Preferred cooling system flush products.

[kodogtwh]

Any recommendations for a chemical flush? The cooling system (hoses, freeze plugs, head gaskets) in my truck are all top notch, however the internals of everything are coated in rusty garbage. I can flush it with straight water as many times as I like, and it will always come out brown. It's super soft stuff, I can easily wipe it off by hand, from what I can reach inside the radiator cap. No cooling issues, just a pet peeve.

If anyone has any input, feel free to share. Popular products, the "good stuff", the "cheap crap", all of it.

 

[19Walt93]

Whatever you end up using, make sure to pull both block drains and flush all of it out of the system afterwards, including the heater core. I've had better luck flushing with hot water, too.

 

[franklin2]

I had this problem. It was so bad when I first got the truck, the radiator would not even drain there was so much sediment in the bottom. Like you I cleaned it all out with a garden hose, I took the lower hose off and put the graden hose into the heater core hose and get running it till it cleared up. But later on I still had brown stuff coming out.

What I ended doing was just putting pure water in it, running it for a few days, draining it, flushing it, and then refilling it with pure water again. I did this several times over the period of several weeks till the water was clear. I then put the 50-50 mix in it and it was good after that. CAUTION!
My engine was bad and had a terrible amount of rust in it. When I finally got it cleaned out, the freeze plugs started leaking. I ended up pulling the engine and replacing all the freeze plugs. Been running good ever since.

 

[RobbieD]

I've used several different off-the-shelf parts store "flushing agents" over the years, but none stick out as better than another. I lean toward name-brand, and look for one that says it's OK to drive with for a day or two. I avoid anything that sounds like it's too aggressive (don't want to push my luck on 25 year old plus components).

My preferred method to actually flush is start with a cold engine, and start and run the engine a minute or two, to the point where the thermostat just opens (feel the hose) but the system hasn't pressurized yet.

Next step, loosen, then remove the radiator cap (do not let the system pressurize!). Then, quickly pop off the lower radiator hose (loosen the clamp prior to starting). The warm coolant comes puking out from two directions, along with a lot of the sediment which is suspended (not settled) from the water pump action and the coolant moving.

I'll repeat this procedure as many times as I think is needed, to get the cooling system reasonably clean. I've done it as much as 4 or 5 times over a couple of weeks on one of my "sludgier" trucks.

Sure, the petcock will drain the cooling system (slowly), but popping the lower hose will give it more of a "flush".

Seriously, on the older RBV trucks, keeping the cooling system in top shape is just as, if not more, important as changing the oil.

 

[superj]

If something is teal bad, i buy a bunch of store brand colas and pour them in after drianing. Let it sit and bubble everything and drain it out. Then do it again. After that clean it out with water a few times.

That was my last attempt cleaning for systems that didnt want to come clean.