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Discussion Starter · #1 ·
I've been having overheating issues for the last couple of days. My rig has 195k on it with no mods 3.7 It has a brand new thermostat and recently bought a radiator because I found a small leak. Hoping the radiator would fix my problem it didn't. I have no check engine light on no missing and everything seems to be fine no noises at all. My heat doesnt work at all and once it runs at 2500 rpms for a little bit (4 minutes or so) it sky rockets. Need help this is annoying and my only way to work for now.
 

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07Lifted,4X4,6sp-man,3.7L
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Sounds like air trapped in the system.

There is an air bleed located at the upper radiator hose where it comes from the engine (3.7). Open the bleeder when engine and coolant is cold. Fill radiator till fluid comes out the bleeder. Close bleeder. Also fill the reservoir.
This will get most air out. But to effectively deaerate the system, multiple hot, then cool down cycles of the system may be required.
Idling will not deaerate the system.
Normal driving... After it reaches operating temp shut the rig off and let it completely cool down, then refill the reservoir. Repeat 3 times.

Or maybe the water pump impeller is shot.
 
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Discussion Starter · #3 ·
Sounds like air trapped in the system.

There is an air bleed located at the upper radiator hose where it comes from the engine (3.7). Open the bleeder when engine and coolant is cold. Fill radiator till fluid comes out the bleeder. Close bleeder. Also fill the reservoir.
This will get most air out. But to effectively deaerate the system, multiple hot, then cool down cycles of the system may be required.
Idling will not deaerate the system.
Normal driving... After it reaches operating temp shut the rig off and let it completely cool down, then refill the reservoir. Repeat 3 times.

Or maybe the water pump impeller is shot.
So I believe I've finally found the problem after days and days of troubleshooting. It's only heating up while driving down the road when at idle it cools itself back down. I believe it could be the high speed fan relay switch. I was told the nitros have 2 speeds for their electric fan one low speed when running at low temp and one high speed for when it starts to warm up/over heats. The guy (my landlord who is a licensed mechanic) said that the relay may be shot. I'm wondering if anyone else has had this problem or if that sounds accurate.
Edit: the waterpump is working perfectly and I did have air in the system but finally got it bled out.
 

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07Lifted,4X4,6sp-man,3.7L
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Do you have a viscus fan attached to the water pump?
I assume you checked the fan fuses.
There are 2 relays for the fan, Low speed (inside the TIPM(fuse box)), and High speed, under and inboard of the RF headlight.
Use caution when working with that relay, there is an impact sensor located right next to it.

2 is relay, 1 impact sensor.
 
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Discussion Starter · #5 ·
Do you have a viscus fan attached to the water pump?
I assume you checked the fan fuses.
There are 2 relays for the fan, Low speed (inside the TIPM(fuse box)), and High speed, under and inboard of the RF headlight.
Use caution when working with that relay, there is an impact sensor located right next to it.

2 is relay, 1 impact sensor.
Ok I took it out pecked on it a few times and my highspeed fan is now work lol. But still slightly overheating. Before it overheated this time I heard a slight clicking news while running the ac like something was kicking on and off. It isnt too hot to drive but still not in my comfort zone
 

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07Lifted,4X4,6sp-man,3.7L
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Clicking noise was likely the A/C clutch engaging and disengaging.
I was asking about the viscus fan because when driving it should not spin, or spin just a little.

That temp is not bad. It may just be the angle of the Pic. In which case it is centered.
You could try cleaning the Rad fins by spraying water thru them from the rear.
 
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Discussion Starter · #7 ·
I have no clue. I took the belt off and turned the water pump by hand easily if that tells you anything. (While holding it at 2500 rpm it slowly overheats [while parked] which when driving in 6th gear it usully runs 2k-2100 at 60mph.) It was cooling itself down last night while parked but now it is just setting at the same temp once it climbs.
 

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07Lifted,4X4,6sp-man,3.7L
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Sorry I was editing my previous post while you were typing.
See above again...
If you had a viscus fan you would know. It connects to the front of the water pump.
It looks pretty good temp wise.
 
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Discussion Starter · #9 ·
Sorry I was editing my previous post while you were typing.
See above again...
If you had a viscus fan you would know. It connects to the front of the water pump.
It looks pretty good temp wise.
It went up another 2 notches after holding the rpms at 2500 for just a couple minutes
 

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Discussion Starter · #10 ·
I'm going to just get up real early while it's cool and try to drive it to my families shop that way I can find and fix the problem. This has been frustrating me and where I'm at I dont have the tools or area to work on it I just have my emergency kit. Once I find and fix the problem I'll repost on here showing how I solved it for future references. Thanks a bunch for all the help and suggestions!
 

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07Lifted,4X4,6sp-man,3.7L
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I'd start by replacing that sticking relay and go from there.
Then clean the fins of the condenser. (Sorry forgot you had a new Rad...)

One more thought. Are all the cowls around the radiator in place?
 

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Discussion Starter · #13 ·
Alas problem solved. The waterpump was the problem. It wasnt pulling enough water through it so, we took the old thermostat and cut the center out so we could run it without a thermostat. Now that the waterpump doesnt have to pump so hard it isnt overheating plan on buying and replacing next weekend. I may have inflicted this apon myself by trying to figure out what was going on when it still had air in the system. For future references to anyone after changing the radiator/ fluid be sure to bleed the air out, the bleeder valve is located at the end of the hose running on top of the motor. Pour water in your radiator until water flows smoothly out of the bleeder . Thanks for all the help guys hopefully this thread will help someone else.
 

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07Lifted,4X4,6sp-man,3.7L
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Dang! Two success stories in one day.
Thanks for getting back to us with the cause. It will help others down the line.
 
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