Laredo summers put truck cooling systems to the test.
Long stretches of triple-digit afternoons, trucks idling in bridge lines with the A/C running, and heavy loads on I-35 all push engine temperatures to the limit. A cooling system that barely kept up in spring can fail in the first really hot week of the year.
Overheating is one of the fastest ways to turn a small repair into a big one. An inexpensive hose that lets go can warp a cylinder head or damage a liner if the driver keeps going. The earlier the problem is caught, the more likely it is to be a hose, a clamp, a belt, or a fan clutch — and not an engine.
What our Cooling System & Radiator Repair covers
- Radiator and heater hose replacement
- Hose clamp and coolant pipe leaks
- Fan and serpentine belt replacement, plus belt tensioners and idler pulleys
- Fan clutch diagnosis — engaging when it should, and not dragging when it shouldn’t
- Fan clutch air solenoid and air line problems
- Water pump replacement on many engines, depending on access
- Thermostat replacement
- Coolant temperature sensor and coolant level sensor faults
- Surge tank and pressure cap problems
- Pressure testing the cooling system to find leaks
- Topping off with the correct coolant type for your engine
- Checking radiator and charge air cooler fins for debris blocking airflow
What can't be done on the roadside
- Radiator replacement on trucks where it means removing the hood and front-end components — often a shop job
- Radiator core repair and recoring
- Head gasket, cylinder liner, or oil cooler failures that put coolant in the oil or oil in the coolant
- EGR cooler replacement on engines where it requires extensive disassembly
If you see milky oil on the dipstick or oil floating in the coolant reservoir, don’t run the engine. Those are signs of an internal leak that needs a shop.
Fix it on site or tow it?
Hoses, belts, clamps, thermostats, fan clutches, and sensors are routine on-site repairs. If the engine overheated briefly and was shut down promptly, replacing the failed part and refilling coolant often gets the truck back on the road the same day.
A tow is smarter if the engine ran hot for a long time, shows signs of internal damage, or lost its coolant and kept running. Never open a hot radiator cap or surge tank — the coolant is under pressure and can cause severe burns. Let the system cool before anyone touches it.
What to tell dispatch when you call
The more dispatch knows up front, the better the odds the mechanic shows up with the right parts and tools on the first trip.
- How hot the gauge got and how long the truck ran that way
- Whether you see steam, coolant on the ground, or a burst hose
- Whether a belt is broken or the fan isn’t turning
- Any coolant warning light or fault code
- Whether the engine is shut down now
Truck makes & engines we work on
- Freightliner
- Peterbilt
- Kenworth
- Volvo
- Mack
- International
- Western Star
Class 6 through Class 8 trucks, including engines from Cummins, Detroit Diesel, PACCAR, Volvo, Mack, Navistar, and Caterpillar.
Cooling System & Radiator Repair around Laredo & South Texas
Overheating calls around Laredo peak in the summer months and come from everywhere: bridge traffic on Loop 20 and Mines Road, northbound I-35 under heavy loads, and trucks idling for hours at docks and in staging lots with the A/C running.
Highways
Towns
Cooling System & Radiator Repair FAQ
My truck is overheating. What should I do first?
Get off the road safely, take load off the engine, and shut it down if the gauge is in the red or a stop-engine light is on. Don’t open the radiator cap on a hot engine. Then call.
Can I just add water to the radiator?
In an emergency, water can get you off the highway, but it dilutes the coolant’s protection. Have the system drained or topped off with the correct coolant as soon as possible.
Why does my truck overheat only in traffic?
At low speed there’s no ram air through the radiator, so the fan does all the work. A fan clutch that isn’t fully engaging is a common cause, along with a radiator packed with dirt and debris.
Why does my truck overheat on the highway but not in town?
Sustained load needs full cooling capacity. A partly plugged radiator, weak water pump, sticking thermostat, or low coolant may keep up in town but fall behind at highway speed under load.
Does coolant type matter?
Yes. Mixing incompatible coolant types can cause problems. Tell dispatch your engine make so the right coolant is used to match what’s already in the system.
How do I know if overheating damaged the engine?
Warning signs include coolant in the oil, oil in the coolant, white exhaust smoke with a sweet smell, or loss of compression. A mechanic can pressure test the system and check for these before you run it again.