How long do timing belts really last?

I see two Subaru recommendations for 1998 vehicles (see link below). One for California specified vehicles, another for Federal. They differ as one says change at 60k, the other 105k. Try to check what specifications apply to your vehicle.

Timing belt replacement recommendations are basically statistically based, or determined. At 60k, on average, only a very small number of belts should fail. I would have no problems taking a chance and extending the change interval by 10%, especially if you have a non-interference engine (the 2,2L supposedly is) as, statistically, there should not be a great increase in failures for this slightly longer interval.

But if the car has seen adverse conditions, hot, humid, or very cold environments, not been garaged, or has been driven hard, I would change per specifications. Why risk being stranded, and pay towing costs etc? Under these conditions, if I were really short on cash I'd maybe stretch it 5%, not much more.

Now, mind you, this is all coming from a person that has preventatively replaced his timing chain on a GM V6 engine at 135k miles. It was only very slightly loose but my schedule required long distance high-speed trips over remote mountain passes and I dare not being stranded, so I did it.

M.J.

The newer ones are good for 105k. My 94 Trooper said 60k change. Most sources suggested waiting until 90k as belt breakage was extremely rare. I waited until 90k+ and then did it.

[...]

this part I do not get. the same car - cal 60K interval, other states

105K interval. Any clue?

Andy

On most Subaru models for the last decade, timing belts can safely be expected to last around 105K miles. After that, you start to take your chances. My 1998 Outback Sport (totalled last year in an accident) had a recommended replacement interval in the owner's manual of 82K miles. My mechanic (an independent Subaru specialist), my dealer's head mechanic, and a bunch of Subaru owners all concurred that this was at least 20K too soon to worry about it, and in fact the next year's model recommended 105K.

Double-check with a real expert, but you'll find this is right. :-)

California specs differ from Federal with respect to emissions controls as California has stricter emissions laws. Form what I've read this means a few less ponies as exhaust is more restricted due to more emission controls. Now how does this relate to the 60k vs 105k timing belt interval I have no idea.

My speculation is they're all good for 105k, but because Californians drive much much more than the rest of the nation, Subaru gets California drivers off the hook, while drivers in other states help pad dealer profits by changing their belts more often than really needed. This is just a conspiratorial-type hypothesis on my part. There may be valid reasons for the difference.

M.J.

My 2004 Forester (2.5 SOHC) has a "camshaft drive belt" change interval of

168,000km (104,393miles).

Hi,

Very hard to say...

But experience w/ earlier EA-82 belts tells me a Subaru OEM belt will generally last longer than an aftermarket part. Maybe by a bunch?

W/ the EA-82s, the book recommendation was originally 60k miles. Later, I saw on the SOA website it had been cut to approx 50k miles. I asked my dealer parts guy about this, and he told me it was a CYA move as so many people were breaking belts BEFORE the 60k on these engines.

My anecdotal experience mirrored what he told me: I had a "name brand" aftermarket belt break at 52k miles, stranding me in 108 deg heat. Not fun. OTOH, when I've changed out OEM belts, they looked perfect at 60k mi.

I don't know if newer single belt designs use a generally more robust belt than earlier two belt designs, or if there's a Calif. specific belt using better materials, but either possibility COULD be part of the higher mileage recommendations. To support the "better materials" idea, the earliest VW water-cooled engines had NO change recommendation in the book (you WERE supposed to inspect and adjust at some interval--30k miles IIRC.) Rumor had it they used steel "cords" instead of the fabric we see today. I had the original belt on a Rabbit I bought new and sold w/ 189k miles, and it was just fine.

There's no "non-economic" (or "non-conspiratorial", if you wish?) reason a belt can't be made that can be expected to go EASILY 150k miles IMO. In the meantime, you might ask your dealer if the "Calif" and "49 state" cars use the same belt. If they do, I'd be comfortable extending the change interval IF you put miles on like we do out here (on average, 60k miles in most areas may well translate into 105k miles in Calif--TIME wise. Time's always an enemy regardless of miles.) If not, I'd ask about purchasing a "Calif" belt next time...

Rick C

It depends. :-)

Time, mileage, and environment are the main variables.

Inspecting the belt for cracks and wear would be something you'd want to do before deciding to extend. But with an interference engine, always weigh the deferred maintenance against the holy hell you'll introduce if that thing lets go.

I had one timing belt go on me on a Honda civic. The engine shouldn't have had more than 60k on it but this was the 2nd engine in teh car, and the unknown was how long and where the engine sat on a pallette outside of a vehicle. Why the indepenendent didn't change the damn belt when installing the engine, I'll never know. I was 19 and very ignorant about automotive issues back then. The original engine had died apparently since the 2nd or first owner of the car had it in a front end collision apaprently, and some antifreeze mixing with the oil apparently conspired to wear the rings down to nothing, and dropping a used engine from japan in it was cheaper than fixing the rest of the lot. At least that was the best theory my mechanic could come up with. After teh 2nd engine lost that timing belt, we patched it back together and traded it in on another vehicle. Upper engine was in good shape but lord knows what happened to the lower engine after that thing broke.

At least I have 4 slightly bent exhaust valves as paperweights to tell timing belt stories.

Best Regards,

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA

On Mon, 14 Jan 2008 22:15:21 -0500, Erasmus wrote (in article ):

My wife's '99 Forester (bought new in the fall of '98) has less than 50K miles on it and a recommended timing belt change interval of 105,000 miles or

105 months. The car was coming up on 105 months last fall, and I was undecided whether to change the belt based on the age criterion despite the low mileage.

One of our sons is a service advisor at an independent garage in Park City, Utah, where there are lots of Subarus, so I asked his opinion.

With less than 50,000 miles in nine years (including one trip from Virginia to Utah and back) it's obvious that this car makes mostly short trips. Indeed, almost all of her trips are less than ten miles, many less than two miles one way, a lot of them just a half-mile to another son's house. The greatest strain on the belt comes at starting, when it's jerked into action, so this belt has seen more wear than the typical belt at 50,000 miles. Therefore he suggested I go ahead and change it, so I did.

If your car makes mostly long trips, you may be safe in stretching the change interval somewhat.

Most engines have a place where you can inspect the timing belt, either thru a hole in the cover, or a section of cover that is easily removable.

This doesn't tell the whole story, tho; there's more to the system than just the belt. Idler pulleys, belt tensioner, waterpump, all need to be inspected, as any failure here will have pretty much the same result as a belt failure.

I'd suggest that the idlers are equally as weak of a link as the belt it's self, maybe even more so. And how long do _they_ last? At the

105K service (actually closer to 115K), the belt on my wife's Forester still looked pretty good. None of the idlers were very good, tho, and one was pretty rough; might have made it another 20-30K, might not.

No worries, tho, I was already planning on replacing everything; timing belt, accessory belts, waterpump, tensioner, idlers, thermostat, and radiator hoses. Minimal extra work, maximum peace of mind for the missus.

How much is your (or your spouses) peace of mind worth? You decide :-)

ByeBye! S.

Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101

I wouldn't take a chance, but it depends on your car. I think the older engines would just quit and coast to a stop, as the pistons can't hit the valves. The later models are all subject to piston/valve damage when the belt breaks, not only leaving you with a tow charge but a large repair bill as well.

Who knows? I have an old 91 Ford Tempo that had the timing belt changed at around 60K and now at over 200K it hasn't broken. Actually the only real problem I ever had with that car was the starter. The first starter died just inside the waranty and it's been through one every 2-3 years ever since.

Thanks to all who responded. I guess I'll just go ahead and do it "on schedule."