Radiator Problems: Restriction, Leaks, and External Blockage
A radiator that can't shed heat will overheat the truck under load. We cover external blockage, internal scale, and seam leaks.
External blockage
The most common radiator fault is external — bugs, dirt, and debris packing the fins, often behind the charge-air cooler, blocking airflow. We inspect and clean the radiator and CAC fins with low-pressure water and verify airflow. A radiator that looks clean from the front may be packed at the back.
Internal restriction
Internal scale, sediment, or stop-leak products restrict flow through the tubes, reducing cooling capacity. We check for cold spots across the radiator face with the engine warm — even temperature means good flow, cold patches mean blocked tubes. A radiator with multiple blocked tubes needs service or replacement, and we flush the system to stop the cause (often contaminated or wrong coolant).
Leaks and seams
Plastic-tank radiators leak at the tank-to-core crimp, the seam, or a cracked tank; all-metal radiators leak at soldered joints or from road damage. We pressure-test to confirm the source. A leaking seam on a plastic-tank radiator usually means a replacement; a small metal-core leak can sometimes be repaired.
Our mobile diesel technicians carry the tools and parts to diagnose and fix this on the shoulder or at your yard — 24/7/365 across Colorado, Wyoming, and Texas.
(303) 476-3622An overheating diesel will warp heads and crack liners in minutes. We cover the diagnosis path and why pulling over is non-negotiable.
A slow coolant loss is a warning. We cover external leak sources and the internal leaks — EGR cooler, liner — that mean engine damage.
The fan clutch engages the cooling fan when airflow is needed. When it fails, the truck overheats climbing grades or sitting still.