Honda Civic CVT Transmission Oil Cooler Kit 1.5T

This is a bolt-on auxiliary transmission fluid cooler kit built for the 2016-2021 Honda Civic with the 1.5L turbo and the CVT. It is an ETL Performance kit, manufacturer part number 244003. It is not a replacement for the factory cooler - it is an added stage of cooling plumbed in ahead of it, which is what the 1.5T CVT cars need once they see stop-and-go traffic, mountain grades, or any kind of sustained load.

The CVT in these cars runs its fluid through a small factory heat exchanger that is sized for average use. When CVT fluid temperature climbs and stays up, the fluid thins out, the pulleys lose clamping pressure on the belt, and you start feeling the classic symptoms: shudder or judder under light throttle at 20-40 mph, a rubber-band feel when you get into it, and in the worst cases the car dropping into a reduced-power limp mode until it cools off. Heat is also what kills the fluid itself - once it oxidizes, the friction modifiers are gone and belt and pulley wear accelerates.

The kit uses a tube-and-fin cooler core with a machined aluminum thermostatic adapter block that sandwiches at the factory cooler port. The thermostat matters: it keeps the auxiliary cooler out of the loop until the fluid is up to temperature, so you are not running cold, thick CVT fluid in winter, which causes its own driveability problems. Included in the box is the cooler core, the adapter housing with O-rings, rubber cooler line, two steel mounting brackets, hose clamps, and the bolt and washer hardware.

Installation is a direct fit with no cutting or drilling. The cooler mounts in front of the condenser using the supplied brackets, the adapter block installs at the factory cooler location, and the supplied line routes between them. Expect to lose some fluid at the adapter - have CVT fluid on hand to top off and check level at temperature per the service procedure when you are done.