Combat Vehicle Air-Cooled Engines. On combat vehicle air-cooled engines, ferrous metal parts are painted with
olive-drab, rust-inhibiting enamel, TT-E-485. Aluminum portions, including the cylinder fins, are left unpainted. The base
of the cylinders is coated with waterproofing, electrical, ignition varnish, MIL-V-13811.
Engine Compartments. All exterior surfaces of combat vehicle engine compartments not exposed to outside view
shall be painted white or light green for better reflection of light.
Radiators on Liquid-Cooled Engines. When radiators are stripped to bare metal, an external coat of radiator paint,
NSN 8010-00-728-8228, should be applied to outside of tanks and core after they have been assembled. Ensure paint
does not restrict air flow through core elements, since clogged core elements will not dissipate heat.
3-17. TAPE TEST (PAINT ADHESION TEST) FOR ALL FINISHES
(See figure 3-1.) Test paint adhesion on coated surfaces. Do not use test panels instead of actual production units. Test
the surface after the paint finish has cured on an out of the way place acceptable to quality assurance representatives as
Make a V-shaped scratch through the paint finish with a sharp metal blade. Make the scratch approximately two
(2) inches long and one half (1/2) inch between edges at the widest point.
Press a piece of pressure sensitive tape (3M code no. 250 or equivalent) firmly over the V, in the direction
indicated on figure 3-1. Press out air pockets.
Wait at least ten seconds, then quickly pull the tape away, in the direction indicated in figure 3-1.
Interpret test results as follows:
If no paint comes off of the taped area, the coating is acceptable. (Removal of overspray (para 4-13a) is not
a test failure.)
If the topcoat, primer or pretreatment comes off with the tape, then the coating has failed the test and must
be removed and another coating applied and tested.
After test is passed, repair the scratched area by feathering-in with appropriate pretreatment, primer and