Why won't my reefer trailer hold temperature?
If the refrigeration unit checks out and the box still won't hold temp, the box is leaking cold. The most common cause is a worn door gasket. Damaged insulation, delaminated panels, and a scored floor are the others. Knox Trailers fixes the trailer side of a reefer: doors, gaskets, insulation, floors, lights, wiring, and brakes. For the cooling unit itself, the Carrier or Thermo King, we'll point you to a unit specialist.
Last updated November 12, 2026
The short version
If the refrigeration unit checks out and the box still won't hold temp, the box is leaking cold. The most common cause is a worn door gasket.
- A worn door gasket is the most common reason a box stops holding temp.
- Insulation, panels, and floor damage let cold out even when the unit runs fine.
- Knox repairs the box; unit work goes to a refrigeration specialist.
- Mobile reefer service is available for doors, gaskets, lights, electrical, and brakes.
Do you repair the refrigeration unit?
No. We handle the trailer side: doors, gaskets, insulation, floors, lights, wiring, and brakes. For the unit itself we'll point you to a specialist. Often the temp problem turns out to be the box, and that part we fix.
What do you do about a leaking box?
Replace and adjust door gaskets, hinges, latches, and seals; repair damaged insulation, delaminated panels, and the interior liner; and repair floor scoring, duct floors, and T-rails so air moves the way it should.
Can you fix it if I'm not in Knoxville?
Mobile service covers our service area for door, light, electrical, and brake work. For longer distances we'll triage by phone and help you find a closer shop.
Common questions
Why won't my reefer trailer hold temperature?
If the refrigeration unit checks out and the box still won't hold temp, the box is leaking cold. The most common cause is a worn door gasket. Damaged insulation, delaminated panels, and a scored floor are the others.
Do you repair the refrigeration unit?
No. We handle the trailer side: doors, gaskets, insulation, floors, lights, wiring, and brakes. For the unit itself we'll point you to a specialist. Often the temp problem turns out to be the box, and that part we fix.
What do you do about a leaking box?
Replace and adjust door gaskets, hinges, latches, and seals; repair damaged insulation, delaminated panels, and the interior liner; and repair floor scoring, duct floors, and T-rails so air moves the way it should.
Can you fix it if I'm not in Knoxville?
Mobile service covers our service area for door, light, electrical, and brake work. For longer distances we'll triage by phone and help you find a closer shop.
Need the inspection this week?
Call the shop or request a quote and we will get the trailer on the schedule.