I have my '59 radiator off and was wondering what to use to clean it internally?
I checked the auto stores and all they sell is a hot clean with the unit on the truck. I would like to circulate something through it before I do the final preservation to the exterior.

 

You can block off the hose outlets, put CLR in it and let it soak a day or two. Then flush it good with a garden hose.

CLR Calcium Lime & Rust Remover - Walmart.com

 

I started to purchase that product but it warns not to use on copper or brass.
Do you still recommend the product? They may have been concerned with use on exposed sink fixtures.

 

get a short piece of heater hose that runs from intake to water pump, install a tee garden hose flush. Prestone makes it in a kit for about 5.00. This reverse flushes the radiator out the top. Can run engine with garden hose on just enough for the water to flow out the top of the open radiator via the plastic output spout.

 

Take it to a radiator shop and have them dunk it for you.
Once cleaned it will be pressure tested, any leaks will be repaired then painted.

 

a good radiator shop will remove the tanks and rod out the core if it's salvageable. Don't be surprised if the core needs replacing. Most home remedies only cause more problems by loosening up crap that will end up in the tubes..

 

I guess I never read that. Maybe the radiator shop guys are right.

 

I would echo what others say, take it to a radiator shop and have it done professionally, thats what I did. Whenever using fluids on these old trucks you have to be careful, because a lot of the newer stuff is not compatible due to the metals used in the old days.

 

Thanks for all the suggestions. I flushed it with a vinegar solution and small pump. Cleaned the fins and rinsed with fresh water. It will probably be next summer before the truck will be ready to start.