Symptoms of a Faulty or Faulty Heater Bypass Tube

If you see a coolant leak under your vehicle or a coolant smell from your vehicle, you may need to replace the heater bypass pipe.

The heater bypass pipe is a cooling system component found on many road cars and trucks. It is designed to serve as a channel for the cooling system to bypass the thermostat so that coolant flows even when the engine thermostat is closed. The coolant bypass pipe provides a minimum coolant flow passage so that the engine does not overheat due to insufficient cooling when the thermostat is closed and restricts coolant flow.

Although bypass pipe maintenance is not usually considered a routine service, it is still subject to the same problems that all components of the cooling system are subject to and can sometimes require attention. Usually, a faulty heater bypass tube causes several symptoms that may alert the driver to a problem.

Smell of coolant

One of the signs of a problem with the heater bypass pipe is the smell of coolant from the engine compartment. Most heater bypass pipes use an O-ring or gasket to seal the bypass pipe to the engine. If the O-ring or gasket becomes worn or torn, coolant will leak from the bypass tube. This can cause coolant odor from the vehicle's engine compartment. Some coolant bypass pipes are located on top of the engine, which can cause coolant odor long before it can be visually detected without opening the hood.

Leaking coolant

The most common symptom of a heater bypass tube problem is a coolant leak. If the bypass tube gasket or O-ring is damaged, or the bypass tube is leaking due to excessive corrosion, coolant may leak. Depending on the severity of the leak, coolant may or may not leak onto the floor or under the vehicle. A failed gasket or o-ring may require a simple seal replacement, while a corroded tube usually requires replacement.

Because the coolant bypass pipe is a component of the engine cooling system, failure of the bypass pipe can cause the engine to overheat and potentially cause severe engine damage. If your vehicle's bypass pipe is leaking or has other problems, have your vehicle checked by a professional technician such as AvtoTachki to determine if the bypass pipe needs to be replaced.