Parts for your 2018 Subaru Impreza-Drive belt

2018 Subaru Impreza Drive Belt — What It Does and When to Replace

Technical references for this model — the 2018 Subaru Impreza Owner’s Manual, Subaru FB20 engine service literature, and mainstream belt catalogues from Gates and Dayco — confirm the car runs an external multi‑rib accessory drive belt (often called a serpentine belt). The FB‑series 2.0‑litre engine uses a timing chain (so there’s no timing belt), while the accessory drive belt powers key ancillaries.

On a 2018 Impreza, the drive belt’s main jobs are to spin the alternator and the air‑conditioning compressor. Power steering is electric on this model, so there’s no hydraulic pump on the belt, and the water pump is driven internally, not by the accessory belt. Even so, this unassuming belt is vital — if it slips or breaks, charging stops, the battery light pops on, and A/C performance drops to nothing.

As part of regular servicing, the belt should be inspected under the bonnet for wear and correct tension. Subaru’s guidance is largely condition‑based: check it at routine service intervals and replace when wear shows. In Aussie and Kiwi conditions — heat, stop‑start traffic, dust and the odd spirited weekend — many belts comfortably last 100,000 to 160,000 km, but it’s smart to act on condition rather than a fixed kilometre figure.

• Common wear signs: fine cracking across the ribs, frayed edges, missing rib sections, glazing/shiny patches, rubber dust, or chirping/squealing on start‑up.
• Contamination: coolant, oil or power steering fluid (on other models) quickly degrades belt rubber, replace the belt once leaks are fixed.

When replacement time comes, use a quality EPDM multi‑rib belt and inspect the tensioner and idler pulleys. A noisy or wobbly pulley will chew through a fresh belt in no time, so swap suspect components together. Follow the under‑bonnet routing diagram, unload the tensioner carefully, seat all ribs squarely in the pulley grooves, then recheck alignment after a short test drive. A quick re‑inspection in a week or two is a good belt‑and‑braces move.

If the battery warning lamp flickers, A/C drops off at idle, or there’s a brief squeal on cold starts, a worn or loose drive belt is a top suspect. Confirm the exact belt spec by VIN when ordering, as supplier variations can change length by a few millimetres.

Does the 2018 Impreza have a timing belt or a chain?

It has a timing chain. The chain handles valve timing inside the engine, while a separate serpentine (accessory) belt runs the alternator and A/C compressor.

How often should the drive belt be replaced on a 2018 Impreza?

It’s condition‑based. Have it checked at each service, replace it if there are cracks, glazing, fraying, noise, or contamination. Many owners see replacement somewhere around 100,000–150,000 km in local conditions.

What size belt does the 2018 Impreza use?

It uses a single multi‑rib serpentine belt. Exact length can vary with production updates and component suppliers, so confirm by VIN or by matching the old belt before purchase.