Cooling System
Repair And Service

Overheating diagnosis at Torpedo follows a systematic approach — not a parts replacement chain. We begin with a cooling system pressure test, a coolant condition test, and a thermostat operation check before any components are removed. Many overheating complaints trace back to a single failed item, and identifying it correctly on the first visit prevents unnecessary repair costs.

We check for combustion gas contamination in the coolant using a combustion leak test kit — an early indicator of a head gasket failure that produces overheating without visible white smoke. Coolant temperature sensor accuracy is verified with a calibrated pyrometer to confirm the gauge reading matches actual engine temperature before any diagnosis is complete.

• Cooling system pressure decay tested before and after repair
• Coolant pH and freeze point measured and corrected
• Engine temperature verified at operating load after repair

Radiator inspection covers fin condition, core integrity, and tank-to-core joint integrity. Clogged radiator cores reduce heat rejection capacity and cause overheating under sustained load even when all other cooling components are functioning correctly. We flow-test the radiator and inspect the core for internal scale buildup before recommending repair or replacement.

Radiator repairs cover leak sealing at tank-to-core joints and plastic tank repairs where the damage is isolated and the core is in acceptable condition. Full radiator replacement is recommended when the core shows significant restriction, multiple leak points, or physical damage that compromises structural integrity under operating pressure.

• Pressure cap tested and replaced if not holding rated pressure
• Surge tank and overflow system inspected with every radiator job
• Radiator mounts and vibration isolators checked and replaced if worn

Water pump inspection covers shaft seal condition, bearing play, impeller condition, and housing integrity. A water pump with a weeping shaft seal is replaced before it fails completely — a sudden water pump failure causes rapid overheating that can result in cylinder head damage in the time it takes to pull over and shut down the engine.

Timing-driven water pump replacements on diesel engines are coordinated with timing belt or gear inspection to avoid duplicate labor on engines where the timing system must be partially disassembled to access the water pump. We inspect all timing components during the pump replacement and report findings before reassembly.

• Coolant system flushed with every water pump replacement
• New thermostat installed with every water pump as a set
• Cooling system burped and air-bleed confirmed before test drive

Thermostat testing confirms the thermostat opens at the correct temperature and opens fully when hot. A thermostat that is stuck partially open allows coolant to bypass before the engine reaches operating temperature — causing low running temperature, poor fuel economy, and white smoke on cold starts that is frequently misdiagnosed as a more serious issue.

Thermostat housing inspection covers the housing itself for cracks and the sealing surface for corrosion. Corroded or pitted thermostat housing sealing surfaces cause coolant leaks that continue after thermostat replacement and are a frequent source of repeat repairs when the housing itself is not addressed during the initial service.

• Coolant temperature sensor replaced if out of calibration
• Housing gasket surfaces cleaned and inspected before reassembly
• Operating temperature confirmed within specification after thermostat replacement

Fan clutch testing covers engagement temperature, slip at operating temperature, and drive ratio at high coolant temperature. A fan clutch that does not engage fully at the correct temperature reduces airflow through the radiator at slow vehicle speeds and under high load — conditions where the engine depends most on the fan for cooling capacity.

Fan clutch replacement on Class 8 trucks includes inspection of the fan blade for cracks, pitch, and tip clearance to the shroud. A cracked fan blade is a catastrophic failure risk and is inspected carefully during every fan service. Fan-to-shroud clearance is verified to ensure maximum airflow efficiency after the new clutch is installed.

• Engine fan belt and tensioner inspected with every fan clutch job
• Fan shroud condition and mounting verified after replacement
• Coolant temperature at fan engagement confirmed with calibrated gauge

Cooling system flush service removes depleted coolant, scale deposits, and rust from the system using a chemical flush and thorough rinsing. Scale buildup inside the block and head passages significantly reduces heat transfer efficiency and is a contributing factor in overheating complaints on high-mileage trucks where the coolant has not been serviced on schedule.

Extended-life coolant maintenance requires SCA (supplemental coolant additive) testing to verify inhibitor concentration. Diesel engine cooling systems require specific inhibitor levels to prevent liner pitting from cavitation — a common and expensive failure mode in high-horsepower diesel engines that is completely preventable with proper coolant maintenance.

• Coolant SCA level tested and corrected to specification
• Hoses and clamps inspected and replaced as needed during flush
• System refilled to correct concentration for regional climate conditions