Time To Take A Belt To It 

Timing belts have been around a long time, and the amount of production cars with one number in the millions.  So there’s a lot of potential for a needed repair or a potential failure with that many cars on the road.  This is one of those items that need to be checked out at the prescribed time (according to the manufacturer’s specifications) and verified as to the condition of the belt and its corresponding components.
It’s not uncommon these days to not only have a timing belt to change but also the water pump, since a lot of manufacturer’s have gone to using the timing belt to turn the water pump as well.  That also means there are other components that are involved that need to be changed, such as the tensioner pulleys, idler pulleys, pretensioner, springs, and in some cases a couple of seals or gaskets need to be replaced.
Not to forget the varied types of timing belt setups, single, dual, or quad cam, dual timing belt engines, balancer shaft belts that are separate from the timing belt,(but need the exact same attention) and several other variety of belt configurations.  There’s also the occasional manufacturer that puts their crank shaft sensor behind the timing belt which leads to even more issues when replacing the timing belt. (Make sure you return all the hold down straps and fasteners back into place to avoid any part of the sensor harness, wiring, or the sensor itself from coming in contact with the timing belt.)
But what we really need to know is how we can determine if the belt needs replaced.  Sure we can use the manufacturer’s recommended mileage/time as a way to know when it’s time.  But, in some cases engine wear, oil leaks, or a customer’s driving habits could lead to a quicker demise of the timing belt. Knowing the signs of a soon-to-fail timing belt might be the best news you could give to your customer.

Top Ten Reason to Replace the Timing Belt

Cracking - - Cracking is a good indicator of the age of the belt.  (The older the belt gets (and the amount of heat in the general area) break down the rubber composite material of the belt and cause it to dry out.)  Cracks running across the belt face can cause the belt to lose its ability to maintain the proper belt length. Cracks running lengthwise are extremely worse.  These cracks start to become elongated and eventually cause the belt to separate into several strips. 

Glazing - - Glazing is the shiny surface that you’ll see on the belt.  Glaze can come from a lot of different related problems, age, pulley wear, or a fluid getting onto the belt surface.  Not as serious as cracking but something you should tell your customer about.

Tooth Depth - - Tooth depth referees to the actual depth of the tooth contact area of the belt where it aligns to the cogged pulleys.  If debris builds up on either the pulleys or the belt grooves the likelihood of a belt slipping a tooth or more is very likely.  Examine the belt and the pulleys for any build up in these areas.

Belt Abrasions - - Abrasions can be caused by numerous things.  From debris getting inside the timing belt covers to the belt material itself. Abrasions can result in pits or pieces missing from the belt. 

Water or Oil Accumulation - - Oil leaks and coolant leaks not only can affect the life of the belt but also the overall operation of the belt.  A belt could slip under acceleration or start up; it could lead to glazing, tooth depth, and eventually cracking.  Solving the issue with the fluid leak would be a priority over replacing the belt, mainly because the new belt would end up in the same condition if the cause of the leak wasn’t addressed.

Cupping - - Cupping is a sign that a belt is either severally worn or someone has over tightened the belt.  The edges of the belt will be raised slightly or rolled up exposing the tooth side of the belt.  At this point the belt is not reusable… replace the belt. 

Fraying - - Fraying is a common occurrence to timing belts.  The first sign of fraying is the fluffy or powdery remains of the belt inside the timing belt covers.  Age, use, and simple belt fatigue are the usual causes. One thing to consider when you see indications of fraying is to examine for any tooth depth problem.  This is one of those times when you’ll see the debris pile up between the pulley teeth or the belt teeth. 

Pulley Alignment - - Pulley alignment may not be as clear to the eye at first, but look carefully at the wear pattern marks on the pulleys.  Normally there will be some indications of where the belt has been riding on the pulley surface.  If the belt isn’t in the same spot chances are a bearing or pulley could be worn and causing the belt to move to a new spot.  Sometimes, there may be bearing noise associated with this or even belt squeal. 

Belt Length - - The overall belt length isn’t something you can actually measure with the belt on the vehicle, but by using the other signs of belt failure you might be able to make a determination as to the length of the belt or if the belt has actually stretched. (I’m not a fan of the term “stretched” timing belts are designed and manufactured not to.) However, overall belt length changes as the belt teeth wear down or the material cracks, frays, etc…  A good indicator that the belt length has changed is to check the timing mark alignment.  If the marks are close, but still look as if they are off by perhaps a half a tooth chances are there is some wear on the belt causing the belt to be longer than when originally installed. 

Deterioration - - Time, temperature, debris, as well as engine condition can determine the amount of deterioration or the life span of a timing belt.  Things like a sticky valve on startup, or a seizing cam bearing can put an extra strain on an already weak belt.   Anytime there is any deterioration of the timing belt it’s a good time to suggest a new one.

Timing belt maintenance is really the key, knowing how to spot a potential problem before it’s a problem can not only save an engine from utter catastrophe but keep a smiling customer on the road. When you see any signs of wear or fatigue it’s definitely time to take a belt to it.

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