What kind of paint goes on a radiator?

[Mex-Busnut]

I took my radiator out and down to a friend's shop. He took off one of the tanks, and showed me. Pretty rotten. A whole bunch of patched places on a whole bunch of tubes. So I had to order a new core. He also had to rebuild the metal overflow tank, which had a busted pipe elbow coming out of it, and showed signs of several previous patches. He also replaced one of the two tanks, which was in a real mess. Anyway, it is all back together, and tested. By the way, I have used this guy for over 20 years and never had a problem with any radiator he has reppaired for me.

But down here South of the Border, I have never had a radiator shop paint a radiator. Why? I have no idea. What kind of paint can I use, that won't hurt cooling? I am assuming paint on the outside (and proper antifreeze on the inside) would help ward off corrosion?

Thanks in advance!

[artvonne]

  Paint will prevent corrosion, black paint will radiate heat a lot better than any other color, and flat black paint more so than gloss or satin. But how to get it inside there on all the interior tubes? I think they would have to be dunked.

[Sean]

Is the new core aluminum or brass?

If it's aluminum, you should leave it unpainted for the best heat transfer.

if it's brass, it needs to be painted to prevent corrosion.  As Paul suggests, flat black is the best color to radiate the heat.  There is actually a special black paint called "radiator paint" that is really the right product for the purpose, but I'm afraid I can't tell you where to find it there.

There are also special paint spray guns that radiator professionals use to get the right spray pattern with the special low-solids paint.  I'm surprised the radiator shop does not have this equipment?

The trick is getting it everywhere it needs to be without also plugging up the openings.  Not something I would try myself with a rattle can, even if it was available, but painting is not my strong suit.

-Sean
http://OurOdyssey.BlogSpot.com

[luvrbus]

 



www.eastwood.com is where I buy my radiator paint Napa or others will have it also regular spray enamel is to thick,I may have a can I'll check Sun for you Eastwood sells it by the case you don't need 12 cans

[Mex-Busnut]

Thanks to all for your input.

There is no O'Reileys or Napa down here. The only American chain is Auto Zone. I guess I will check there.

It is deffinitely NOT aluminum. I believe it is brass, from the color.

[JohnEd]

Road spray is bad stuff...especially in a city.  I am told by rad shops that you should wash the rad with mild soap and soft water as often as the conditions in your area dictate.

Definitely "What Art said" and that includes taking Clifford up on his generous offer of sending you some after you cover costs.  I have always used flat black lacquer in a rattle can and applied a thin coat but then I didn't know they made a special paint till this post. 

Good luck with Auto Zone....They should be able to get it for you.  I will call them local tomorrow and see if they have a stock number in case your shop comes up empty.

John

[bevans6]

Ii'm not positive of my climatology, but I believe where you are you don't get a lot of road salt.  That would make an unpainted brass radiator core last quite well.  Unpainted does cool better.  We stripped the paint off the brass radiator in a race Mini Cooper S and got a useful increase in cooling ( but it was on the edge of capacity so a little increase meant a lot) and the owner got a nice piece of brass to polish in the engine bay...

The light coat of flat black low-solids paint is the best idea.

Brian

[boxcarOkie]

Rustoleum, flat black or glossy.  Pick it up just about anywhere.

BCO

[junkman42]

When I was In high school I worked in a radiator shop!  If I remember correctly We painted radiators with a asphalt paint.  The old retired army captain from WW1 did not waste money on any thing!  John L

[luvrbus]

Radiator paint is a asphalt base paint fwiw I just read the can that has no repellant in it lol

good luck

[Just Dallas]

Try using BBQ grill paint from your favorite merchandiser. It costs about $5/can USD and will last about 5 years if applied to a clean surface.

Good Luck!

DF

[TedsBUSted]

When I was In high school I worked in a radiator shop!  If I remember correctly We painted radiators with a asphalt paint.  The old retired army captain from WW1 did not waste money on any thing!  John L

I think I worked there too. But I though that years of lead exposure and the depression had made the  old Dough-Boy tough and thrifty, not the war.  

The first time I opened a can of undiluted radiator paint and saw its very thick consistency, and smelled the "asphalt" I thought it was either cured or had been mixed up with roofing tar. That's how thick it was too. We'd dilute it heavily with turpentine, or even gasoline, and spray it with sort of a crude siphon "spatter paint" air gun. It NEVER cured  

I guess the paint is, or at least was, "lamp black" based. Any other coating supposedly greatly inhibits heat dissipation. I always wondered about it, mostly because I hated working with the "gooey" never-dry stuff.  

Although I've never read a good authoritative word on it, I believe it's correct that the lamp black had great heat dissipation qualities whereas common paints will insulate. But then again, some OE radiators were finished in what seems like common enamel that dried well, so I'm not sure. Maybe the "tar" was a holdover from the old days and was favored because it would flow well to cover deep in the core and was easy to strip for future repairs? Or maybe the "asphalt" was favored because with heat and cold cycles it doesn't bake and then crack-and-peel like common paint? Or maybe because it doesn't "bridge" tiny gaps in core "fin" material?

Anyway, "real" radiator paint seems to have enough merit that I guess I'd avoid spraying common paint on a radiator core. Especially so if a system doesn't have a surplus of cooling capacity to begin with.

Ted

[gus]

For over 60 years I've never used anything but regular ole flat black spray can paint or radiators.

Sometimes I paint the top tank with gloss black, depends on the vehicle.

I don't usually paint the fins except for maybe a light dusting.

Never had any problems.

[TedsBUSted]

Right Gus, I've seen lots of that too.
I don't suppose that painted tanks are much of an issue at all, and as I wrote, it appears that some OE radiators were painted with common enamel.

Mostly what I was trying to point out is that if a cooling system already seems marginal, there's no sense "insulating" the core by using the wrong paint.

Ted

[gus]

Ted,

Can't disagree with that.