[Bummo]

Cant figure this out. When I am idling in gear at a light temp guage goes to lower 1/4 of guage. When I start driving, even slowly (or fast) the temp climbs to upper 1/4 or even 1/8 of guage. It even pins itself hot sometimes, but goes down as soon as I stop moving. This is the opposite of the cooling problems from old beaters in the past. I believe (because of underhood heat) that the guage is ok, and the timing seems fine. Starts and idles and accelerates fine. But when this temp guage pins (often when I just slow down) it will start steaming and pissing if It doesnt fix that situation by stopping immediately or it dropping a little by driving again. It just boggles me. And I'm straight and dont like to be boggled.

 

[RAMMAN4]

Check your thermostat. It might be plugged and the extra effort of going fast could be causing the motor to overheat because the coolant isn't passing fast enough through the thermostat.

 

[Bummo]

Ya, I'm gonna pull it and change the upper rad hose which seems a little soft. Might be collapsing somehow. Weird though.

 

[macario]

If your gauge is the factory gauge, verify that it is working by installing a mechanical temp gauge otherwise you are just guessing.

Mac

 

[Evildriver-3]

Yeah get a baster thermometer toss it in the rad and see if it goes up or down, then get a auto meter mechanical temp guage

 

[Bummo]

Well, I had to go get this utility PU box trailer I bought so I didnt have too much time. So I pulled the thermostat and went. Temp never got past half but still acted funny. Colder at idle then at cruise. No indications its head gasket but I'm starting to wonder.

 

[RAMMAN4]

Fill up your coolant system all the way and leave the cap off. Start the truck and let it run and go watch the coolant then. If the coolant pulses it's a sign you could have a blown head gasket.

 

[Bummo]

I will do that tommorrow. Thanks.

 

[DDGRC84]

also check the LOWER rad hose, it can collapse from the suction of the water pump.

Jake

 

[TheRamChargerMan]

does it get cooler with rpm, or speed IE can you rev it and get it to heat up while sitting still ??

Check your fan clutch, it may only be engaging at low rpm if it is going bad, and make sure the coolant system is completely filled. IS your radiator plugged (the cooling fins) with mud or trash ?? Do you have a fan shroud on the radiator ??

 

[Ram]

Do you have heat inside the cab? And is your radiator cap tight? Could have a bad cap spring not allowing enough pressure to build up inside the cooling system. Have you noticed what the over flow bottle has been doing lately? Or do you have one? If not my want to install one to see if your having to add more coolant, and to see how much you may be loosing!

 

[3jvj]

sound like a fan clutch. If it has failed it won't cool when your engine spins fast. You can probably test by idling up your engine in nuetral (or use a phototach- your fan speed should match engine rpm when it is hot). If your lower hose is within 10 -15 degrees of your upper hose it is good sign your fan clutch is gone too (no air flow = no cooling). I've had one go before, and I could drive all day long under 55mph no problem, go 56 and up and it got hot.