Debris in Coolant

[Randy S.]

When the radiator was out of my 66 small block I backflushed the block. After installing a new radiator I did 3 hot flushes with distilled water and with heater on. The final flush I drained the radiator and filled with Prestone.
When I checked the freeze rating, I was surprised to see significant debris in the tester. Does the recovery tank catch a lot of sediment and I have an incorrect sample? Should I start over (a hassle to catch and recycle 4 gallons)or filter the fresh antifreeze mix thru a filter, like a coffee filter?

[Gene M.]

Re: Debris in Coolant

Randy,
I know it is a pain but the only way to flush out all the crap that collects in the cooling system is to remove the radiator and back flush it. I would also remove the drain plugs on the sides of the block and flush it till all clear water comes out. Suggest same to the heater core and aluminum tank.
You will be surprised at all the junk that comes out the block drain plug holes.

[Brian Monticello]

Re: Debris in Coolant

Here's the junk that came out of my block. I simply drained it into a bucket.

[William V.]

Re: Debris in Coolant (NASTY)

I'm glad I know what it is. Looks like something else.