Cooling system

[Matt Dalton]

I recently bought a 1984 Bronco ii with 105,000 miles on it. Test drive was ok. It wasn’t until a week later I was driving up a very long hill that I saw the temperature raise to a very high level. Short story is I replaced the radiator cap, water pump, thermostat, belts, and flushed it. I got a fair amount of crud out of the system Radiator seems to be circulating fine through the radiator, but the temperature is still running hot on hills. I’m beginning to suspect the coolant journals in the block may be plugged. Does anyone have a suggestion for a different flush to use that would be more aggressive than the Prestone flush?

 

[RonD]

Welcome to TRS

Does temp climb a bit when idling?
Fan Clutch issue

You may need to pull out the radiator and do a Flip Test on it, just to take it off the table as the cause, which it most likely is.

If you have an automatic then you will need to cap/plug those lines after removing them from rad

Once rad is out it should be fully drained since lower hose was removed.

Shake it if you hear fluid it is coolant trapped in blocked passages

But do the Flip Test
It should be a side flow radiator, tubes run side to side, not up and down
Put rad cap on and turn rad on it side, tubes up and down
Put hand over lower hose opening
and fill rad using upper hose opening
When full stop filling and remove hand from lower hose
Should drain instantly

Now flip rad upside down, any water that comes out could only come from blocked passages.
You be the judge by how much water comes out.


You aren't hearing any Pinging when going uphill?

 

[Matt Dalton]

No pinging heard, but I don’t hear real well. But I will pay closer attention next time I drive it. Thank you for the reply.

 

[JerryC]

You could try the EvapoRust flush.
If you have ever used EvapoRust on rusty metal you can see how it might work in the motor.