My truck is overheating, obviously. Idling, it doesn't over heat or if it does, very slowly unless I turn on the a/c and give it some gas.

I replaced the heater core last year.. and no signs (antifreeze on passenger floor, etc) that it's bad again. I replaced the thermostat 2 days ago. The water pump is circulating o.k...

So what in the WORLD is going on?
My brother told me that there's probably air in the radiator somewhere. He said to fill it with antifreeze slowly.. and it'll seem like I'm putting a lot in there but to keep doing it to get the air out.

It DOES gurgle when it over heats. And then he said to let it overheat a time or two and it should be fine, but nothing's working and the radiator and hoses aren't leaking.

What in the WORLD is going on?

Quote:

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Originally Posted by MKL1980

My truck is overheating, obviously. Idling, it doesn't over heat or if it does, very slowly unless I turn on the a/c and give it some gas.

I replaced the heater core last year..and no signs (antifreeze on passenger floor, etc) that it's bad again. I replaced the thermostat 2 days ago. The water pump is circulating o.k....

So what in the WORLD is going on?
My brother told me that there's probably air in the radiator somewhere. He said to fill it with antifreeze slowly..and it'll seem like I'm putting alot in there but to keep doing it to get the air out.

It DOES gurgle when it over heats. And then he said to let it overheat a time or two and it should be fine, but nothing's working and the radiator and hoses aren't leaking.

What in the WORLD is going on?

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The problem may not be air in the radiator. The radiator on a vehicle of that age may have become congested. Corrosion and debris settles into the core, stemming the flow of coolant, resulting in poor heat transfer.
A tech can "see" this problem with and infra-red thermometer by scanning the rad, looking for cold spots when the system is otherwise hot.

Replace radiator--likely blockage, due to corrosion or mineral buildup. Refill with a 50/50 mixture of antifreeze and distilled water.