Parts for your 1998 Daihatsu Gran move-Heater core

1998 Daihatsu Gran Move (Pyzar) heater core — what it does and how to look after it

Based on the Daihatsu service manual Heating & Air Conditioning section for the L5-series Gran Move/Pyzar, and the Daihatsu Electronic Parts Catalogue (group 87: Heater Unit), the 1998 Gran Move is fitted with a conventional heater core inside the HVAC case behind the dash. Comparable listings in aftermarket workshop data and Charade-based references back this up. So yes, this model absolutely uses a heater core.

The heater core is a small radiator that takes hot engine coolant and uses it to warm air for the cabin and to demist the windscreen. On a tidy 1998 Gran Move, a healthy core means quick winter warmth, clear glass, and stable engine temps. If the core clogs or leaks, you’ll cop weak heating, foggy windows, a sweet coolant smell, damp carpet on the passenger side, or slow coolant loss.

Good servicing of your 1998-daihatsu-gran-move heater-core starts with the cooling system. Stick to fresh, manufacturer-approved coolant and distilled water, and flush the system at sensible intervals (typically every 2 years or 40,000 km, or as per your service data). Bleed air properly after any cooling work, trapped air can starve the core and cause poor heat. If your Gran Move has a cabin/pollen filter (some markets didn’t), replace it regularly to keep airflow up.

• Watch for a sweet odour in the cabin, oily film on the inside of the screen, or damp underlay — classic leak signs.
• Check heater hoses at the firewall for age cracks and clamps for tension.
• Don’t mix coolant types, contamination can sludge up the core.

Replacement is a fair DIY for the patient, but many owners prefer a technician. Expect several hours’ labour. The A/C system usually doesn’t need to be discharged if you separate the heater section only, but follow the manual closely.

1. Disconnect the battery and let the engine cool. Drain coolant.
2. Inside, remove the glovebox and lower trims, on this RHD model, the heater unit sits near the centre/passenger side.
3. In the engine bay, clamp and disconnect the two heater hoses at the firewall.
4. Unbolt the heater case halves as specified, slide the core out, catching any residual coolant.
5. Install the new core with fresh O-rings and foam seals, reassemble carefully to avoid cracking aged plastics.
6. Refit hoses, refill with the correct coolant mix, bleed air, and pressure-test for leaks. Verify hot/cold blend and fan operation.

Handy tips: have replacement hose clamps ready, protect the carpet, and take photos as you go. If the dash plastics are brittle with age, a trim tool and gentle heat can save tabs and clips.

Where is the heater core on a 1998 Gran Move?
It sits inside the HVAC box behind the dash, generally accessed from the passenger side once the glovebox and lower panels are off. The inlet and outlet hoses pass through the firewall on the passenger side of the engine bay.

What are the signs the heater core is failing?
Weak cabin heat, a sweet coolant smell, misty windows with an oily film, or a damp passenger footwell are common. You might also notice slow coolant loss without external drips and a heater that goes hot–cold due to air in the system.

Can the heater core be bypassed temporarily?
Yes, in a pinch you can loop the two heater hoses in the engine bay to stop a leak and keep the vehicle mobile. You’ll lose cabin heat and demist performance, so treat it as a short-term fix only and repair or replace the core promptly.