Life expectancy of OHC timing belts?

[Ace]

I'm interested to hear of personal experiences with timing belt failures. Here is my story:

I have a 1983 Tercel 4wd DLX wagon which I bought in 1984 with under 15,000 miles. It currently has 148,792 miles, relatively low mileage for a 41-year-old car. Standard 3AC engine.

I replaced the original non-failed timing belt in 1994 at 75,205 miles, 11 years age. It didn't appear to be obviously worn, as I recall.

The replacement timing belt failed in 2023 at 147,550 vehicle miles, 72,345 miles and 19 years since belt replacement. Fortunately there was no apparent valve damage with non-interference engine, and it happened to fail just as I was leaving my house instead of stranding me out on the road somewhere. At this time I replaced the broken timing belt and also the belt idler/tensioner pulley. I also replaced the non-failed water pump at this time because it is basically underneath the timing belt and I already had things apart. Total parts cost was under $100. I did the work myself, 'free' labor. My new timing belt is Gates brand, if anyone wants to comment on brand names. This is not a place to economize with cheaper unknown brands! Labor cost dwarfs parts cost!

When my timing belt failed last year the engine immediately died, and the engine cranked with virtually no compression. This had never happened to me before but I guessed right away that the timing belt had broke. Easily verified by looking in the engine oil fill hole while someone cranks the engine and you see that the valves aren't moving.

Some online research suggests that timing belts are generally good for 60K to 100K miles. Age is also a factor; the rubber deteriorates.

I'd like to know how much mileage other operators of OHC engines are getting out of their timing belts. Also, what parts and labor charges have car owners encountered if a garage does a timing belt replacement?

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[dlb]

I haven't had a timing belt fail but I have seen them visibly worn to the point I replace them preventatively. The last one I replaced was cracked and brittle throughout so it was a no-brainer.

[Mattel]

I get them done every 100,000kms or 10years whatever comes first.

[Nordical25]

I try to inspect them visually sometimes. I have had my first 3A engine since 2005 in very irregular usage. It has its timing belt probably from 1990's and I have never replaced it.

But I have replaced my timing belt in my two best condition cars due to higher running hours during last 4 years.

Therefore I do only visual check on engines that do not run regularly and 5-10 year rule to regularly running engines.

So lifetime expectancy is dependant both on age and on running hours.