Peterbilt 386 Coolant Reservoirs

OEM reservoirs are made by or for the original truck manufacturer and are guaranteed to match factory specifications exactly. Aftermarket reservoirs, like our OEM-equivalent options, are engineered to the same fit, form, and function at a more competitive price point, often with comparable materials and warranty coverage.

Common signs include visible cracks, coolant leaks around the tank, low coolant warnings despite topping off fluid, discoloration from UV or heat damage, and a cap that no longer seals properly. If your engine runs hot intermittently or you notice coolant puddles under the truck, inspect the reservoir immediately.

Most coolant reservoirs for the Peterbilt 386, including OEM units, are manufactured from high-density polyethylene (HDPE) plastic designed to withstand engine heat and coolant pressure. Some heavy-duty or specialty applications may use reinforced composite materials for added durability in demanding environments.

Yes, our inventory covers reservoir and surge tanks for multiple Peterbilt models as well as Kenworth, Freightliner, International, and other major truck manufacturers. Contact our team with your model and VIN details so we can confirm the correct part for your specific application.

Shipping times vary based on stock availability and destination, and specific delivery windows aren't listed on our standard product pages. We recommend contacting our team directly at the time of order to get an accurate shipping estimate and confirm expedited options if you need the part quickly.

Cracking and leaking are usually caused by prolonged UV exposure, extreme temperature cycling, road debris impact, or age-related material fatigue in the plastic tank. Overpressurization from a failing radiator cap or cooling system blockage can also stress the reservoir walls, leading to premature failure.