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Radiator flush this weekend


Kevin McGrade

Hi everybody, I was going to attempt a radiator flush and coolant change this weekend and was looking for all the info I can gather before starting. Oh and I have a 92 with the LT1 of course.

Is there somebody that has a step by step procedure? I have done basic things but I am not no mechanic by any means.

Thank you guy and gals
When I flush my cooling system I follow this procedure:
Open the radiator drain, catch the antifreeze for recycling if needed.
Then I remove the radiator cap and put a garden hose in the filler neck with just enough water flowing to keep the radiator level up as the drain is draining.
Once youv'e got the flow right startup the engine (make sure you keep the water level up) and let it run until you see only clear liquid coming from the drain, shut the drain, the flushing is done.
Shut off the engine, let it cool down and then open the drain again and let as much water drain out as possible. Shut the drain again for the final time, I know this leaves some clean water in the system but what I do at this point is fill the system up with straight anti-freeze and start the engine again, heater on high and let it run, keeping an eye on the radiator level. keep topping off with straight anti freeze until the level stabilizes. Usually when Im done adding the straight anti-freeze to the clean water that remains in the system I end up with abvout a 50/50 mix when checked with an antifreeze tester.
I've been using this procedure for more than 30 years now on numerous vehicles i've owned and never had a problem.
You can get more involved and remove the drain plugs on the block etc, but if you follow regular suggested maintenance intervals for your cooling sysetm you shouldn't build up that much sediment in the cooling system.
I switched my vette over to the extended life anti-freeze, the orange stuff, and you can go up to 5 years before flushing. Only thing is that the extended life antifreeze will leak from places the green antifreeze wouldn't, a little tightening up on the hose clamps will take care of that problem though.
Thanks for all that info i will go for it tomorrow morning. One more question is how much fluid does the lt1 hold?
The manual states 17.8 quarts but that seems a lot to me
I have an L98, but it's basically the same engine block, I use about 6 to 7 quarts of straight antifreeze when I flush. Yours may vary depending on radiator volume and heater core volume etc.
Great!! thank you for all the info.. I just picked up 3 gallons of distilled water and two gallons of prestone.

Bright and early can't come quick enough
Let me know how it goes, the distilled water is a good idea, but I must admit I've never used it. I forgot to mention that I usually add a bottle of prestone water pump lube to the mix, you can add it later if you don't have it on hand.
I hope you have the same weather there today that we have here in MA, it's a picture perfect day to work outside, there isn't a cloud inthe sky and the temp is around 65 deg. My kind of day. I just finished giving my Vette a final detailing for a show tomorrow.
Oh-------------I see you are from the great state of Massachusetts, you actually live just a few miles north of me. Are you going to the Dust Off show in Burlington tomorrow?
Hmmm... didn't now about that show, I will look into it and maybe I will head down there tomorrow. Nancy and I were thinking of taking a drive up to the busweiser factory.

Everything went well with the coolant change and after flushing the engine I never got more than a gallon of distilled in there.
I would say I am running about 40% regular water 40% prestone and 20% distilled.
I also through ina bottle of water wetter!!!

Save the wave
Kevin McGrade said:

Bright and early can't come quick enough

MAN, that is SICK! :puke

can't remember the last time I said THAT! :(

"Dexcool" is good stuff, the extended life anti-freeze.
fastglass95 said:

MAN, that is SICK! :puke

can't remember the last time I said THAT! :(

"Dexcool" is good stuff, the extended life anti-freeze.

Dude I was talking about bright and early sat morning:eyerole

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