Mitsubishi Evo X Metal tensioner pulley upgrade kit

Evo X Metal Tensioner Upgrade with Metal Idler Pulleys

Our Evo X metal tensioner upgrade replaces the plastic tensioner and idler pulleys with metal pulleys on the Mitsubishi Lancer Evolution X 2.0-litre 4B11T engine. The upgrade kit includes a Contitech serpentine belt and a brass shim for the tensioner. All pulley bearings are NSK bearings.

Why replace the original plastic pulleys?

It is a well-known problem with the Mitsubishi Evo X that its original plastic idler and tensioner pulleys are prone to wear. This can cause the serpentine belt to wear and split. Once damaged, the belt may come off.

The problem is not always the belt itself. A worn pulley can guide the belt away from its correct position. Replacing the belt alone may leave the cause of the damage in place. In MotoIQ's documented Evo X repair, a replacement belt still moved off the pulleys until the worn plastic idlers were replaced with metal ones.

This makes belt replacement a useful time to inspect the idler pulleys and tensioner pulley together. Our kit offers the plastic-to-metal pulley upgrade with a new belt for the same job.

What Is Included?

• Metal idler pulleys to replace the original plastic pulleys.
• Metal tensioner pulley for the auxiliary belt drive.
• Contitech serpentine belt.
• Brass tensioner shim.
• NSK bearings in all supplied pulleys.

This is an auxiliary / serpentine belt pulley upgrade. It does not replace the engine's timing chain or timing-chain tensioner.

Mitsubishi Evo X Models and Years

For the Mitsubishi Lancer Evolution X / Evo 10 (CZ4A) with the 2.0-litre turbocharged 4B11T petrol engine and the standard auxiliary belt arrangement.

• Evo X GSR: 2008–2015 model range.
• Evo X MR: 2008–2015 model range, including TC-SST versions.

Model availability varies by country. For early 2007 Japanese imports, UK FQ versions, RS models or cars with altered accessories or belt routing, please contact us with the vehicle details before ordering so we can confirm the complete kit and belt application.

The condition of the pulleys matters as well as the year. A car may already have replacement metal pulleys fitted. Inspect the existing arrangement before ordering. Do not assume this complete kit fits other Mitsubishi models simply because they use a related 4B1 engine.

Useful Checks Before Replacing the Belt

• Look for frayed edges or a belt splitting lengthways.
• Check for uneven wear on the plastic pulley surfaces.
• Check whether the belt sits correctly on every pulley.
• Inspect the tensioner mechanism as well as its pulley. A metal pulley will not restore a worn or faulty tensioner mechanism.

A detached auxiliary belt can lead to loss of charging, overheating and loss of hydraulic power steering assistance. Mitsubishi documented these risks in its drive-belt recall information for certain 2008–2011 Lancer Evolution vehicles in the US and Canada. That recall coverage is separate from this kit's fitment. Recall status should be checked by VIN with Mitsubishi.

Fitting Notes for the Metal Tensioner Pulley

Brass shim and pulley clearance

The brass shim for the tensioner is included in the set. The tensioner pulley conversion needs clearance between the metal pulley and the tensioner body. Use the supplied shim as intended and check that the pulley turns freely without rubbing. Check belt alignment before putting the car back into use.

Remove the pulley before fitting the tensioner assembly

Please note that you need to take the tensioner pulley off before fitting the tensioner assembly. There is not enough room to fit the tensioner with its metal pulley attached.

The tensioner pulley retaining bolt has a reverse (left-hand) thread. Turn it clockwise — to the right — to loosen it. This refers to removing the pulley bolt. Releasing spring tension to remove the belt is a separate operation. Follow the workshop procedure for your vehicle.

Pulley Upgrade Photos