool and refilling?

8.) do you have an overflow and does it or the hose to it leak?

9.)

 

[superj]

1: I don't remember the temp I got. Oreilly's had a few to choose from but I don't remember which one I got.

2: 16 pound cap

3: needle goes in the red and jeep losses power and then shuts off. Does it on highway or idling.

4: nothing in front of grill

5: I am not sure how much room is around the edges of the radiator. There were no types of rubber or little gaskets sealing the old one so I didn't have anything to out back with this new one

6: I just took the stock fan, clutch, and shroud off to put these two electric fans on today

7: yes, I burp it. The 302 is a lot easier to fill then the i6 was

8: I do have the stock jeep over flow and it doesn't leak.


I don't have anyway to tell I'd the gauge is reading improperly. I have been hoping that is the trouble but since the jeep losses power and shuts off, I think it's right. I used the stock sending unit when I swapped motors so my gauge would read properly and it was as correct as stock can be before so I don't think it's worse than before.

I know the fans move a ton of air through the radiator now, and I mean a bunch. I had the jeep idling in the yard under the tree and when leaves would fall in front of the grill, the fans pulled them over and stuck them to the leading edge of the radiator.

 

[Gennybro]

Possibly a bad sensor telling the jeep to shut down. Does it actually boil over ? I feel that electrical issues should be looked at, just a thought.

 

[JPNinPA]

1: I don't remember the temp I got. Oreilly's had a few to choose from but I don't remember which one I got. 2: 16 pound cap 3: needle goes in the red and jeep losses power and then shuts off. Does it on highway or idling. 4: nothing in front of grill 5: I am not sure how much room is around the edges of the radiator. There were no types of rubber or little gaskets sealing the old one so I didn't have anything to out back with this new one 6: I just took the stock fan, clutch, and shroud off to put these two electric fans on today 7: yes, I burp it. The 302 is a lot easier to fill then the i6 was 8: I do have the stock jeep over flow and it doesn't leak. I don't have anyway to tell I'd the gauge is reading improperly. I have been hoping that is the trouble but since the jeep losses power and shuts off, I think it's right. I used the stock sending unit when I swapped motors so my gauge would read properly and it was as correct as stock can be before so I don't think it's worse than before. I know the fans move a ton of air through the radiator now, and I mean a bunch. I had the jeep idling in the yard under the tree and when leaves would fall in front of the grill, the fans pulled them over and stuck them to the leading edge of the radiator.

Yes check the sending unit. You could measure the resistance as the temp rises. I hope you didn't use anything or did use conductive anti seize as the threads of the sending unit are the ground path. I'll post resistance numbers if I could dig them up.


No fluid is lost and it doesn't boil over correct?

Has it done this since the install?

 

[superj]

No fluid loss or boil over, just loses power and shuts off.

I guess I will pull the unit and clean the threads since I did use Teflon. I figured the threads would cut a groove and make contact but I will give her a try

 

[Gennybro]

And you thought you was almost done.

 

[superj]

I know.

I am almost done, but not in a good way. I have thought of selling and just getting something else and I have though of just pushing it in the garage and leaving it till next summer

 

[Gennybro]

Oh man,:shock: you can't push it into a garage and leave me in suspense all winter to see if I'm right. That just aint right.

 

[superj]

i haven't messed with it since the weekend. took my son to take his driving test and have been working on getting his cherokee up to passing the state inspection. two things left and then the wrangler will be the only thing to work on.

 

[Gennybro]

Ok cool, cause I really want to know what the problem is cause it's just plain wierd. Well electricity does wierd things.

 

[cougarlasch]

you say it loses power and just shuts off. does it have a catalytic converter that is maybe plugged up?

 

[Gennybro]

Good point .:yeah-that:

 

[superj]

it does but doesn;t seem to be clogged and it doesn;t heat up but i will check it out. i hadn't thought about that but we shall see when i get back on the ol jeep. i did the temp sender yesterday but hadn;t dropped a battery in place to see if that helped or not.

i wonder, i had to use a bushing to step the intake hole to the size of the sender. do you think that is going to mess up the readings since its a brass bushing? the resistance will be different using brass versus using steel? i am trying to find another hole to put this aftermarket temp sensor in that is the proper size and see how they read against each other

 

[JPNinPA]

No the temp is taken from the tip not the threads. Even if it did, at worst, it would read cooler not hotter. The PCM is receiving a high temp signal, causing your issue. Any intake or exhaust leak?

 

[superj]

no, everything is good.

the pcm sends the reading to the gauge? i know there is a circuit board but i didn;t know that stuff went through the pcm since its an older yj.

 

[JPNinPA]

No sensor to PCM. Older jeeps had two, one for gage and one for PCM.

Remind me what year and engine was this jeep origionaly?

 

[Gennybro]

Now this is geting down right interesting.

 

[JPNinPA]

This is what a temp sending unit looks like for an 87 YJ. It has one pin so Teflon will likely cause an issue. Have you checked the gage cluster connector for rust or oxidation.

The other question I would have if you actually overheated would be if the water pump was pumping in the correct direction.?