Paint types
Under-bonnet paint is several products sharing one shelf. A block sits at about a hundred degrees and wants a hard enamel. A manifold runs at several hundred and wants a coating that only finishes curing once it gets hot. Put the wrong one on and the engine looks tired by the end of its first summer.
Three questions sort it out. How hot does the part get? What is going to be spilt on it? And what kit do you own? The table answers the first two. The third matters more than people expect, because the toughest paint here is also the one that needs breathing apparatus.
| Type | Use it on | Makers rate it to | How it cures | What you need |
|---|---|---|---|---|
| Engine enamel | Blocks, heads, rocker covers, sumps, brackets | 140°C to 300°C, depending on the tin | Air dries, then hardens with heat from the engine or an oven | Ventilation and a vapour mask |
| Very high temperature coating | Manifolds, downpipes, exhausts | About 650°C to 1,090°C | Staged heat cure, on the car or in an oven. It stays soft until you do it | Ventilation and a vapour mask, plus the patience to run the cure |
| 2K two-pack | Anything that meets petrol, brake fluid or regular degreasing | Varies by product. Read the sheet | Chemically, once the hardener is mixed in. Hours in a tin, days in an aerosol | Air-fed breathing apparatus and extraction. HSE says a filter mask is not enough |
| Primer | Bare aluminium, or wherever your topcoat's maker tells you to | 80°C for bodyshop etch primer. 288°C for VHT's engine primer | Air dries | Whatever the topcoat needs |
| Clear lacquer | Metallics with a matched clear, and bare brackets | 80°C for ordinary lacquer. 288°C for VHT's engine clear | Air dries | Whatever the colour coat needs |
| Wrinkle finish | Rocker covers, air cleaners, dash panels | 177°C | Air dries. Warmth helps the texture form | Ventilation and a vapour mask |
The ratings are the makers' own and they are not comparable like for like. Some are peaks the film survives for a moment and some are temperatures it will live at. Each page below says which is which.
Browse every paint in the shop, or go straight to engine enamels, very high temperature coatings or 2K two-packs.
- Engine enamel
One-pack heat-resistant enamel for blocks, heads and covers: what it survives, where it fails, and how long before you can start the engine.
- Very high temperature coatings for manifolds and exhausts
Silicone and ceramic coatings for manifolds, downpipes and exhausts: what the ratings mean, why the heat cure is not optional, and when to send the part away.
- Primers for engine paint
When engine paint needs a primer, when the maker forbids one, and why a bodyshop primer is the weak layer on a hot part.
- Clear coats over engine paint
Why ordinary clear lacquer doesn't belong on an engine, the three cases where a clear is the right call, and the one clear that is rated for the heat.
- Two-pack (2K) paint under the bonnet
What 2K paint is, why the trade uses it on engines, what a 2K aerosol changes, and what HSE says you need before you spray it.