How to Troubleshoot the Cooling System in a VW Passat

Identify cooling system problems by understanding the way it functions. Simply put, coolant picks up heat when it goes through the engine and releases heat in the radiator. Cooling devices work by circulating antifreeze, containing it or controlling its temperature. Troubleshoot the cooling system in a VW Passat by inspecting cooling system devices. Team up with a mechanic for these steps that relate to most model years.

Instructions

1

See if your water pump is leaking. The water pump pushes coolant through the engine, radiator and heater core. A faint coolant smell or spots of it under your Passat when parked briefly indicate a worn out water pump.

2

Search for cracked, collapsed, leaking or dry hoses. Inspect the upper and lower radiator hoses, heater and bypass hoses and manifold coolant hoses. Your upper hoses measure about 2 inches wide and carry coolant between the radiator and engine. Damaged hoses lead to cooling system problems.

3

Check the antifreeze amount. Overheating and other cooling problems can result from low coolant levels. In this case, put extended life antifreeze in the coolant reservoir. Use a brand recommended for 5 years or 150,000 miles. This applies to the four-cylinder and six-cylinder engines.

4

Drain and flush the cooling system to pinpoint problems. Dispose of coolant properly because the sweet smell and bright antifreeze color is attractive to animals and small children. Ingesting the poisonous liquid can be deadly.

5

Inspect the radiator cap for signs of wear and tear. For example, a damaged cap can erode. Ask a mechanic to use a pressure tester or an adapter to inspect the cap's pressure rating and functioning. Replace a defective cap right away.

6

Wash and gently scrub the front of your radiator. When you drive, dirt, rocks, leaves and other debris suck into the vents of your radiator resulting in overheating. Clean it with soapy water, a soft nylon brush, and a garden hose to rinse.

7

Examine the thermostat for sticking. Pinpoint a sticking thermostat with constant low temperature readings or peaks between high and normal temperatures. Your thermostat, the spring-loaded valve that reacts to coolant temperatures, is generally located inside the housing on the engine side of the upper radiator hose.