Parts for your 2025 Mitsubishi Eclipse cross-Drive belt tensioner

Drive-belt tensioner — 2025 Mitsubishi Eclipse Cross

Short answer: it depends on the variant. The 2025 Mitsubishi Eclipse Cross with the 1.5‑litre turbo petrol engine uses a serpentine drive-belt with an automatic drive-belt tensioner. The 2025 Eclipse Cross PHEV does not use a conventional accessory drive-belt or a belt tensioner.

References to technical sources: Mitsubishi Motors Eclipse Cross Service Manual for the 4B40 1.5T engine (Drive Belt/Auto‑tensioner sections), Mitsubishi ASA electronic parts catalogue for Eclipse Cross (YA series/MY2025), aftermarket catalogues from major belt system manufacturers listing a tensioner for the 1.5T petrol, and the Eclipse Cross PHEV workshop manual noting the use of an electric A/C compressor, electric cooling pump(s) and DC‑DC converter in place of alternator—hence no accessory drive-belt on PHEV. The Owner’s/Service schedules also reflect a V‑ribbed belt check for petrol models, not for PHEV.

Why the PHEV doesn’t run a tensioner: the hybrid layout powers accessories electrically, and the engine doesn’t drive an alternator via a belt. With no external accessory belt, there’s no need for a drive-belt tensioner on the PHEV.

For petrol models that do have a tensioner, here’s what drivers and techs should know. The drive-belt tensioner keeps the V‑ribbed (serpentine) belt at the right tension across the accessory pulleys, most notably the alternator and A/C compressor. It’s a spring‑loaded, self‑adjusting unit designed to maintain grip as the belt beds in and as loads change. Good tension prevents belt slip, squeal and glazing, and it helps the alternator charge reliably while keeping the A/C cold under load. A healthy tensioner also minimises flutter, reduces shock loads on bearings and extends belt life.

As part of routine servicing on a 2025 Eclipse Cross petrol, it’s smart to inspect the belt and tensioner together. Listen for chirps at start‑up, rattles around idle, or intermittent squeal with A/C on—classic signs of a weak spring or a rough pulley bearing. Under the bonnet, check the tensioner arm moves smoothly through its arc, that the pulley spins freely with no wobble, and that the belt tracks centrally on every pulley. Any frayed edges, cracking, or dust build‑up can hint at misalignment or a tired tensioner.

Replacement is typically done with the belt off, most workshops will replace the belt and tensioner as a pair, and often the idler pulley(s) too. On high‑kilometre vehicles—think roughly 100,000 to 150,000 km—or if there’s noise, slip, or poor charge voltage, swapping the lot avoids repeat visits. Use quality OE‑equivalent parts, follow the correct torque specs for the tensioner mounting bolt, and confirm alignment with the engine running. After fitting, recheck belt tracking and listen for any residual noise. Done right, a fresh belt and tensioner combo will be quiet, charge strongly and handle Aussie and Kiwi summer A/C loads without breaking a sweat.

• Petrol (1.5T): drive-belt tensioner fitted — inspect each service, replace if noisy, misaligned or at high kms.
• PHEV: no accessory belt — therefore no drive-belt tensioner required.

Popular questions

Does the 2025 Eclipse Cross PHEV have a drive-belt tensioner?
The PHEV doesn’t run a conventional accessory belt, so there’s no drive-belt tensioner. Its key accessories are electrically driven, and the DC‑DC converter replaces a belt‑driven alternator. That’s why there’s nothing to tension in the first place.

What are the signs the drive-belt tensioner is failing on the 1.5T petrol?
Listen for chirping or squealing on cold starts, rattles at idle, or intermittent belt noise when you load up the A/C. Visually, look for belt flutter, frayed edges or the tensioner arm sitting off‑centre. A rough or wobbly pulley and poor alternator charge voltage are also red flags.

When should the tensioner be replaced on a 2025 Eclipse Cross petrol?
Have it checked at every service and consider replacement with the belt somewhere around 100,000–150,000 km, or sooner if there’s noise, tracking issues or bearing play. Many techs swap the belt, tensioner and idler together to keep the system quiet and reliable.