Peterbilt 357/378 Engine & Performance Parts

Frequently Asked Questions About Peterbilt 357/378 Engine & Performance Parts

Will these engine and performance parts fit my specific Peterbilt 357 or 378 model year?

Fitment can vary based on the engine platform installed in your truck (such as Cummins, Caterpillar, or PACCAR options used across different production years), as well as the specific model year and configuration of your 357 or 378. Before ordering, check the product listing for stated year ranges and engine compatibility, and compare that information to your truck's engine model and VIN details. If you are unsure, reaching out to our parts team with your engine serial number and truck specs is the fastest way to confirm a proper fit.

What types of components are included in this category?

This category covers parts related to engine operation and performance, including components such as air intake and filtration parts, exhaust and emissions-related hardware, cooling system parts, belts, sensors, gaskets, and other engine accessories used to maintain or improve how your Peterbilt's engine runs. Not every part listed will apply to every engine option, so review each product description carefully.

Are these parts OEM or aftermarket, and does that affect quality?

You will find a mix of OEM and quality aftermarket options within this category. OEM parts are built to match factory specifications exactly, while aftermarket parts are manufactured to fit and perform as a reliable replacement, often at a different price point. Each product listing notes whether the part is OEM or aftermarket so you can choose based on your budget and preference.

Do any of these parts affect emissions compliance or warranty coverage?

Some engine components, particularly those related to exhaust, emissions, or fuel systems, may be subject to EPA or state emissions regulations depending on your truck's engine and model year. Installing non-compliant parts on an emissions-regulated engine can create legal or inspection issues, and modifying certain systems may impact your engine manufacturer's warranty. If you are unsure whether a part is emissions-compliant or how it may affect your existing warranty, check with your engine manufacturer or contact us before purchasing.

Do I need professional installation, or can I install these parts myself?

This depends on the complexity of the part. Simpler items like filters, belts, or sensors are often manageable for an experienced do-it-yourselfer with the right tools. More involved components, such as those tied into the engine's electronic controls, turbo system, or emissions equipment, are generally best installed or at least verified by a qualified diesel technician to avoid performance issues or engine damage. If a listing includes installation instructions or torque specifications, follow them closely regardless of who performs the install.