Painting a radiator? -
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post #1 of 13 Old 06-01-2013, 12:11 AM Thread Starter
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Painting a radiator?

I am thinking about painting my radiator red on my black LJ. There is just something about the bare aluminum that I don't like. I have read up on the heat transference and as long as you use the correct paint it should not be a problem. I am just wondering if anyone has done this, or something similar to their Jeep before, and please provide pictures if you have.

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post #2 of 13 Old 06-01-2013, 04:27 AM
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Not to sound like a smart *** but why not just get some grill inserts?
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post #3 of 13 Old 06-01-2013, 08:39 AM
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Paint, any paint, will act as an insulator, the radiator will not work as well. More than likely it will be fine but if its on the edge of not working well enough it may tip over the edge. Id just rattle can it if it was me.

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post #4 of 13 Old 06-01-2013, 06:22 PM
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Ive painted dozens black so red should not be a problem. From rattle can to automotive paint. I did it for looks and to protect the brass.


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post #5 of 13 Old 06-03-2013, 02:37 AM
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Yes, radiators can be painted with black or any color, and the cooling system won't be affected. My friend works in a repair shop and they can paint them.
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post #6 of 13 Old 06-10-2013, 02:47 PM
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Do not paint or otherwise coat your radiator fins with anything. It's simple heat transfer and material properties - metal is more conductive than the compounds that make up paint therefore you will reduce the cooling capacity of your radiator. It may not be catastrophic, it could just cause your fan to run more or your thermostat to open sooner.... But in the right conditions it could also be the end of your engine. Why risk it?
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post #7 of 13 Old 06-12-2013, 08:58 PM
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Posts: 1,180 they sell that, but I just used a light mist from cheapo black rattle cans, and it worked fine & looked great.
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post #8 of 13 Old 06-14-2013, 06:40 AM
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Well every radiator I have ever seen with the exception of the Aluminum ones are painted Black, and I assume they are not as they generally look good. That said if you want to paint them you should be OK.

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post #9 of 13 Old 06-14-2013, 06:51 AM
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Originally Posted by Jims-87YJ View Post
Well every radiator I have ever seen...... are painted Black,
Do your research. I've read somewhere there is a Thermo-chemical reason for this fact.... and may even be specialized paint.
How cautious I'd be would depend on how hot it gets where I live, I guess.
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post #10 of 13 Old 06-20-2013, 08:38 PM
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Thin coat of paint on your radiator shouldn't affect its cooling capacity noticeably. Yes, paint is an insulator. However, it's not so effective an insulator as to severely impact the efficiency of most modern radiators. Bigger concerns than the paint on the radiator fins include bent fins, bugs in the fins, antifreeze-water ratio, air density, thermostat temperature, and a number of other factors. I have a lawnmower engine that's obviously air cooled and it runs just as well with a coat of paint, than it did before I cleaned it up and painted it. The same principle applies.

While it's not something I'd do, myself, just out of preference, it's not something I would expect to impact performance in any noticeable way. Just don't use a thick, high-temperature enamel like a brake paint. Krylon should suffice.

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post #11 of 13 Old 06-30-2013, 09:18 PM
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Well I'm not an expert in radiators per say but I do have extensive knowledge of condensing coils on air conditioning systems and i know that the funcionality of the two is exactly the same. Air moving across the tubes and fins dissipate the heat from the cooling this case anti-freeze. Coating a coil/radiator on anything will diminish it's ability to dissipate the heat. In the case of the condesnsing coil the heat builds up and with the pressure which causes the compressor (comparable to your engine) to run hotter and hotter. Some do come black from the factory but that is not paint, it is a special epoxy coating. Factor in that spray paint contains plastics and this just has bad idea written all over it.
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post #12 of 13 Old 07-01-2013, 12:53 AM
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Polyepoxide and polyester alkyd resins are similar enough in how they act with regard to heat. Polyepoxide coatings, in fact, contain more "plastics" than the typical enamel spray paint, not that the presence of polymers is a bad thing. Bear in mind that your radiator temperature doesn't exceed 210 degrees under normal operations, which is far below the point at which any plastic resins in any given paint break down once cured.

Yes, you will theoretically diminish your capacity for heat transfer, by introducing a surface coating with a mild thermal insulation, but the observable results under normal conditions should be minimal if they exist at all. At most, a very small amount of the radiator's actual surface area will actually be covered, mostly along the least-relevant forward face, which makes up a tiny fraction of the actual surface area of the fins. Bear in mind you can't get paint into every nook and cranny and will likely be satisfied by just seeing the front face painted. A small amount of paint will land on the inner area of the fins, but this is a negligible amount, applied to the largest and most important part of the cooling surface.

It's my opinion that painting your radiator will have no effect on the performance, reliability, or safety of your vehicle.

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post #13 of 13 Old 07-01-2013, 11:16 AM
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Like was already said..common sense says that any coating will insulate and hinder thermal heat removal..unless its a coating designed for radiators.

I've been there and done that on a radiator after a guy told me a few theories that it shouldn't effect it in an old 1972 bronco and it DID make a difference when cruising the slow trails...

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