Engine Cooling Repair


There are two types of cooling systems found on motor vehicles: Liquid-cooled and Air-cooled.

Older automobiles like the original Volkswagen Beetle and the Chevrolet Corvair had air-cooled engines, and modern motorcycles still use air cooling, but most of today’s cars, like Hondas, Subarus and Toyotas, utilize liquid-cooled systems. Your vehicle’s cooling system is made up of the following components:

  • Passages inside the engine block and heads
  • A water pump that circulates your engine coolant
  • A thermostat that controls the temperature of the engine coolant
  • A radiator that reduces the temperature of the engine coolant
  • A radiator cap that controls the pressure in the system
  • Interconnecting hoses that transfer the coolant from your engine to the radiator and also to your car’s interior heating system (coolant that has been heated is used to warm up your vehicle’s interior)

As you operate your vehicle, the cooling system circulates liquid coolant through passages in your engine block and heads, where it absorbs heat from the engine and then makes its way through a rubber hose to the radiator in the front of the car. Flowing through thin tubes in your radiator, the hot liquid is cooled by the wind that enters the engine compartment from the grill in front of your car. After this, the now-cooled fluid is circulated back to the engine to absorb more heat. Throughout the duration of this process, your water pump has the job of keeping the fluid moving through this plumbing system and hidden passages.

Between your engine and the radiator is your thermostat, which ensures that your coolant stays above a certain preset temperature. If the coolant temperature falls below this prescribed temperature, your thermostat will block the coolant flow to the radiator, forcing the fluid directly back to the engine via a bypass. Coolant will continue to circulate in this manner until it reaches the optimal temperature. At this point, your thermostat will open a valve and allow the coolant back through the radiator. Cooling systems are pressurized, which prevents the coolant from boiling. (The boiling point of engine coolant is raised considerably by pressure.) However, too much pressure will cause hoses and other parts to burst, so a system is needed to relieve pressure if it exceeds a certain point. The job of maintaining the pressure in your cooling system belongs to the radiator cap, which is designed to release pressure if it reaches the specified upper limit. In the old days, the cap would release this extra pressure right out onto the ground. Modern cars have an added system that captures any released fluids and stores-it temporarily in a reserve tank and then returns to the cooling system after the engine cooled down. This is what is called a closed cooling system.

What we’ve just described to you is a complex system that presents more than one opportunity for problems to happen. Northwest Best Auto Repair specializes in repairing Hondas, Toyotas, and Subarus, and we equip our expert technicians with the latest high-tech computers and diagnostic equipment so that they can inspect your car and diagnose the exact cause of any car coolant problem. Our goal is to repair your vehicle properly and get you back on the road quickly, and safely. We proudly keep our customers’ engines running at optimal temperatures in greater Seattle. We dedicate every day to providing the highest level of customer service, with honest recommendations and repairs.

Give us a call now at 206-420-4987 to make an appointment, and then come on down to our comfortable waiting area while our extremely efficient technicians give you dealership-quality service...at a neighborhood-shop price!

Schedule this service or call 206-420-4987