Cooling & Heating

Does the temperature climb when the engine is working hard on a track day, or are the heater and air conditioning not working as they should? In this category we bring together parts for the engine cooling system and the cabin heating and ventilation. That includes radiators, water pumps and thermostats as well as fans, air conditioning and heater cores, both for the project car and the daily driver.

What do the cooling system parts do?

The cooling system has to carry away the heat that the engine and oil generate while driving. A radiator transfers heat from the coolant to the air, and the water pump keeps the coolant circulating. The thermostat controls when the main cooling circuit opens. More power and higher boost pressure typically mean more heat, and if the system cannot keep up, there is a risk of overheating. An oil or fluid cooler can help keep temperatures down during hard driving.

How to choose a radiator and cooler

Size alone does not determine performance. Consider several factors together:

• Core construction and thickness, which affect both cooling capacity and airflow
• Space in the engine bay and the position of hose outlets and brackets
• Airflow management, i.e. whether fans and shrouding pull air through the entire core
• Power goals and usage, e.g. street driving, track days or both

In this category you will find brands such as CSF, Mishimoto and Wehrli. Fitment and specifications depend on the specific part number, so always check that the part fits your particular car.

Heating, ventilation and air conditioning

Cabin comfort depends on the heater core, the ventilation ducts and the air conditioning parts. The category also includes cabin air filters, e.g. the aFe Carbon Cabin Air Filter with activated carbon, which can reduce odours and particles in the air blown into the cabin. A clogged filter can cause weaker airflow from the vents, so it is a good idea to check the filter regularly.

Installation and maintenance

If you replace the radiator, water pump or thermostat, the cooling system must be drained, refilled and bled correctly, because air pockets can cause local overheating. Use the coolant type specified by the vehicle manufacturer, and check hoses and clamps for cracks and leaks. An expansion tank or catch can may also be relevant. The expansion tank absorbs the coolant's expansion as it heats up. A catch can collects oil and condensation from the crankcase ventilation. The brands Gates and J&L are also available in the category.

Frequently asked questions

When does a larger radiator make sense?

Typically when the engine gets more power, or when the car is used for track days. However, cooling capacity also depends on core construction, airflow and the fans, so a larger radiator will not necessarily solve the problem on its own.

Why does the engine warm up slowly, and why is the cabin heat weak?

This can be caused by a thermostat stuck in the open position, so the coolant flows through the radiator all the time. Check the thermostat before replacing other parts of the heating system.

Why does the cooling system need to be bled after installation?

Air pockets can prevent the coolant from circulating properly and cause local overheating. The procedure depends on the car, so follow the manufacturer's instructions for filling and bleeding.

Do modifications to the cooling system require approval for inspection?

It depends on the product and the car. For conversions that change the front end, shrouding or radiator position, you should check the requirements for the specific part number and your car before installing the part.