Cleaning Radiator

The radiator fins clog over time with bugs, dust, and track debris. Since the radiator is rear-mounted, it sees significant debris thrown up by the rear tires. Clean it at the start of each season or whenever you notice elevated coolant temperatures.

Accessing the Radiator

Remove the rear bodywork (rear clamshell) to expose the radiator. The rear clam is held by 2 Aerocatches — no tools required.

Procedure

Airflow through the radiator travels front-to-back: air enters from the sidepod inlets at the front face of the radiator core and exits toward the engine. Debris builds up on the front face (air inlet side).

1. With the rear clamshell removed, inspect the radiator core for debris and fin damage.
2. Using compressed air, blow through the radiator from the front (inlet) side toward the engine — this pushes debris in the direction it entered, clearing it out through the engine side.
3. For stubborn buildup, use a gentle stream of water from a garden hose (not a pressure washer), directed the same way — front face toward engine.
4. Inspect the fins for bending. Carefully straighten any bent fins with a small flathead screwdriver or fin comb — bent fins restrict airflow and reduce cooling capacity.
5. Allow to dry completely before reinstalling bodywork.

Caution

Do not use a pressure washer — the force will bend the aluminum fins and permanently reduce cooling efficiency.

Pin hole leaks

A radiator can develop pin hole leaks that are too small to leave a puddle. They pull air into the cooling system, and the car then overheats even though the coolant level looked fine when you checked it.

The tell is repetition. A car that needs topping up more than once, or that throws a coolant temperature warning shortly after being topped up, is drawing air in somewhere, and the radiator is where to look first given what it sits behind.

Act on coolant temperature warnings rather than clearing them. An overheat you drive through costs an engine, and this failure gives you warning before it gets there. See Dash Alarms.

While the rear clam is off, look over the core for staining or dried coolant residue around the fins and end tanks. A pin hole often leaves a mark even when it is not weeping at the time.

Coolant Check

While the rear is open, it is a good time to inspect coolant condition. The Rush SR uses distilled water + Red Line Water Wetter only. Do not use antifreeze — glycol is a track safety hazard and not permitted. See Changing Coolant and Fluids.