Timing Belt Components

A Belt, Not a Chain — and That Changes Everything

This is the single most important difference between the 5VZ and the four-cylinder engines we build.

The 22R, 2RZ and 3RZ run a timing chain, which is designed to last the life of the engine. The 5VZ runs a rubber toothed belt, which is a scheduled replacement item. It does not get noisy first. It does not warn you. It reaches the end of its service life and it breaks.

If you have bought a 5VZ truck and cannot prove when the belt was last done, do it now. The cost of the job is a small fraction of the cost of finding out the hard way.

Buy the Kit, Not Just the Belt

The timing belt kit is the right way to do this job, and the reasoning is the same as it is for a chain: the belt is not the only thing that has aged.

The tensioner and idler bearings have spun exactly as many miles as the belt has. Fitting a new belt onto tired bearings means the new belt fails early or runs on a bearing that is about to seize — and you will have paid the labour twice.

The belt on its own is available if you are replacing only the belt as part of a larger job where the other parts are already new.

Tensioner or Adjuster? Both, and They Are Different Parts

This catches people out, so it is worth being precise:

• The mechanical tensioner is the pulley the belt runs against.
• The hydraulic adjuster is the damper that applies tension to it.

They are two separate components and both wear. A hydraulic adjuster that has lost its damping lets the belt slap, which is how teeth get rounded off. If the belt is coming off, replace both.

The Cover

The timing belt cover keeps road debris, water and oil off the belt. It sounds cosmetic and it is not — oil contamination destroys a rubber belt, and a cracked or missing cover is a slow way to ruin a new one. If yours is broken, replace it with the belt.

Do These at the Same Time

A timing belt job opens up access that is expensive to buy twice. While you are in there:

• Water pump. On this engine it is driven by the timing belt, which makes it the classic do-it-now part — and there are two versions, with a cooler tube and without. Check which yours takes. See Cooling.
• Front crankshaft seal. The oil pump crankshaft seal is right there and it is what leaks oil onto a new belt if it is left. If the crank has worn a groove, the Seal Saver sleeve is what stops a new seal leaking straight away.
• Harmonic balancer. The elastomer deteriorates with age — see Pistons, Rods & Crankshafts.

If You Have Just Bought the Truck

Our honest recommendation: unless you have a receipt for the belt, assume it is due. Do the belt, the tensioner, the hydraulic adjuster, the water pump and the front seal in one visit. It is a single labour charge and it takes the whole front of the engine off your list of worries for a long time.

Tell us the year and mileage and we will list exactly what you need for your truck.