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I have an old rusted through exhaust shield (covering the manifold) that I am replacing with a better looking and better condition one from a local junkyard. This one is real nice with minimum rust but I am painting it to hopefully protect it from future rust. I'm using duplicolor engine enamel paint (up to 500 degrees) but had to use the rust fix primer and that is only safe for up to 200 degrees.

I used a temp probe on the existing shield at idle and it leveled out at 117 degrees, but does anyone know how hot it gets actually driving? I don't want the primer having ill effects. And i like the heat shield being there I don't want to nix it altogether. Thanks!

 
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The exhaust manifold temp varies a lot. It can get hot enough to glow red. How hot do you think that would be?

The heat shields are only spaced about 1/4 inch away (or less) from the manifold (and cat?) in many areas.

117*F ? It will get a whole lot hotter than that. Well beyond the 200 rating of the primer. I'd expect higher than the 500 under some conditions ........ I guess you will find out if the paint will survive.



No, I have never measured it myself.
I'll guess maybe 10% below the temp of the manifold when the air movement is minimal.