Radiator is being rodded out

A

AlanD

Senior Member
As with many, I'm having boil-over issues with my '30 coupe. After several Prestone Superflushes the water still comes out like dark apple cider, so I just brought the radiator ( I bought this one new approximately 5 or 6 years ago) in to have it rodded out.

Well, the shop just called and said it's ready to go, but was plugged up pretty bad. They said I should thoroughly flush the block out before putting the radiator back or it will get plugged up again. And then they said to refill it with mostly straight antifreeze. I told them I had been running only distilled water and a rust inhibitor in it because water cools better and doesn't etch the paint when it comes out. They didn't like that idea.

So Now I'm wondering what to flush the block with? I've read about vinegar on here recently. What is the best option?
Thanks everyone.

Alan in Louisiana
 
stretch a panty-hoe over the outlet coming out of the head before you put your hose on. This will catch debris before they go in to the radiator. After some time, take the hose off and take off panty-hoe. You'll be surprised at how much it catches.
 
get a jet nozzle with a long long copper tube on it,hook to compressor with #100 pressure, stick the copper tube and a water hose in the top radiator hose with the radiator out, plug the hose around the air nozzle and water hose with rags to make a tight seal, turn water hose on full blast and trigger the jet nozzle with short blasts of air to creat turbulence in the engine water passages, any loose rust or sand or whatever will be washed out the bottom radiator hose
 
All good advice above. My question would be what was it plugged with, and what is left inside of the water passages? If it is something 'organic' (grease, slime, etc.), the Vinegar will do the trick. If it is rust scale, it will take Phosphoric Acid to do any good. Vinegar will not dissolve rust and Phosphoric will not touch grease/etc.

I would not flow this acid through the radiator though. I would plug the side port on the block and fill through the upper water neck in about a 25% solution of the acid (available at Home Improvement stores in the paint section) with the water. Start the engine with the fan belt off and allow the engine to reach a temperature of approximately 150° and then shut it down and let it cook. Heating the acid will increase its effectiveness. You might repeat this starting process in about an hour, ...and do this 4 or 5 more times. Then drain the block into a pan to save the solution followed by flushing the inside of the block & head with pressure from your garden hose. Rinse until it is flowing clear water. Strain your acid solution through a towel to remove the sediment and junk that flowed out when you drained it, then plug the side of the block again and refill with your solution. Repeat the warming process again by starting it every hour a couple of times and then let it set overnight. Drain and flush with a high pressure nozzle on a garden hose. Generally speaking, this will dislodge any rust scale & particles from inside the water passages and you should be able to get good heat dissipation from the block into the coolant.

One thing that I might warn you of, it has been my experience that sometime radiators that have age on the have the fins deteriorated where they have fractured from the tube. This creates a problem in that they cannot properly dissipate the heat. The radiator will pass a flow test and show clean, but again it just cannot transfer the heat.
 
I have one of these Gano Filters in my Mercury Comet and it has done wonders for keeping the cooling system free of debris and functioning properly. I used the aluminium version so it's not see-through but I didnt trust a plastic tube in my cooling system (plus the plastic one is ugly). When/if the car starts getting warmer just clean the filter then flush and fill like you normally would.
 
if you lived anywhere near PA id say bring it to my shop and we'd shoot the "Zoo" pressurizer through it.
 
Look up Gano Auto Coolant Filter Company on the internet. They make a great filter system that prevents any junk in your engine from getting into your radiator. I highly recomend their simple system any time you install a new engine that's been hot tanked
 
That's interesting about the Gano Filter. I had not heard of it before and I'm surprised that none of the Model A parts suppliers carry this or something like it. After some further digging, I saw some home made versions of this idea.
In fact the radiator shop owner suggested I get some copper or brass mesh and put it over the neck before putting the hose on.

I'm going to get some phosphoric acid and work on this over the weekend.
 

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Well I got some and now I remember this phosphoric acid, I've used this stuff before but didn't know it was phosphoric acid. I used to paint it on rust and let it chemically react, with a really bad smell. I don't mean to question advice here but I'm a little concerned about putting this in the block. What if it eats way some little nook inside and ruins the engine? This motor has been good for 20 years (except for some boil overs, ha!).

From this forum I read that the radiator by itself holds 1.5 gallons, and should empty in about 4 seconds. Before having my radiator rodded out, it took about 9 to 10 seconds to empty.
I'm glad I made this measurement because I can really see the difference. After being rodded out it, it takes about 4 seconds to empty - as you can see in the video clip i made below.
radDrain.gif

It's interesting that it seems to hold nearly the same amount. I'm thinking that the capacity might not change much with plugged rods but the flow rate obviously does.
 
I've used Oxalic Acid (wood bleach) to flush the cooling system on my Mercury Comet before and it did a terrific job. The stuff is harmless to metal, only attacks the rust. It comes in a crystal form. I mixed it with hot water, poured it into the radiator, filled the rest of the cooling system and drove it like that for a week. Then I flushed it with water and some baking soda, installed a Gano Filter and have been trouble free since.
 
Re: Radiator is being rodded out - update

I keep updating this thread to help others with the same problems. I know I have gotten a lot of good information from old threads as well as this one.

I have been running some tests with a rusty bolt sitting in a very diluted mixture of phosphoric acid and water. When I looked at it yesterday before church I didn't see much change, but this morning (48 hours later) I can see the rust is flaking off - see below.

On a side note, I was kinda surprised at how fast the block heats up. I started the engine to warm up the flush mixture - as advised above. It only took 30 seconds to a minute to get the block up to 120 degrees at just an idle.
 

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Speaking of the Gano filter, I made my own version out of some brass screen. The only problem was that I could not get the hose to seal. Originally I had a lip that wrapped around the outside of the hose and clamp all that down - as seen in the pic below. To try to stop the leaks, I cut all the lip off but even that resulted in a leaks. After many attempts and combinations I have scrapped the idea until I can figure out a better way to fit it in there and seal.
Any ideas?
 

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Phosphoric acid only eats or etches Iron Oxide (rust), not raw iron by itself. So you are good to mix it with water and run the engine like Brent said. Just flush it when your done.
 
Will the acid damage any of the painted surfaces of the car? I was going to get a long piece of flex hose, attach it to the lower inlet, and keep the end high then bring it down to drain.
 
I was very careful to not spill the phosphoric acid and water mixture so I don't know how it would react with painted areas. It didn't seem to mess with the rubber hoses, but it will dissolve concrete. A few drops came out of the brass drain valve and left a foamy divot on the floor.
I used a very dilute concentration and let it sit in the block 24 hours. Maybe I should have left it in longer but the suspense was killing me.
 
Ed, here is what I did to attach a water hose to the lower side inlet on the motor, for my purposes I just let the water flow out the water pump hole. All those pieces are readily available at your local hardware store. Of course I wasn't worried about paint at the time.
 

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I went out this a.m. and got a 1" PVC ball valve and it fit nice inside the radiator hose I had.No one had the acid, I finally called a friend who owns a paint store and he had some that was a 55% solution and the directions said to mix with water 3 to 1. I started the process about an hour ago and will go down to the barn and start the engine again in a few minutes. Another question I should have asked before, will the acid do anything to my copper gasket? Thanks
 
Look up Gano Coolant Filters on the net. A Gano filter will filter out all the junk in your cooling system and not allow it to go back down into the block. It's the best way to keep your radiator from getting cloged.
 
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