another radiator question

ModAfan

Senior Member
Any suggestions on how best to clean a radiator that is out of the car? My engine is being rebuilt and I’d like to clean the radiator before it goes back into the car.
Thanks.
 
i just flushed mine with water and also put air through it using the compressor to create bubbles /turbulence. Simple and cheap, but maybe not the best - Lots of chemicals solutions for sale claiming to do the job effectively.
 
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Off the car I use draino (lye) for about 20 minutes. Back flush well with water and compressed air
 
having just done this, its generally goopy gunk that is in them. I tried the draino method with OK results, i let it sit overnight with concentrated degreasing stuff in it and that had globs if grease come out of the radiator.

You really need a setup with a sump pump or pool pump or something that moves great quantities of water quickly to backflush it. your garden hose wont be adequate.
 
Radiator's out? That's why God gave us radiator shops. Drop it off and have it boiled out!
 
I just got a radiator back from the shop. I'm putting a new engine in the roadster and wanted to make certain the 25 year old radiator was clean. The shop boiled it out and pressure tested it and soldered up a few things and charged me $47.50 which was acceptable to me. Now I don't have to be concerned about it and guess about it's condition.
 
and charged me $47.50...............

in NJ that is completely impossible.
WOW- no sham wow!
 
I have used the radiator shop method in the past but they are getting harder to find. Maybe the cause for globs of gunk in a radiator has to do with those who have original style water pumps. There's a tendency to over grease the water pump which causes grease to accumulate over time in the cooling system. Distilled water, antifreeze and water pump lubricant seem to be a good mixture to use once the radiator is clean.
 
The secret is to have a shop in your area that knows when a boil out will do or a rod out is needed to make sure the job is done per what the radiator needs. Many radiator shops are not touching brass radiators, and then they have to have that know their stuff.
 
having just done this, its generally goopy gunk that is in them. I tried the draino method with OK results, i let it sit overnight with concentrated degreasing stuff in it and that had globs if grease come out of the radiator.

You really need a setup with a sump pump or pool pump or something that moves great quantities of water quickly to backflush it. your garden hose wont be adequate.

I use short light bursts of air with water. The air helps a lot
 
ModelAfan,
After driving it a few months, be SURE to back flush it! Rust flakes seem to just come out of the BLUE!
Bill Gurgle
 
If it really has plugged tubes, then rodding is about the only way to clear them, but that should be determined first, and only done by someone experienced at it. My Model A had over 20 tubes totally plugged and they were able to open all but a few; this was after the original owner had it boiled out, which did not really work.
 
To do it right, You have to boil it out (softens rust), then you remove top tank and "rod out" the core. You cannot force rod down tubes as they will split. That is why you boil them out first. Some times we would have to put radiator back in boil out tank to soak two or three time. Too bad EPA closed most of us down................
 
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