[wyoranch]

Ok guys. I have to replace my radiator. Rear ended another truck in a mud hole and pushed mine into my fan. Got a brand new all aluminum 3 core on the way. I want to do this right, so I figured I should clean out the rust in my coolant passages in my motor if I could. Whats the best way to do this?

 

[brothermo]

When I replaced the radiator on my truck, I just flushed the cooling system with water until it came out clear. Then I went to a coolant/water mixture and flushed until it had circulated through.

That was two years ago, and the cooling system has worked great.

 

[Alvin in AZ]

When I replaced the radiator on my truck, I just flushed the cooling system
with water until it came out clear. Then I went to a coolant/water mixture
and flushed until it had circulated through.
That was two years ago, and the cooling system has worked great.

Glad it's worked out great for you but I got a story for you.
I bought a 390FE, got it home and set it on my hick engine stand...

...pulled the drain plugs on both sides of the block and the water pump too.
Ran tap water through it like I meant business ran pretty and clear but just
as it'd begin running out of water to drain, it'd get all goopy and rusty.

Did that over and over and over and finally knocked out the freeze plugs
and found the sucker still plumb -full- of goopy rusty crap! :/

I'm guessing that aluminum stuff had been added at some point?
Or some other type of cooling system stop leak crap?

All I know for sure is, no amount of flushing would clean it, it took reaching
into the water jacket with a piece of wire (and I don't remember what all I
used) to clean that crap out of there. No kidding. Circulation was stopped
down into the lower reaches of the water jacket!

So the moral of the story is watch to see how clear the water runs as it's
finishing up?

------------------------

While I had my 360FE out of the truck I drilled and tapped both the drain
plugs' holes from 1/4" pipe to 3/8" pipe and use plugs with square heads.
So I use anti-seize on the threads and a 7/16" 8-point 1/2" drive socket
and I've never had a problem with them being a pain to get out. Since I
bought it new I'd hated those sorry little plugs with the Allen socket heads
the factory installed. YMMV

Alvin in AZ