☎ 1-855-557-9883The truck is overheating or losing coolant — should I keep driving to a shop?
No. Driving a hot diesel is the fastest way to turn a hose or radiator repair into an engine replacement — head gaskets and EGR coolers do not forgive it. Stop, shut down, and get eyes on it: most coolant-system failures (hoses, clamps, radiator leaks, water pumps, fan clutches, thermostats) are roadside repairs.
The temptation to nurse it ten more miles has ended a lot of engines. Aluminum radiators, plastic surge tanks, and EGR systems mean a modern diesel tolerates far less overheating than the trucks drivers learned on. If the gauge is climbing or you can smell coolant, the cheap decision is always to stop while the problem is still a cooling-system problem.
On-site, a mechanic pressure-tests the system to find the real leak — hoses and clamps are trivial, radiators can often be temporarily repaired well enough to reach a shop under observation, water pumps and fan clutches are half-day roadside jobs on most trucks, and a stuck thermostat is quick. Service trucks carry premixed coolant; a proper repair includes filling and purging, not just a top-off.
One diagnostic gift you can give the mechanic before they bid: is the coolant going on the ground (look under the truck), into the engine (white sweet-smelling exhaust), or nowhere visible (pressurizing overflow)? Each points somewhere different, and a photo of the puddle helps more than you would think.