4.0 Engine Overheating

[JMT]

What housing is leaking? Thermostat housing or water pump housing behind the main pulley via its weep hole?

Thermostat housing. Just under the lower 13mm bolt that holds the housing to the block

 

[Jerry Bransford]

Not necessarily, mine did the same thing last week with the heat wave. 3k rpm for 45 minutes on the highway in 115* and I was creeping up around 225-230.

Refer to what I underlined in his post that I was saying was not normal.

 

[Trevlaw]

Refer to what I underlined in his post that I was saying was not normal.

Ahh gotcha, missed that

 

[JMT]

What Fan Clutch? I'm having a hard time finding a Mopar.

 

[TheBoogieman]

What Fan Clutch? I'm having a hard time finding a Mopar.

I've used Hayden with no issues.

 

[JKP]

Yeah, Hayden/Imperial seems to be about it.

 

[Jerry Bransford]

Yeah, Hayden/Imperial seems to be about it.

Hayden worked well for me.

 

[JMT]

Parts are now on order. I'd like to really get this done soon so the boys can show their Papa their new Jeep and take him for a ride in it. Now that we live in the PNW, the boys only see their Papa once a year and Papa is getting up there, 75. They're coming Tuesday of next week.

 

[Jezza]

I replaced the thermostat with a Stant 195

Stant is not one that I would consider trustworthy

 

[Mike_H]

@Jerry Bransford @Mike_H . I removed the thermostat housing and the thermostat did not have the fitting allowing air to pass, so I drilled a 1/8” one near the lip and re-installed it at the top. Re-installed The housing and remove the radiator cap to allow it to burp. I squeezed the upper tube to help move air out. I also added some 50-50 G05 coolant to the radiator (at the cap) and started the engine. It ran for a while heating up slowly and the fan seemed to keep the same speed the entire time. I could not see fluid moving through the radiator. When it got to 210 it kept heating up to my great dismay. I also noticed that the housing is still not sealed and coolant was leaking very slowly but it seemed like it was dripping in a steady pattern. I don’t know if that could indicate the pump is working or not. The bigger radiator hose was really hot. Thoughts?

Well, if the upper hose got hot, that means the thermostat opened. If you can't see the coolant moving around in the radiator, you have it right, ordering a new water pump.

It's been a while since I've pulled the thermostat housing... Do one of the bolts go into the water jacket? You might need some sealant on the threads. Also, buy another thermostat housing gasket and some permatex aviation form-a-gasket. I use that stuff on my water pump and thermostat housing. Helps the gaskets seal tight... Put it on both sides, wear gloves.

https://www.napaonline.com/en/p/PTX7651210

 

[JMT]

Well, if the upper hose got hot, that means the thermostat opened. If you can't see the coolant moving around in the radiator, you have it right, ordering a new water pump.

It's been a while since I've pulled the thermostat housing... Do one of the bolts go into the water jacket? You might need some sealant on the threads. Also, buy another thermostat housing gasket and some permatex aviation form-a-gasket. I use that stuff on my water pump and thermostat housing. Helps the gaskets seal tight... Put it on both sides, wear gloves.

https://www.napaonline.com/en/p/PTX7651210
View attachment 262895

Great help. I feel like I’m so behind the curve on all Jeep things. I’m always in the learning curve. Hopefully my boys will at least start ahead of me. Thank you

 

[Trevlaw]

Ok, just to double check. I drove to work this morning, about 15 minutes at 65mph. Parked, popped the hood and I could spin my fan with one finger very easily. That means the clutch is bad right?

 

[zebra12]

A Lisle funnel makes burping the system really easy.

 

[JMT]

About to finish the install. The water pump was pretty easy to do. It was just a pain getting there. We really struggled with the fan clutch nut. I finally rented two tools from our local auto parts store and we got it. After we got the whole system was back together, we started pouring coolant into the radiator, then a gush of coolant came out from around the lower thermostat housing. The stupid thermostat had slid out of it's location and was pinned between the housing and the block. So frustrating. I had added a bit of RTV to the thermostat to keep it in place. I did this again, adding more. Everything is back together this time. I hope it seals. We used a gasket and a thin layer of the Permatex Aviation Form-A-Gasket mentioned about by @Mike_H. I'm waiting 4 hours before filling it with coolant again. I really hope this works.

 

[JMT]

Well, that didn’t work. I’ve tried a Fel-Pro Gasket with the permatex aviation form a gasket, 1Fel Pro without the permatex, 1 off brand gasket, then 2 off brand gaskets at the same time. Torque to 17ft/lbs. Still won’t seal. I’m so done. I’m getting The Right Stuff, making a bead and shutting this shit down. I’ve laid CC edges down and the mating surface on the block looks good. It’s a brand new housing. I’m sooooooooooo tired of this. 10 hours on the stupid cooling system and even when I do get it sealed, who knows if it’s fixed. Bleeped-y-bleep bleep bleepbleep

 

[Trevlaw]

Well, that didn’t work. I’ve tried a Fel-Pro Gasket with the permatex aviation form a gasket, 1Fel Pro without the permatex, 1 off brand gasket, then 2 off brand gaskets at the same time. Torque to 17ft/lbs. Still won’t seal. I’m so done. I’m getting The Right Stuff, making a bead and shutting this shit down. I’ve laid CC edges down and the mating surface on the block looks good. It’s a brand new housing. I’m sooooooooooo tired of this. 10 hours on the stupid cooling system and even when I do get it sealed, who knows if it’s fixed. Bleeped-y-bleep bleep bleepbleep

Did you check the new housing to see if it's flat?

 

[williambmac]

the housing you bought, is it a mopar or aftermarket housing?

I've had coolant leaks on two jeeps when using the aftermarket thermostat housings.

 

[JMT]

Did you check the new housing to see if it's flat?

No, just the engine side. I used The Right Stuff 1 minute gasket maker and it’s done, no leaks. The system burped. It’s cooling! 210* and holding. Woohoo! Boys happy, very good outcome.

 

[bobthetj03]

Glad you got it sorted out buddy!
Weired how that housing wasn't sealing.

 

[Irun]

About to finish the install. The water pump was pretty easy to do. It was just a pain getting there. We really struggled with the fan clutch nut. I finally rented two tools from our local auto parts store and we got it. After we got the whole system was back together, we started pouring coolant into the radiator, then a gush of coolant came out from around the lower thermostat housing. The stupid thermostat had slid out of it's location and was pinned between the housing and the block. So frustrating. I had added a bit of RTV to the thermostat to keep it in place. I did this again, adding more. Everything is back together this time. I hope it seals. We used a gasket and a thin layer of the Permatex Aviation Form-A-Gasket mentioned about by @Mike_H. I'm waiting 4 hours before filling it with coolant again. I really hope this works.

A little late now, but this is hands down the best tool I've ever used for getting the fan clutch nut loose. One or two short bursts of the trigger and it comes loose every time!

https://www.harborfreight.com/air-i...92oFK9otOrNJLWBABHLLc12-NRidFtjoaAkRgEALw_wcB