Radiator - Flush or replace?

JTH1972 · Jan 17, 2009

Okay, I had planned on changing my thermostat today, but instead of coolant coming out of the drain, I got this brown sludge slowly dripping out (and I do mean slowly!). Coolant on the top is nice and green, but this stuff is... ugh. I'm wondering how bad the rest of the system is.

So besides the obvious flush to clean out the block, should I try my luck and see if the rad will flush out too, or am I further ahead to just repalce it if it looks this bad?

cr_the_machinist · Jan 17, 2009

I'd say just flush it. That coolant will start to break down after a while if it is not flushed out with new coolant. If you have not had any running problems just flush it out and clean out the radiator.

Sasquatch_Ryda · Jan 17, 2009

Run some rad flush in it for a while, then drain it and back flush the rad out.

LearjetMinako · Jan 17, 2009

Use a radiator flush, then take a garden hose and just keep flushing it with clean water until it comes out clear. Do this with the engine running and heater on. And back flushing the radiator helps too.

Did this on my mom's 96' Blazer. I didn't realize how far broken down the dex-cool became until I saw the brown color coming out. Won't happen again, no more dex-cool. Go old fashion Prestone green coolant for all makes.

JTH1972 · Jan 18, 2009

ok I'll give that a try first. thanks for the replies. Hopefully it'll get out most of the rust and crap that's clearly in there. Is there any way of cleaning out the drain petcock?

Radiator - Flush or replace?

JTH1972

15+ Year Member

cr_the_machinist

15+ Year Member

Sasquatch_Ryda

TRS Staff - Retired

LearjetMinako

15+ Year Member

JTH1972

15+ Year Member

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