Just bought a '99 F150 with 166k miles. The radiator fluid was brown / rusty so I drained it, used a can of Mac 1400 radiator cleaner from Napa to clean the system, flushed with clean water until the radiator drained clear, turned off engine, drained the radiator... so far so good.

The system should take 5 gals of coolant according to the owner's manual, but this barely took 1 1/2.
Ran the engine a bit, the level in the expansion tank didn't go down.
This, coupled with the fact that the old coolant was so brown with black bits (like old rubber hose particles) is concerning.
Any ideas?
Thanks, Tom

 

Did you just drain the radiator and not the engine block?

 

 

Hi,
No, I didn't drain the block. That's next on the list.

 

Don't have to drain the block if you use that kit.

 

That's good to know. I was also thinking of checking the thermostat to make sure that it was opening properly.