Radiator flush with hose after overheating

Car got gummed up with some BlueDevil. Sort of like rock salt deposits all in the cooling system. I decided to flush the radiator out and do a few more things. First I took out the thermostat which was clogged up with a mixture of coolant and that gummy white BD stuff. Looked like it was stuck open as well. Cleaned around the thermostat with a rag and got the gunk out. I sealed the thermostat housing perimeter with sealant and screwed the housing back on without the thermostat. I plan to buy a new one, for the time being I am running without a thermostat. I then pulled the drain plug out and let the coolant drain. Lots of the rock salt type material came out. After that I put the drain plug back in and poured straight distilled water in the cooling system. About 2 gallons. Then I started the engine and poured in the peak: super cleaner+flush. It started to foam up , which I think is normal. It didn’t take all of it at first, had to wait for the water/remaining coolant to circulate. Then I drove the car for about 30 minutes with this mixture in there. Then parked it and left it overnight. Now I am wondering, should I drain the stuff in now or should I drain it along with a hose. I am thinking the hose might not be needed, it’s more of a traditional thing. But should draining it now and putting fresh 50/50 be enough. Or should I use a hose to get the remaining stuff out of the radiator?

Thank you


here’s what you should do . . .

fix the car the correct way, including a new thermostat and gasket

Why did you put it in . . . I’m assuming you put it in because you know the brand name. That means either you put it in, you watched somebody put in it, or somebody told you they put it in?

Blue devil and other products of that nature often have a tendency of plugging up passages, which cause cooling system problems

Blue devil usually gets used, in the hope of “fixing” a blown head gasket, for example

Was that the case here . . . ?

There’s still a lot of information missing, in my opinion

Model year

I addition to what db posted above, at this time I would recommend that you remove the radiator completely, lay it on the ground with the hose barbs up and the radiator cap on. Flush the radiator from the bottom to the top. If this is a GM, flush towards the radiator cap.

Then flush out the block, first from the top hose to the bottom hose, then remove the block drain and flush again, top to bottom. Let everything dry, replace the thermostat and re-install the radiator. Fill with a 50/50 or 2:1 ratio mix of universal longlife antifreeze to distilled water.

So far you have pretty much done exactly all the wrong things to this vehicle. You should have come here for advice for the original issue.

I’m thinking, at this point, blue devil plugged just about every conceivable cooling system passage

And I’d like to know what the underlying problem was

People don’t use blue devil if everything’s okay

I’m not sure of the post but think it was a head gasket issue db.

In the old days, I made a graduated hose fitting from a plastic flower watering fitting, and about four different graduated sizes of pvc, cemented together. Then I could screw it onto the end of pistol type hose sprayer, stick the end in the radiator hose, and spray away. It also fit the heater hoses. So I’d give it a jolt of spray for a few seconds and let it drain and repeat. Then reverse the flow. Worked pretty good. I actually copied it from a similar device a radiator guy used except he used air pressure and water.

Only works for cleaning out the loose stuff though and that blue stuff may stuck too hard.

I don’t think you can dislodge something that is designed to seal head gaskets with water from a hose.
Now that you have tried Blue Devil , I think your choices are a different engine, radiator and heater core or seeing what a wrecking yard will give you.