Flushing/Degunking a cooling system.

[Tragic00 10+ year member]

Hello all. I got a '95 s10 (4.3L 4wd) that was recently passed on to me. The truck run great for the mileage (213k) but I noticed when checking the fluids the other evening the antifreeze looked horrid. From what I could tell from the looks is either a) head gasket leaking (though the oil is fine) or b) a mix match of antifreeze.

How could I go about flushing all this garbage out of it? I've heard there was solvents out there you could run through it to help clean everything out, but never heard of what they are or where to get them.

I was also told by someone to look into the Prestone Universal Flush 'n Fill kit [ THIS LINK ].

A little idea of what I am dealing with:

The coolant looks a brownish color, as well as tan colored lumps of what looks almost like play doe. The reservoir tank also looks heavily coated in it as well (was empty when I received it). I am assuming there is some blockage as well due to the temp rising and dropping at times while driving. Also the heater seems to have a mind of it's own, it blows out "warm" (not hot in anyway) air out, then seems to cold to a chilly breeze.

Anyone have any insight on this?

Thanks in advance!

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[IBTLover 10+ year member]

Those would be the Radiator Flush in the Coolant isle.

 

[Rich B 5,000+ posts]

That brown stuff could be remains from someone putting radiator stop leak in some time in the distant past.

Bars Leak is brown pellets in a brown fluid.

 

[pressnic38 10+ year member]

Is it chunks or is it a liquid?

 

[plugitin 5,000+ posts]

id say just change the fluid...if it was summer you could just run water in there for a bit and then switch back to anti freeze.

 

[-01limited- 10+ year member]

Be careful. someone mixed the orange and green coolant in one of my old vehicles, made gel balls and clogged my heater core and also caused my water pump to fail.

 

[plugitin 5,000+ posts]

Be careful. someone mixed the orange and green coolant in one of my old vehicles, made gel balls and clogged my heater core and also caused my water pump to fail.

you mean the mud looking stuff? Dex-cool?

 

[plugitin 5,000+ posts]

and btw, even if the oil is fine, your hg could still be bad...

 

[CHEMMINS 10+ year member]

Yes never mix dex-cool with standard glycol antifreeze.

Dex-cool is bad if your system is not set up for it. Stick with glycol based antifreeze.

 

[Tragic00 10+ year member]

Is it chunks or is it a liquid?

It's chunks.

 

[plugitin 5,000+ posts]

Yes never mix dex-cool with standard glycol antifreeze.
Dex-cool is bad if your system is not set up for it. Stick with glycol based antifreeze.

well, i know this...

and dex cool is bad, period.

 

[-01limited- 10+ year member]

you mean the mud looking stuff? Dex-cool?

Yes never mix dex-cool with standard glycol antifreeze.
Dex-cool is bad if your system is not set up for it. Stick with glycol based antifreeze.

well, i know this...
and dex cool is bad, period.

idk what it was but after I got the vehicle, 2 moths later it had already ruined my whole cooling system, heater core, radiator and water pump.

 

[06goat 10+ year member]

My guess is that it is original coolant, sometimes it can turn that ****** color, lumpy, just from being that old. Seent it. Just change it with 50 50 until summer like above said.

 

[audioatg 10+ year member]

Its a GM, It came with the Dex cool in it already. The gunky look is what happens to it over time. No services done to it.

Do this. Open anything and everything you can. Hoses, radiator, Pop the thermostat out housing as well off. And just flush flush flush with a hose of water. Until you get all that crap out. Then replace all hoses. ALL hoses. If its that junked up they will need to be replaced. After that. Add water to it with the coolant flush stuff you can get any place. And run that through there for a good time. Then drain all of that. Replace it with green coolant.

You wanna get all the Dex cool out before switching it to the green coolant.

 

[Tragic00 10+ year member]

and btw, even if the oil is fine, your hg could still be bad...

I do know this (exhaust side). We pressure tested it, the only point we got it to leak was @ 18psi and it was only a slight leak around the water pump mounting. Once I get this all cleared out I will be taking it off, cleaning and resealing it.

Its a GM, It came with the Dex cool in it already. The gunky look is what happens to it over time. No services done to it.
Do this. Open anything and everything you can. Hoses, radiator, Pop the thermostat out housing as well off. And just flush flush flush with a hose of water. Until you get all that crap out. Then replace all hoses. ALL hoses. If its that junked up they will need to be replaced. After that. Add water to it with the coolant flush stuff you can get any place. And run that through there for a good time. Then drain all of that. Replace it with green coolant.

You wanna get all the Dex cool out before switching it to the green coolant.

Did the '95's come with Dex Cool?