Even when protected by the hood, an old pickup truck’s engine will start to show the effects of dirt, moisture, and age. Here’s how to achieve a well-weathered but functional appearance for your next work-truck scale model. But first up, a list of some of the paints you’ll need:

• Black primer (such as Ammo of Mig Jimenez Titans Hobby; No. TTH100)
• Tamiya Hull Red (No. XF-9), Red Brown (No. XF-64), Semigloss Clear (No. X-35)
• AK Interactive Xtreme Metal Dark Aluminum (No. AK480); Worn Effects chipping fluid (No. AK088)
• Black, burnt sienna, raw umber, and yellow artist oils

Prime the engine and transmission and mist a coat of hull red over the engine only. Follow up with washes of Tamiya Red Brown and burnt sienna oil paint.

Moisten the surface of the engine with water and sprinkle salt over the part. Let the salt crystals dry in place, then airbrush chipping fluid over the engine.

Let the fluid dry for 10 minutes and paint the engine an appropriately colored acrylic. In this case, a custom-mixed blue. After the paint dries, use water and a toothbrush to scrape away the salt and activate the chipping fluid for naturally worn-looking paint.

Mask the engine and airbrush the transmission an accurate color for the topic you are modeling — dark aluminum, in this case. Remove the masking and coat the assembly with semigloss clear to protect it from the washes to come.

Adding black and burnt sienna artist-oil washes on the engine simulates oil, grime, and further rusting. An orangish mix of cadmium yellow and burnt sienna imitates light rust that accumulates in recesses on top of the engine. Raw umber artist oils make bare-metal parts, like the pulleys and transmission, appear dirty and oily.

Not everything on the engine would be rusty, and you’ll want to create some visual interest. Highlight bolts, linkages, and other parts that you want to stand out with a silver marker or paint.

Hose clamps can be easily made by coloring paper with either a silver marker or paint and cutting it into strips.

You can buy aftermarket hoses or make your own from wire of suitable scale diameter. Use white glue to attach the paper clamp to the ends before gluing the hose in place on your engine.

Like making clamps, you paint paper with dark gray or black acrylic paint and slice a strip off to use as a fan belt.

Lace the paper fan belt through the pulleys and affix it with white glue. Again, you can purchase aftermarket ignition cables, use wire of the proper scale diameter for your engine, or even make your own from stretched sprue, as shown here. Your completed engine is now ready to install in your model pickup truck.