Parts for your 2015 Mitsubishi Asx-Heater hose

2015 Mitsubishi ASX heater hose — what it does and how to look after it

Yes, the 2015 Mitsubishi ASX uses heater hoses. This is supported by Mitsubishi Motors technical literature: the ASX/RVR/Outlander Sport service manual for GA2W/GA3W (2010–2017) identifies heater water hoses in Group 55 (Heater — heater core and water hoses), and the MMC ASA electronic parts catalogue lists dedicated “heater water hose, inlet/outlet” for 2015 ASX models with the 2.0L engine. So a heater-hose is absolutely relevant on this vehicle.

On the ASX, the heater hoses are the rubber lines that carry hot engine coolant to and from the heater core inside the dash. When the driver dials up the heat, air passes through that hot core and warms the cabin. Those hoses are part of the engine’s cooling loop, so they also impact engine temperature stability. If they perish or leak, they can cause coolant loss, poor cabin heat, temperature swings, and in a worst case, engine overheating.

As the ASX ages, the hoses live through a lot of heat cycles. They can harden, soften, swell, or crack. Common signs it’s time to act include a sweet coolant smell near the firewall, damp spots or staining on the transmission tunnel side of the engine bay, low coolant in the reservoir, white crust at clamps, and hoses that feel spongy or, conversely, rock-hard and cracked.

• Inspection: At every service (around 10,000–15,000 km or 12 months), check the heater hoses from the engine to the firewall. Look for bulges, abrasions, oil contamination, and leaks at clamp points.
• Replacement timing: Many techs recommend preventive replacement at 8–10 years or 150,000–200,000 km, or sooner if wear is evident. Do them as a pair with new quality spring or constant-tension clamps.
• Coolant: Refill with Mitsubishi-approved ethylene-glycol coolant mixed to spec (commonly 50/50). Don’t mix types, if unsure what’s in there, drain and refill completely.
• Fitment tips: Work on a stone-cold engine. Catch and dispose of coolant responsibly. Lightly lubricate hose ends with fresh coolant, position clamps behind the bead, and orient them for future access. After refilling, set the heater to HOT and bleed air thoroughly, bring the engine to operating temp and recheck the level and for leaks.
• Longevity: Keep oil off the hoses (oil degrades rubber) and ensure proper engine earths and cooling fans so hoses aren’t overstressed by excessive heat.

Looked after properly, fresh heater hoses help the ASX deliver reliable cabin warmth and stable engine temps through Aussie summers and Kiwi winters alike.

Popular questions about 2015 Mitsubishi ASX heater hoses

Where are the heater hoses on a 2015 ASX?
They run from the engine side of the bay to the firewall on the passenger side, connecting the engine cooling circuit to the heater core inside the dash. You’ll typically see two rubber hoses entering the firewall, with spring or constant-tension clamps.

Tracing them is easiest when the engine is cool: follow the smaller-diameter coolant hoses from the thermostat housing/water outlet area towards the firewall.

How often should the heater hoses be replaced?
There’s no single fixed interval, but a practical rule is replace around 8–10 years or 150,000–200,000 km, or immediately if any cracking, swelling, soft spots, or leaks are found. Inspect them at every service and after any overheating event.

When in doubt, preventive replacement is cheaper than a tow and potential engine damage from coolant loss.

What coolant should be used after hose replacement?
Use a Mitsubishi-approved ethylene glycol coolant at the correct dilution (often 50/50 premix). Avoid topping up with a different coolant type. If the existing coolant type is unknown, do a full drain and refill with the correct product.

Always bleed the system with the heater on HOT to avoid air pockets that can cause poor cabin heat or temperature fluctuations.