Peterbilt 357/378 Fuel Tanks

Frequently Asked Questions About Peterbilt 357/378 Fuel Tanks

What size fuel tanks fit my Peterbilt 357 or 378, and how do I determine capacity?

Peterbilt 357 and 378 models typically accommodate fuel tanks ranging from 50 to 150 gallons, with 100-gallon and 120-gallon tanks being the most common. To determine the right capacity, measure the distance between your frame rails and the available mounting space. Standard diameters are 23 inches or 25 inches. Most 357/378 models from 1987-2007 use 25-inch diameter tanks, but always verify your specific truck's configuration. Check your door jamb sticker or original equipment specs for factory tank size information.

Are these fuel tanks compatible with both Peterbilt 357 and 378 models across all years?

While the 357 and 378 share many components, fuel tank compatibility varies by year and configuration. Tanks manufactured for 1987-2000 models generally fit both 357 and 378 trucks with the same wheelbase. However, 2001-2007 models may have different strap spacing or mounting brackets. Extended hood 378 models sometimes require different tank lengths than standard 357s. Always verify your truck's year, model, and frame rail spacing before ordering. Most aftermarket tanks are designed to fit multiple years but may require minor bracket adjustments.

What's the difference between aluminum and steel fuel tanks, and which should I choose?

Aluminum tanks are 65% lighter than steel, resist corrosion better, and are ideal for weight-sensitive applications. They typically cost 20-30% more but last longer in harsh conditions. Steel tanks are more affordable, highly durable against impacts, and easier to repair if damaged. For trucks operating in northern climates with road salt, aluminum is recommended. Steel tanks work well for local operations where weight isn't critical. Both materials meet DOT requirements when properly manufactured. Consider polished aluminum for a show truck appearance or painted steel for a factory-match look.

Can I install these fuel tanks myself, or do I need professional installation?

Fuel tank installation requires intermediate mechanical skills and proper safety equipment. You'll need tank straps, mounting brackets, fuel line fittings. The process typically takes 3-4 hours per tank. Key challenges include safely draining existing fuel, aligning heavy tanks (empty aluminum tanks weigh 40-50 lbs, steel 80-100 lbs), and ensuring proper venting. Many drivers successfully install their own tanks, but professional installation is recommended if you're uncomfortable working with fuel systems. Always disconnect batteries and work in a well-ventilated area away from ignition sources.

How do I match the finish to my existing tank or achieve a specific look?

Fuel tanks come in several finishes to match your truck's appearance. Polished aluminum provides a mirror-like chrome appearance without the weight. Brushed aluminum offers a satin finish that hides minor scratches. Painted steel tanks can be ordered in black, white, or custom colors to match your cab. For dual tank setups, ensure both tanks have identical finishes for a uniform look. If replacing one tank, note that new polished aluminum won't perfectly match weathered tanks - consider polishing your existing tank or replacing both. Most painted tanks use industrial enamel that matches Peterbilt factory colors.