Parts for your 2004 Honda Stream-Radiator

2004 Honda Stream Radiator — purpose, care, and when to replace

Yes, the 2004 Honda Stream uses a radiator. Technical sources including the Honda Stream RN1–RN5 Workshop Manual, the Honda Electronic Parts Catalogue, and Autodata’s model data all specify a liquid-cooled inline-four (D17A 1.7L or K20A/K20A3 2.0L) with a front-mounted aluminium crossflow radiator. Automatic variants also route transmission fluid through an in-tank heat exchanger in the radiator.

The radiator’s job is simple but critical: it dumps engine heat into the airstream so the Stream runs at a stable operating temp, usually in the 80–90°C range. Coolant leaves the engine hot, passes through the radiator core, and is cooled by airflow and the twin electric fans before looping back in. That temperature control protects gaskets, the head, and the automatic transmission (on auto models), and it keeps the cabin heater working properly on cold mornings.

As part of regular servicing, the Stream’s cooling system likes fresh, correct coolant and a healthy radiator cap. Honda specifies silicate-free, long-life coolant (Honda Type 2 or equivalent) premixed 50/50. First fill was long-life, but in everyday Aussie and Kiwi use it’s smart to change coolant about every 5 years or 100,000 km, then keep an eye on it annually. Check for crusty green/white stains on the end tanks, dampness around the top hose neck, brittle hoses, and any sweet smell after a drive — all early clues a radiator is on the way out. For autos, watch the ATF colour, a pink/milky look can indicate a failed in-tank cooler.

When replacing, a quality aluminium/plastic unit to the RN1–RN5 spec is the go. Swap the fan shrouds across, fit new hoses and clamps, and don’t forget the 1.1 bar cap. Autos need the ATF cooler lines transferred and securely clamped, plug the lines while the radiator’s out to avoid drips. Refill with the right coolant, heater on hot, bleed patiently, and confirm both fans cut in once the thermostat opens. Dispose of old coolant responsibly.

• Service interval guide: inspect every service, replace coolant ~5 years/100,000 km.
• Common symptoms: creeping temp gauge, coolant loss, stained fins, swollen tanks, weak heater, or milky ATF (autos).
• Pro tips: use demineralised water if mixing, straighten bent fins gently, and never top up hot with cold water.

Popular questions

What coolant should a 2004 Honda Stream use, and how often?

Honda Type 2 long-life coolant (or an equivalent silicate-free, phosphate formulation) premixed 50/50 is recommended. In local conditions, change it about every 5 years or 100,000 km after the factory fill, and inspect level/condition at each service.

How can someone tell the Stream’s radiator needs replacing?

Look for white/green crust on the plastic end tanks or around the top hose neck, damp patches, sweet smells after driving, rising temps in traffic, or discoloured coolant. On autos, a milky look to ATF hints at an internal cooler leak — replace the radiator immediately and service the transmission fluid.

Does the 2004 Honda Stream radiator include a transmission cooler?

On automatic models, yes — there’s an integrated ATF heat exchanger inside the radiator tank. Manual models don’t use this feature. When replacing the radiator on an auto, always reconnect and secure the ATF lines and check fluid level after the job.