High Engine Temp?

[Kigiin]

I was stuck in the traffic jam from hell this morning - I-75 shut down between Dayton and Cincinnati.

The outside temp was only about 70 but about an hour into the jam, my water temp was max'ed out. No check lights came on or anything unusual as far as the truck's operation. It did returned to normal temp after getting moving (3 hours into the jam, I gave up and u-turned), and has been fine all day.

Is this normal or is there a problem?

 

[spressomon]

Are you basing your over heating on a Scangauge reading or the OEM temp gauge?

If it is overheating at or near idle and assuming your radiator is in good shape with the proper type and level of coolant, etc., then it might be your fan clutch.

One way to check the fan clutch: When the engine is hot...turn the engine off and immediately try to turn the radiator fan by hand. It shouldn't move. If it spins freely then you probably either need to replace the fan clutch or replace the fan clutch fluid as I am doing right now!

 

[Liam]

Fan Clutch.....change it out.

 

[Kigiin]

I was just going by the water temp gauge on the dash - it was pegged.

I was able to spin the fan after driving it for about 20-25 minutes - assume that was enough time to get it hot enough.

How about a thermostat problem?

 

[Tools R Us]

... I was able to spin the fan after driving it for about 20-25 minutes - assume that was enough time to get it hot enough.

It depends on temp, load, speed, etc. The clutch is thermostat controlled, so the airflow temp that the clutch is seeing is what dictates when it's engaged. IMHO the best way to test is the "apply pressure to the fan attempting to stop it, with the motor running" test.

The best way that I have found to get it warm enough to test; park in the sun roll down all of the windows turn on all load accessories, A/C to Max, etc. Run at idle until warm, quickly open the hood and test. If the ambient temp is cool may need to block some of the grill to get it warm enough.

How about a thermostat problem?

Maybe, but yours sounds like sound like a classic case of not enough cooling capacity. Most cases caused by ether; insufficient water to air interchange, ie clogged radiator and/or low airflow, ie bad fan clutch fluid. Most times when thermostats fail they are dead, the motor will overheat when the rig is driven regardless of load, speed, etc. Newer thermostats are very reliable, rarely fail.

 

[Trunk Monkey]

You realize you shouldn't drive it with the coolant temp. that high? Pull over, shut it off, open the hood. If it's starting to overheat you can sometimes blast the heater (fun in the summer) and that helps.

 

[Kigiin]

You realize you shouldn't drive it with the coolant temp. that high? Pull over, shut it off, open the hood. If it's starting to overheat you can sometimes blast the heater (fun in the summer) and that helps.

Well fortunately I was able to shut it off, but I didn't have to pull over. In 3 hours, I traveled less than 20 miles, and at one point didn't move for 50 minutes.

It depends on temp, load, speed, etc. The clutch is thermostat controlled, so the airflow temp that the clutch is seeing is what dictates when it's engaged. IMHO the best way to test is the "apply pressure to the fan attempting to stop it, with the motor running" test.

The best way that I have found to get it warm enough to test; park in the sun roll down all of the windows turn on all load accessories, A/C to Max, etc. Run at idle until warm, quickly open the hood and test. If the ambient temp is cool may need to block some of the grill to get it warm enough.

I am not sure I understand... "applied pressure to the fan to try to stop it"? And what does it mean if I can stop it or not?

Thanks

 

[Liam]

I am not sure I understand... "applied pressure to the fan to try to stop it"? And what does it mean if I can stop it or not?

Thanks

it means while the fan is spinning stick your hand in there and try to stop it....or your tongue.

 

[Kigiin]

it means while the fan is spinning stick your hand in there and try to stop it....or your tongue.

Seriously. I don't think I could get my tongue in there, but definitely the johnson

 

[Kigiin]

Replaced the fan clutch yesterday, but after sitting idle for about 5-10 minutes this afternoon the water temp gauge again went into the red (AC was on). Mechanic said he tested after replacing it, but wasn't sure if AC was on.

I think fan clutch did need to be replaced, however am now thinking thermostat.

Any thoughts on what else it could be?

 

[Trunk Monkey]

I'd go thermostat next and flush the fluid while you're doing that. Then I'd check your water pump.

 

[Kigiin]

The water pump and timing belt were just replaced (around 95K miles - I did it based on time not mileage).

Thanks

 

[Liam]

go for the Thermo.

I've got a question. You had a mechanic replace the fan clutch and he didnt tell you that the one you had in there was good or not? I think he could tell if it was the fan clutch or not............s****s mechanic.

 

[Kigiin]

go for the Thermo.

I've got a question. You had a mechanic replace the fan clutch and he didnt tell you that the one you had in there was good or not? I think he could tell if it was the fan clutch or not............****ass mechanic.

As I said, the fan clutch was bad - it displayed all the symptoms.

 

[Liam]

R

I think fan clutch did need to be replaced

As I said, the fan clutch was bad - it displayed all the symptoms.

"i think" is not certain. Believe me i've thought a lot of things and i was wrong. I just hope the mechanic just didnt swap it out without testing it himself. That would be money not well spent.

for the record, I replaced the original fan clutch in my 78 fj40 5 years ago, maybe 6...

 

[Kigiin]

Thermostat completed the solution - case closed.

Thanks for the help.

 

[Liam]

Thermostat completed the solution - case closed.

Thanks for the help.

you're welcome.......lol