Radiator Problems

RADIATOR PROBLEMS

Plugged Radiator - Corrosion, sediment, or excess silicone sealant is blocking the flow of coolant through the radiator. Corrosion build up along the inside of the cooling tubes also insulates the coolant from the air flowing through the radiator and reduces the amount of cooling.

Leaking Radiator

Cooling Tube Damage - The cooling tubes have been physically damaged or severe corrosion has rusted through the tubes.



Water Box Seal Leak - The main seal between the water box and cooling fins is leaking. The cooling fins are crimped onto the water boxes, excessive pressure, temperature, or old age may cause these seals to leak.

CAUTION: When pressure testing a radiator, never exceed the rated pressure of the radiator cap. Exceeding this pressure may damage the water box seals.




Cracked Seams - Welded/soldered seams, usually around the inlet and outlet tubes, are cracked. These cracks are often the result of excessive force when removing radiator hoses or excessive hose clamp pressure.

SYMPTOMS

Plugged Radiator
- Engine gradually overheats under all conditions, regardless of driving speed.
- Coolant may show signs of heavy rust contamination, and there may have recently been problems with leaking freeze plugs.

Radiator Leaks
- Coolant visibly leaking from or around the radiator.

NOTE: The coolant leak may be very slight at first, and may require pressurization to become evident.

- Cold coolant expansion tank levels drops after every trip.

HOW TO VERIFY

Plugged Radiator
- Inspect the condition of the radiator coolant and if possible view the coolant passages through the radiator cap. If the radiator is plugged:
- The coolant may be heavily contaminated with rust.
- The coolant passages may be visibly blocked with corrosion, scale, or silicone sealant.
- Verify the operation of thermostat and cooling fan.



- Verify coolant hoses are not restricted or pinched.
- Check the difference in temperature between the upper hose and lower hose. If the radiator is plugged:

- The upper hose will become extremely hot while the lower hose will also become hot.

NOTE: There may still be a temperature difference (10- 20°) between the upper and lower radiator hoses because of the air flow across the radiator.

WARNING: Use a surface thermometer or infrared temperature gun to determine hose temperature. Do not attempt the feel the temperature by hand, this may result in serious personal injury.

- The upper hose may appear pressurized/hard while the lower hose may de-pressurized/soft (or in extreme cases may be sucked inwards)

NOTE: Plugged radiators may be flushed or rodded-out. Rodding-out a radiator involves removing water boxes and running a rod through the internal coolant passages to remove any built up corrosion or scale.

Radiator Leaks
- With the engine cold, verify the cooling system is filled with coolant and fill if necessary. Inspect the radiator for leaks.




- Using a pressure tester, pressurize the cooling system and inspect for leaks.

NOTE: If leaks are detected at or near the radiator hose connections, inspect the flanges closely for cracks.