Radiator Mud: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Jan. 13, 2012 4:02 p.m. ultraclyde HalfDork

I'm replacing the radiator in my mother's 96 (1.6L) Corrolla since it has cracked the plastic end tank. It has also developed a case of brown crud in the coolant (and all over the front end where it leaks.) Seriously, this stuff looks like river mud. She's never put any additives in it and swears no one else has either, but I'm not guaranteeing that's true. No sign of coolant in the oil, and no tell-tale coolant bubbles and burps in the radiator so I don't thing it's a blown head gasket. the car runs...well, like crap, but not like the engine is hurt. Still gets up to HWY speeds and doesn't run hot as long as you don't let it get low from the leak.

So, how should I go about flushing the block? Pull the radiator and then hook a garden hose to the radiator hose, run the engine untilt the water's clear?

Am I missing something important with the mudslide?

Any good tips and tricks?
Jan. 13, 2012 4:06 p.m. Streetwiseguy SuperDork

Thick viscous mud that might seem like a mixture of coolant and oil floating on top, or a general icky brown coolant through the whole system?
Jan. 13, 2012 4:15 p.m. noddaz Reader

My guess is this is the result if the car has not had the coolant replaced even on a semi regular basis.... Stick a hose in the lower hose opening and block off what leaks around the hose with a rag... Then do the same where the top hose hooks up. Yes, you will get wet. Drain what you can out of the engine, hook up the new radiator and refill with fresh coolant.
Jan. 13, 2012 4:23 p.m. Taiden SuperDork

noddaz wrote:

My guess is this is the result if the car has not had the coolant replaced even on a semi regular basis.... Stick a hose in the lower hose opening and block off what leaks around the hose with a rag... Then do the same where the top hose hooks up. Yes, you will get wet. Drain what you can out of the engine, hook up the new radiator and refill with fresh coolant.

I did this with a Saab radiator I bought used.

First time I ran it, brown came out like crazy for about 30 seconds. Then it ran clear.

Then I reverse flushed it, and it ran just as brown for about 15 seconds. Then it ran clear.

Then I squirted some Dawn down the inlet and flushed it again. It ran brown for about 10 seconds. Then it ran clear.

Reverse flushed it again, it ran clear. I let it run until no more suds came out.

It was pretty fun actually. I was amazed at how much crap there was in there.
Jan. 13, 2012 4:26 p.m. HappyAndy HalfDork

Didn't a lot of toyotas use dexcool? Sounds like dexcool gone bad. For a mild case of deathcool contamination I completely drain the cooling system including the block if possible, then flush it with water and run it for a few hours on just water, then completely drain it again & refill it with a 50/50 mix of regular coolant/water.

The dexcool becomes very corrosive when it gets contaminated, which happens just by looking at the wrong way. The "mud" is the combination of the bad coolant and all the crud that its dissolved out of your engines insides. I've seen a GM 4.3 V6 literally rusted to failure from the inside out by dexcool.

For that reason I'd be leery about using a cooling system flushing chemical. OTOH Toyota engines are probably made from better metals than GM engines so maybe that won't be a problem.
Jan. 13, 2012 6:46 p.m. ValuePack Dork

I don't remember Dexcool, but I do recall the specific "Toyota Red"(I'm sure it had a better name than that). I was only a Toyota owner for a few years, take my generally uninformed opinion worth a grain of salt, I may be very much mistaken.

Sounds like it's just expired coolant and random junk in the system. Garden hose method, throw it all back together, see how she flies.
Jan. 13, 2012 9:05 p.m. tuna55 SuperDork

If they used Dexcool get it all out and get it out now - that stuff is positively evil. I can't image how that got by testing at GM.

"Hey we have this perfectly reliable small block and V6 variant, is it a problem that after a decade or so the coolant turns into an extremely corrosive solid?"
Jan. 13, 2012 10:04 p.m. Appleseed SuperDork

DEXcool = septic tank E36 M3. Ask me how I know.
Jan. 14, 2012 10:38 a.m. dean1484 SuperDork

tuna55 wrote:

If they used Dexcool get it all out and get it out now - that stuff is positively evil. I can't image how that got by testing at GM.

"Hey we have this perfectly reliable small block and V6 variant, is it a problem that after a decade or so the coolant turns into an extremely corrosive solid?"

Guaranteed obsolescence.
Jan. 14, 2012 10:44 a.m. DILYSI Dave SuperDork

IIRC, there was a discussion about how to REALLY flush a cooling system, and vinegar was the go to.