Navajo Running Really Hot All of the Sudden

[Kirby N.]

I need some ideas. I am fresh out of ideas. My Navajo has always ran really cool since I got it 8 years ago. It never got to the middle of the guage. Always on the "c" side. Last year on the way to run Holy Cross Trail in Leadville, CO I noticed it was running hotter than normal. Like past the middle mark on the H side. So I was a little alarmed. It never overheated, it is just running hotter. Some things I tried:

1. Changed the thermostat to the coldest one I could find right away before I hit Holy Cross. I don't remember what the number was, but it was the lowest rated one I could find. I thought it was this because I can watch the guage get to its high point, then all of the sudden it cycles down and gets cool. Then the whole process starts over.

2. I changed the radiator. The radiator always seemed to leak but I could never find it. I had one out of a truck a parted out that was the thinner manual version. Since my truck is no longer an auto I flushed the manual radiator and threw it in. It doesn't leak, but it is at the same temp. if anything it runs a little hotter.


I am out of ideas. Has anyone else experienced this? Any suggestions? Today it was getting real close to the "h". It never overheated, but it is like 0 degrees today. I am a little concerned about trail ridding at 90 plus degrees idling along this summer. It will overheat in those conditions if it is running hot in 0 degrees for sure!

TIA

Kirby

 

[Dannyboy]

Fan Clutch. You need to get the loan a tool from Pep Boys to make it easy to change cause the Autozone one sucks.

Get the Heavy Duty fan clutch too, I changed mine and it made all the difference in the world, on both trucks.

 

[wood1]

Have you checked to make sure that your fan clutch is working properly? Also, do you have the same problem at highway speeds?

 

[Kirby N.]

I have the same problem at all speeds. Would it not be a problem at highway speeds if it was a clutch fan?

 

[Tbars4]

...it could be a radiator cap, blockage in your heater core, or even your temp sensor or guage...:scratch:

 

[Kirby N.]

I forgot I did change the cap twice too. It didn't help.

 

[Kirby N.]

Thanks for the suggestions. So I guess it could be 3 things:

1. The Gauge or the CTS

2. Blockage in the heater core

3. Fan Clutch

Would any other symptoms help me distinguish between one or the others?

I have a spare engine and it has a CTS and a fan on it. I could try those with out too much trouble... unless another symptom indicates the heater core...

 

[ThePhoenix]

could there be a bubble in the system? that used to be a common thing in my 68 mustang

 

[wood1]

At highway speed you shouldn't need the engine driven fan, if you are still running hot then you have another problem. I took the enging driven fan off of my 5.0 mustang and replaced it with an electirc and the only time it comes on, or has to, is slow traffic or stopped. (Or when you are driving it hard)

If you want to check the operation of the fan, let the engine come up to temperature, shut it off and try to turn the fan, if it turns too easily it needs to be replaced.

Was your old rad and the replacement scaled up inside? The tubes can become completely plugged from scale.

Can air go through the rad property? Is the shroud and fan working? There isn't anything blocking the air flow to the rad is there? Is coolant able to flow? Sometimes old rad hoses will flatten out from the suction of the water pump and constrict coolant flow. Also I have replaced thermostats and they weren't any good right out of the box. You can gently heat the copper cylinder of the thermostat with a propane torch or boiling water to verify it's operation.

If it's not any of these, you should check engine compression, you may have a cracked head or blown head gasket.

This is all assuming you have bled the air from the system and have a proper water/antifreeze mixture.

Good luck.

 

[ThePhoenix]

give her a burp....

 

[Kirby N.]

At highway speed you shouldn't need the engine driven fan, if you are still running hot then you have another problem. I took the enging driven fan off of my 5.0 mustang and replaced it with an electirc and the only time it comes on, or has to, is slow traffic or stopped. (Or when you are driving it hard)

If you want to check the operation of the fan, let the engine come up to temperature, shut it off and try to turn the fan, if it turns too easily it needs to be replaced.

Was your old rad and the replacement scaled up inside? The tubes can become completely plugged from scale.

Can air go through the rad property? Is the shroud and fan working? There isn't anything blocking the air flow to the rad is there? Is coolant able to flow? Sometimes old rad hoses will flatten out from the suction of the water pump and constrict coolant flow. Also I have replaced thermostats and they weren't any good right out of the box. You can gently heat the copper cylinder of the thermostat with a propane torch or boiling water to verify it's operation.

If it's not any of these, you should check engine compression, you may have a cracked head or blown head gasket.

This is all assuming you have bled the air from the system and have a proper water/antifreeze mixture.

Good luck.

The new and old radiator were a bit scaley, but I washed out the new one really well before I put it in. I put in a new lower Radiator hose too. The grill is clear in front of the radiator so I don't think that is it. The shroud is perfect too. I may try another thermostat, but I fear the worst! I think I may need to check the compression before I go driving it accross the country! I will get a guage and see what it tells me. I will do the fan clutch test first too!

thanks for all the help!

Kirby