Heat problem after replacing all the goodies (2 Viewers)

[tock13]

I did a search on this and kinda got an asnwer but still wanna throw it out there to see if I missed anything. My temp guage in my 40 ran between the first line with the c above it an the next hash mark all the time regardless of outside temp...driving highway speeds it creeped up a little but never much. The hoses were some f'd up mix of hoses from something else that were cut to fit and on the way out so I replaced everything with new. Removed the rad drain plug and nothing...the hole was blocked with black hard crud so I took piece of coat hanger and gently got it to break. drained everything, the coolant looked fine. After replacing hoses, thermostat , both gaskets and temp sensor with oem stuff from the dealer I filled it 50/50 with coolant and went for a ride. no leaks but it drives way hot. the temp guage gets hot within a mile...never did that before. hits straight up and creeps towards the last line regardless of speed. I know the guage is right because I cant hold the upper hose for more then 2 seconds right after I turn it off after a drive cuz it is freaking hot. I thought maybe the radiator was to blame...but it worked fine before...bad thermostat out of the box? What do you guys think?? any suggestions?

 

[spotcruiser]

If the top rad hose is hot, your thermostat is open. Maybe not all the way, but it is open.

Have you verified the actual coolant temp? Run it with the cap off and check actual temp when the thermo opens. Should start seeing somewhere near 180 when it starts to open and could go to 200 or slightly above. Borrow the old lady's cooking thermometer if you have to.

Sure you got the correct temp sender?

 

[Landpimp]

I would burp the coolent system, jack or park with the front end up, take the cap off the rad, turn the heater(s) on, and let it run for a while(like an hour), might just be an air pocket.

there is a chance you got the wrong temp sensor, for an earlier or latter motor.

chance the t-stat is bad.

after shut off the temps will climb quite a bit for a while, so thats not a problem in itself.

can you hold the upper hose when its running?

possiblly the rad cap is bad.

 

[tock13]

Thanks for the replys...

I threw the old sensor back in it and same problem. I ran it and noticed that the top half of the rad was quite hot the bottom half warm to cool to the touch.

I cant keep my hand on the hose when it is running cuz it's still too hot. I will try your suggestions Pimp and see what happens...might try the old h-stat too. I am strating to hear the "wouldnt a new wrangler be less hassle and just run??" from the better half again. ahhhh...she makes me smile.

 

[raoul reese]

heat issues

I would look hard at my hoses if the hose at the bottom of the radiator is soft or crimps you will have heat issues.

 

[tock13]

All the hoses are new and run straight with no kinks. I was bored so I removed the rad and flushed it and it was really clean. It must be trapped air or a bad t-stat. oh well...back to it.

 

[spotcruiser]

Just to check, this is a 2F and not a 350, right?

 

[tock13]

oh yeah...stock 2f. I am putting it all back together today...we shall see.

 

[ian]

cavitation

Temp differences in radiator makes it sound like cavitation due to blockage or huge air pocket. Any particulate evident during flush? I've seen stop leak do terrible things to radiators (and the rest of the coolant system).

I suppose it's also possible that there's no flow (along lines of previous reference to hose kink). Anyone know of a good way to tell if your water pump is doing its job (other than engine overheating) ??

 

[crewzerdog]

Needs a burp

As Landpimp says - most likely an air pocket in the system - happened to me and was not able to eliminate the problem until I opened up my heater valve - guess that allowed fluid/air to migrate through the system.

Second item I had to replace was a faulty NEW thermostat -- learned the hard way as I will always check these using pot of hot water on the stove with digital thermometer before installing to make sure - my NEW thermostat was off by some 15+ degrees. These two items substantially reduced the temps at idle and cruising around town but truck still did get much hotter at interstate speeds.

Final fix for me was replacing the fan clutch. After fan clutch replacement it runs much much cooler. Good Luck..

 

[tock13]

thanks for all the replies. I got it back together and it runs at the first line but gets hotter when I run it hard where the needle is straight up a tad more. I tried to get the front up to get the air out if there was any. I will put the old t-stat back in and be back to square one except for brand new hoses. to see where I sit. There was nothing ugly about the flushing of the system...pretty clean. Is there a way to tell if the fan clutch is bad? When I had it off it had resistance when I spun it. Runs hotter when I turn rear heater on so I am thinking there must be air in there somewhere. thanks again for the ideas