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While planning some tasks for "restoring" my engine bay, I noticed one of the things that significantly affect the way it looks is the heat shield. It's rusty, since the corrosion was probably much more accelerated by the heat it's insulating.

Engine's Heat Sink

My idea was to remove the heat shield, remove the exhaust manifold, clean the rust on both with a steel brush (being careful not to touch the side that makes contact with the cylinder head), clear carbon deposits with a decarbonizer on the exhaust manifold, paint both with black high temperature spray paint and reassembly them with new screws (there's even one missing) and a new gasket.

The first doubt is whether painting the heat shield black (or any other color) could affect its function. The second doubt is if the temperatures usually get over 600ºC in those parts, and if so, do you think a 1000ºC paint would cover the temperature range?

The engine is a GM 1.0 MPFI 8V.

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    I don’t think it would affect its function if you applied the paint on the outside of the shield, and high temp paint should do the trick (even on the inside of the shield it wouldn’t inhibit the ability of the shield to actually keep in the heat)
    – sjfklsdafjks
    Nov 29, 2018 at 17:59
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    I cleaned and smoothed the headers (exhaust manifolds) on my v8 years ago - took a good few hours along with spraying yhem with high temperature paint. Looked great untill the first hard run up the motorway... then all the paint had gone... Won’t do that again...
    – Solar Mike
    Nov 29, 2018 at 18:39
  • @SolarMike you remember the temperature limit of the paint you used? I've seem some ranging from 600ºC (1112ºF) to 1093ºC (2000ºF), though the prices increased almost as fast as the temperature lol
    – IanC
    Nov 29, 2018 at 18:55
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    @IanC no, was too many years ago - was advertised as paint for exhaust manifolds though...
    – Solar Mike
    Nov 29, 2018 at 19:25
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    Use anti-seize when reinstalling the bolts
    – Martin
    Nov 30, 2018 at 8:27

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There are special paints that will withstand temps of 2000 degrees. The problem is to get this type of high temp performance you have to be meticulous in your parts prep. Look for a paint labeled exhaust manifold or header paint. Pay attention to the preparation and curing instructions. I haven't found a type that lasts more than a year before it needs to be reapplied.

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