86' CJ7 laredo

[bdunnam]

My jeep is running hot when going down the highway when the rpms are kept above 1700. It is doing the opposite of anything i've ever seen you can let it sit and idle for several hours and it'll never miss a lick and stay on the cool side of the temp guage, but goin down the highway it'll get to the point where i watch the guage like a hawk because it gets so close to the hot mark. somebody please help

 

[FamousJerry]

Did you try a simple sending unit replacement? or will the jeep actually over heat?

 

[Old Dog]

what kind of fan do you have?
I see you have a winch, it could be blocking the air flow.

 

[bdunnam]

Well it has a new sending unit, probably a month old. and the fan is the original clutch fan it is frozen up and might as well be a straight fan, it has a fan shroud and sucks plenty of air supposedly there is some trick where u can drop like a napkin or rag or something and if it gets sucked to the radiator it should get plenty of air and it sucks air about like a turbine jet engine. Another thing for thought is i cant figure out why my oil pressure sits between 60 and 80 psi it also has a new unit

 

[bdunnam]

Re: 86' CJ7 running hot

Well I drove it today down the highway running about 70, having to keep it in 3rd gear b/c 4th is too high and the motor will not hold out, but i made it about 7 miles and the dang thing overheated i kept my eye on the guage noticing it getting hotter than it ever had and then caught a whiff of coolant. luckily no blown hoses anywhere or leaks but it was shooting fluid out of the over flow box like crazy. Well when i got to where i could pull over i noticed coolant all down the drivers side from where it overflowed and the fan just shot it out from under the hood. I really need help with this one its a@$ backwards from anything i've ever seen or heard of before.

 

[mylittlecj5]

Re: 86' CJ7 running hot

have you checked the timing under a load?
And replace that bad clutch fan. Its designed to slow down when there is enough airflow thru the radiator, giving you a little better MPG and decreasing the noise factor. It may even help with the original problem.

 

[CJ]

Re: 86' CJ7 running hot

I bet the lower hose does not have a spring in it to keep the hose open. Under higher RPM's it can collapse from the suction of the water pump. I have seen this happen before.

 

[dalefan88]

do you hear the belt slipping at higher rpms?

 

[Cheepjeep85]

Re: 86' CJ7 running hot

I bet the lower hose does not have a spring in it to keep the hose open. Under higher RPM's it can collapse from the suction of the water pump. I have seen this happen before.

yep had this happen to. i bet the hoses have never been replaced, if they have its probably been a long time.

 

[bdunnam]

Re: 86' CJ7 running hot

well i have replaced both top and bottom radiator hoses within the last 2 years i know but i will get a new fan this week and i will check the bottom hose for a spring because i dont remember seeing one in there when i replaced it. and i have never heard the belt slipping at all unless it was the alternator.

 

[bdunnam]

Re: 86' CJ7 running hot

well i have tried everything recommended and nothing i think it may have even gotten worse. I drove to my grandfathers house roughly 10 mi. from town and replaced my bottom hose there, well about 2 miles into it started to get hot, well bout the time i pulled in the driveway at my shop it had gotten so hot that the engine started knockin. Well i parked it that night and came back the next day and took the thermostat out and supposedly they arent supposed to get hot, but mine did will it didnt get hot but it was running above operating tempurature. So now i have ordered a new water pump, and im thinking that this could be it, but im also gona bend the float up on my carb too, because supposedly itll idle at the right mixture but going down the highway it may be running too lean.