I'm trying to flush the coolant out of my 01 ranger with 85k miles. I'm fairly certain it's never been done before as the coolant is filthy and it was a farm truck that wasn't maintained very well before I bought it. I got most of the coolant drained, but there's still a bit in the resovoir that won't drain out ( i assume due to a blockage). I tried using a garden hose in the resovoir, still nothing.

My question is, is it safe to run the motor briefly with next to 0 coolant to try and clear the blockage? Not talking about driving it anywhere, just let it warm up to normal operating temp then shut it down.

 

I would say no, for a few moments, yes, but not until it warms up, it'll fry it.

What do you mean about some left in the reservoir? the plastic expansion tank? Running the engine wouldn't help that anyway - have you removed the pipe from the bottom?

 

Yeah I believe that's what it's called, right in front of the washer fluid tank. There's still some coolant left over in there that didn't drain out. I tried running water from a garden hose into it, but it just filled the tank more. I was going to remove the hose but wasn't sure how to keep it from pouring out everywhere.

EDIT: After reading up on it a bit more, I've realized that the expansion tank does not drain with the rest of the system, and needs to be drained separately using the hose that attaches to the radiator cap. That will most likely solve my issue!

 

It is called the Overflow or reservoir tank, degas or expansion tank is different.

Yes take that hose off the rad cap opening and BLOW thru it, then put that end down lower than the bottom on the overflow tank and water will drain out, put garden hose in tank to rinse it as it drains

 

Problem solved :)