Timing Belt Service - Years vs Mileage

[tomsawyer]

Hey Everyone - I have an 03 LX w/ 110K. I had purchased the truck w/ 98k and the 90k service had already been completed. Between having been traded in by the original owner and finally getting into my hands, I haven't really been putting a lot of mileage on the truck. I took the truck in for 105k service at the dealer (I just wanted them to do a complete once over on the truck and advise of anything) and the service advisor pointed out that I should think about the TB service, not from a mileage standpoint but from a time standpoint. Is there a time component to the TB service or is it strictly mileage?

Thanks to all who answer.

 

[DirtDawg]

90k or 7 years, whichever comes first. Official Toyota interval.

 

[BillZ260]

Still have yet to see many if any belt failures. I'm sure they are out there. Of the (2) 4.7 belts that I have changed at ~110K miles, one was about 7 years old, and the most recent was 15 years old, the belts looked great. I'm leaning towards 150+ K miles rather than 90.

 

[Gandy]

I’m currently sitting at the dealership. Truck has 94k on it and they REALLY want me to do the timing/water kit. Begging me. They’re telling All kinds of horror stories. I know that on my LExus LS400 My mechanic was very honest with me and said he had never seen one fail. What is the failure rate of an LX 470 timing belt? Who has had a failure? And what mileage where you at?

 

[flintknapper]

I’m currently sitting at the dealership. Truck has 94k on it and they REALLY want me to do the timing/water kit. Begging me. They’re telling All kinds of horror stories. I know that on my LExus LS400 My mechanic was very honest with me and said he had never seen one fail. What is the failure rate of an LX 470 timing belt? Who has had a failure? And what mileage where you at?

The timing belts themselves almost never fail. It is a pulley, water pump or tensioner that will eventually seize up and take out the belt.

That said, the timing belt is made partially of a rubber compound, so it has a 'life' to it even if seldom used. Not unlike tires 'dry rotting'. Hence Toyota's recommendation to change at 90K/7 years. They have to consider the very WORST conditions the engine might be subject to as well.

 

[white_lx]

Here is another data point for you:

At 64k miles and 11 years my belt looked really good. I was a bit concerned because of the 7 year interval, so replaced it despite only having 64k miles at the time. Granted this is a pretty mild climate, with few very hot days.

As per other posters, the ancillaries are more important than the belt itself. If you decide on a service, make sure everything gets replaced: water pump, tensioner, two idlers and belt. If these parts were not replaced at the previous service (does anyone only replace the belt only?), then it would be more important to carry out the 2nd service at the correct time.

 

[biggus]

I'd go 10 years on a timing belt and wouldn't think twice about it.

 

[97 AZ LC]

As per other posters, the ancillaries are more important than the belt itself. If you decide on a service, make sure everything gets replaced: water pump, tensioner, two idlers and belt. If these parts were not replaced at the previous service (does anyone only replace the belt only?), then it would be more important to carry out the 2nd service at the correct time.

The factory does not have an interval on the water pump. The factory clearly says only to inspect the water pump when replacing the timing belt. The million mile Tundra had exactly one water pump replacement in a million miles. The notion that the water pump is replaced every 90k came from dealers that like the money. For a DIYer it's not that hard to go in and do the water pump if and when it fails.

 

[SouthJerseyJim]

I was a mechanic for 10 years and have seen my share of tbelts and tbelt failures. My own 2000 LC with 109K when I did the tbelt I got it just in time. It was cracked at every rib. I think time over mileage is accurate. Truck sits a lot and the years go by the belt weathers. Use it a lot and I believe it will last longer. Its not a lot of work to pull a T belt cover and do a little inspection every 10k or so after 90K to keep an eye on wear. Tensioners I rarely saw fail but it does happen. They can leak hydrolic fluid and get weak overtime. Pulleys will usual make noise and give you a clue before they go bad. Water pumps that arent leaking or whining are fine to do every tbelt also since your already in there.

 

[flintknapper]

The factory does not have an interval on the water pump. The factory clearly says only to inspect the water pump when replacing the timing belt. The million mile Tundra had exactly one water pump replacement in a million miles. The notion that the water pump is replaced every 90k came from dealers that like the money. For a DIYer it's not that hard to go in and do the water pump if and when it fails.

Personally, I think the 90K recommendation is a bit 'early' for the average owner. I'd wager most could safely go 150K....BUT environment and usage of each vehicle can vary widely.

In any case...a new Aisin Water Pump can be had (shipped) for $80-$95 bucks. The cost or effort to go back in a second time simply isn't worth it, were one to fail.

There are very complete 'kits' available these days (Timing Belt, Pulleys, Tensioner, Water Pump, Crank and Cam seals, serpentine belt) for quite reasonable prices. When mine is due again...it will be getting 'everything' again, but not until I've put 150K on the last change.

 

[97 AZ LC]

Personally, I think the 90K recommendation is a bit 'early' for the average owner. I'd wager most could safely go 150K....BUT environment and usage of each vehicle can vary widely.

In any case...a new Aisin Water Pump can be had (shipped) for $80-$95 bucks. The cost or effort to go back in a second time simply isn't worth it, were one to fail.

There are very complete 'kits' available these days (Timing Belt, Pulleys, Tensioner, Water Pump, Crank and Cam seals, serpentine belt) for quite reasonable prices. When mine is due again...it will be getting 'everything' again, but not until I've put 150K on the last change.

It sounds reasonable to do the water pump every time but still there's the question of why the factory isn't on board. Is it because they know that water pumps outlast timing belts by a factor or 3 or 4 or 5 as apparently with the million mile Trundra. It makes sense to replace it to avoid having to "go in again" before the next timing belt service. But does it make sense to replace 4 or 5 water pumps unnecessarily and prematurely to avoid having to "go in again"once? Water pump failures tend to be very benign events - a little noise, a little seepage, no harm to anything. It's understandable that dealers like it but I'm still wondering why Toyota isn't on board?

 

[cwmoser]

My 2002 LX470 with 40K miles is 16 years old.
Its always been garaged and driven easily.
I really am not anxious to replace the Timing Belt yet.
If I hear the water pump squeaking or leaking then I will.

 

[flintknapper]

It sounds reasonable to do the water pump every time but still there's the question of why the factory isn't on board. Is it because they know that water pumps outlast timing belts by a factor or 3 or 4 or 5 as apparently with the million mile Tundra.

I'm sure the 'expectation' is that a water pump (usually fairly reliable) will have a greater service life than the Timing Belt which is subject to different stresses and made from material that literally has a shelf life. But I wouldn't hold the 'million mile Tundra' up as an example. We all know that is quite the anomaly and NOT the expected design life of either the engine or its external components.


It makes sense to replace it to avoid having to "go in again" before the next timing belt service. But does it make sense to replace 4 or 5 water pumps unnecessarily and prematurely to avoid having to "go in again"once?

The trouble I have with this argument is that it assumes the Water Pump is designed and expected to last 400K-500K miles (if belts are changed every 100K). But I concede IF timing belts are changed at 90K intervals...then also replacing the Water Pump (from a perspective of 'need' VS. 'prevention' due to the possibility of early failure) is likely an imbalance. I don't intend to follow those intervals.

Personally, I will be replacing all components (TB, Water Pump, Pulleys, Tensioner, checking cam seals, etc) at 150K mile intervals, but that is due the the environment in which I live and the relatively light service asked of my vehicle.

IF the Water Pump were right out in the Bald Ass Open as with my 80 Series ...then yes...I'd leave it for sure.

But it isn't. Nor is the Starter (up under the intake manifold). To me....it just makes sense to NOT wait until they fail to replace/repair IF you are already in there for other service AND the part has appreciable use/wear already.


Water pump failures tend to be very benign events - a little noise, a little seepage, no harm to anything.

Agreed. Outright failures (no warning or symptoms) would be a rare event. Typically Water Pump failures manifest as a leak. However...owing to the location of the water pump and the several points at which it 'could' leak...it might allow coolant to drip down on the timing belt or infiltrate bearings that are no longer well sealed.

You won't see 'leakage' until it has made its way from the Water Pump all the way down the front of the engine and out the weep hole in the cover just behind the Balancer. Same thing with engine oil leaking from Cam Seals.

It's understandable that dealers like it but I'm still wondering why Toyota isn't on board?

Couldn't say. But admittedly I am confounded by some of the things 'Toyota' does and completely in agreement with others.

Thank You for your thoughts on the subject. It gives us all something to chew on with respect to vehicle maintenance.

^^^^^^ Expand for replies.

 

[Spike555]

Here is my $.02 on this...Since rubber does age why is there no service interval for the coolant hoses? Those are just as critical as the timing belt.
Timing belt breaks and you're stranded, radiator hose blows and you're stranded, so why replace a timing belt every 7yrs but not the coolant hoses?
How many of you have the original coolant hoses? I know I do.

You cannot tell the condition of any belt by the number of crack's in it, cracks are normal and means next to nothing.
The belts are either steel or nylon belted just like tires so the likely hood of a belt just breaking due to age is all but never going to happen.

I never replace serpentine belts until they start to squeal and glaze over, once glazed they are done. Serpentine belts only go bad when a pulley seizes or a tensioner breaks. These belts always give warning to a problem because they start to squeal on start up or when under load (a/c, high alternator load etc) and that means something is not right, either tensioner is tired or a pulley is adding strain, run this way to long and the belt glazes over, pulley seizes or tensioner breaks and the belt gets eaten, otherwise there is no service interval for a serpentine belt.

If you are doing your under hood check like you're supposed to once a week you will notice any coolant loss before it becomes a problem. Even if you do not see a leak, you will see the overflow bottle is not where it was last week, same with brake fluid and power steering fluid, and of course motor oil.

I think it is reasonable to replace the water pump every other timing belt service IF you are taking care of it, that means replacing the coolant before it wears out and looses it's lubricating properties.
But I am not against replacing it every timing belt service because you are in there and it is cheap. One and done kinda thing.
Remember, engine coolant does more than remove heat and protect against freezing, it also provides corrosion resistance and lubricates the waterpump, if you neglect the coolant you are looking for trouble.
Long life coolant is only good for 5yrs or 150,000 miles, I bet most of you go by miles and not years.
Personally I do not use OE coolant, I use cheap universal coolant and drain and fill every 2yrs no matter the miles, it's only $8/gal so it's cheap insurance.

A timing belt will not squeal because it has teeth, and it's behind a cover and the fan and other pulleys so you won't hear it anyway.

My personal preference is timing gears, but those are a thing of the past.