I had a timing belt replaced on our 2001 Civic last November at 100,000 miles. Then, recently looking over my service notes, I see that I actually had the timing belt replaced about 1 1/2 years earlier at 92,000 miles. Duh! Who doesn’t pay attention to these things?! My bad. Now, I imagine they recommended the work - both times - because of the mileage. But my question is, in the absence of a wide-awake customer who would question the recommendation, and a mechanic who might review the service history of the car, would a mechanic know by visual inspection that the timing belt doesn’t need to be replaced, if the one in the car is only 1 1/2 years (8,000 miles) old? In addition to increasing my own consumer awareness, I’m wondering if there’s anything unethical about the mechanic’s approach to the issue.
Generally you can’t really tell while the belt’s installed on the car. The trouble is that they tend to wear and crack along the inside ribs which are essentially impossible to inspect with the belt installed. I’ve had ones that looked perfectly fine from the outside but once I had them off the car were practically falling apart in my hands.
Once you actually have the belt off the car you could probably make a somewhat reasonable guess as to what kind of shape the belt is in, but it’d be kind of silly not to put a new one on with all the labor necessary to get to that point. It really is just a “replace at X mileage” item. It’s usually good practice to put a sticker or something under the hood to indicate the date/mileage it was last replaced.
Yep, exactly.
The timing belt isn’t the type of part that you just open a cover, replace the belt, and slap the cover back into place, and that’s it. The timing belt goes between the engine crankshaft and the camshaft, and spins the camshaft which opens and closes the valves that make the engine work, coordinating those valves with the engine pistons, which are attached to the crankshaft.
In order to change the timing belt, you need to remove the front cover off of the engine. But, on a modern car, you’ve got about 40 bizillion things attached to the front cover of the engine. The alternator, air conditioner’s compressor, power steering pump, and other things all are in your way. So, just to get to the timing belt, you need to do the same labor as replacing the alternator, replacing the AC compressor, replacing the power steering pump, belt tensioners, and a bunch of other stuff, and that’s just go get to the engine cover. Then you have to remove the engine cover and actually change out the belt. All of this labor is why just changing the timing belt is a bit costly.
On many cars, they’ll recommend changing the water pump when you change the timing belt, since you’ve just disassembled the entire engine to the point where changing out the water pump is just a minor addition to the work involved. If you don’t change out the water pump and it breaks later, then you have to repeat all of that labor just to get to it.
So yeah, if you just went through all of the labor to disassemble the front of the engine, it would be silly not to replace the belt while you are there, even if the belt did look almost brand new at that point.
Your mechanic didn’t do anything wrong.
If you want to see what your mechanic had to do, here’s a youtube video of a guy doing the job at home:
Note that this video is just part 1. It continues on to multiple videos. ETA: He doesn’t even get to the timing belt itself until the second half of the 3rd video.
What GreasyJack said.
Timing belts pretty much defy visual inspection. If it’s really close to new, with the writing on the outside surface not faded, or really old, with the outside surface cracking, you can tell something IF you’re trying to evaluate it*. Most of the time, though, a belt with 10,000 miles on it will appear about the same as one with 100,000 miles on it and you have to remove it to learn anything. On many engines the labor to get to that point is 85% of the cost of belt replacement, and even if the belt looks good there’s no way to know how much longer it will last if re-used. It’s pretty hard to make a case against installing a new belt.
*A mechanic instructed to replace a part for maintenance reasons isn’t looking to assess its condition. IF he were instructed to inspect it – which is virtually never done on a timing belt for the reasons mentioned above – he might have determined prior to removal that the belt was not due for replacement yet. But that still leaves the question of just how old is the belt (i.e., how long will it last now) and some money has already been spent removing timing belt cover(s) just to get eyes on the belt. I don’t see an ethical lapse here.
On preview, what engineer_comp_geek said.
Did you go to the same mechanic both times?
Everything said so far is true. The problem with timing belts is just what Gary T said; a belt with 10,000 miles won’t look much different than one with 100,000.
The real danger is that they tend to fail suddenly. Either they snap while the engine is running, or the crank sprocket shears a bunch of teeth off of the belt when you go to start the engine. And lord help you if it’s an interference engine.
I’m surprised you forgot you replaced the belt. Its an expensive job. Honda wants almost a thousand on my 2001 Civic. Of course, I can get it done for about 40% of that price. Dealers, you know.
I’ve replaced the timing belt on my 92 and 96 Accord four times now. The first time was a bitch. Last time I had it done in 2.5 hours with no lift.
I was not able to see any major difference between the old ones and the new belts. My uncle had to replace his engine due to a broken belt so I’ve never worried too much about the price. I got the whole kit including water pump online for 150 iirc.
I have a sticker on my belt cover with the date and mileage of the replacement. I thought that was standard, I guess the service advisor didn’t look for it or it was left off.
20-30 years ago the materials used in timing belts was different and as the belt got old you would see cracks in the back of the belt. Great big honkin cracks. Those belts you could eyeball the condition of.
Now a days the belts last 2-3 times as long but don’t show cracks.
No mechanic will bother to inspect a belt. If you have the work done by the same dealer and they recomended you change the belt based on mileage you may have some issue with the service writer. You vehicle records should indicate that it was allready changed. But only if all your work is done by the same shop. I would always review a trucks history before recomending replacing anything based on mieage.
My info shows a timing belt replacement interval of 110k miles. However, since in this case it’s more than ten years old, replacing it a couple years ago at 92k, or last year at 100k, is a reasonable thing to do. It’s replacing it both of those times that’s whacky. 
:smack:
If it was the same shop both times, and particularly if the shop suggested it in November rather than you requested it, I think the shop goofed. A sharp operation would have reviewed your file to get an idea of maintenance that might be due (which they could legitimately sell you, to your benefit and their delight), and also of maintenance done – which they’d better not try to sell. Even if done in all innocence, avoidable overselling of work gives the appearance that the shop is not honorable, and at least indicates they’re not on the ball looking out for your needs. If this is the case I’d talk to them and request some compensation.
If it was two different shops, then it looks like the responsibility falls on the car owner.
The Honda service writer at the dealer we bought the car from wanted to change the timing belt on our 2008 CR-V. I declined the service since that engine has a timing chain.
Speaking of the labor involved with timing belts/chains:
I had an '87 Accura Legend (coupe). Since the Accura was brand new ('87 was the first year of full importation and dealer network), there was a service manual in the trunk.
Just for giggles, I looked up the procedure to replace what they called a “chain” but was not metallic, just a toothed belt.
It specified completely disconnecting the engine, loosening the engine mounts, and lifting the engine by its hoist eye.
This was a transverse mount V6 which occupied just about every cubic inch of the compartment.
Are they all that nasty?
Can’t speak for all timing belts but they do seem to be tricky. There are nuts that are hard to remove, gears that need to be locked in place and in general an above level of care needs to be taken.
My last three automotive purchases are vehicles with timing chains. Why? Read above.
then the chain tensioner fails 
Timing chains are certainly not without their maintenance requirements and horror stories upon failure as well.
The old style timing chains on overhead valve American engines were simply an oval shape connected to two pulley gears. Newer dual overhead cam engines have chains that look like a big “W” and can be close to 7’ long. These chains have tensioners that keep the chain tight as it rotates around the collection of gears. These long chains have well over 100 links. If each link stretches just a fraction of an inch the chain will get some serious slack. The slacking chain then slaps the plastic tensioner arm and eventually causes a piece to break off. Many times the broken piece then jams between the chain and the gear teeth causing a sudden stop which grenades the engine.
Keep up on timing chain maintenance as well. The failure bite is just as bad as a belt.
Honda recommends replacing the timing belt every 100k. They also recommend replacing the water pump at the same time as most of the labor is the same. You should keep a record yourself of when this changing occurs, including the receipt, because even if you go to the same shop, they might not check the records, or check them correctly. My dealer insisted I hadn’t had mine changed at around 100k and I knew I had paid otherwise at the same dealer. A more experienced service writer found the record.
Having been the shop in question, (did the same job twice) I have cheerfully refunded any money paid no questions asked as it was my people that screwed up.
Then I have a long heart to heart discussion* with the employee(s) involved on the importance of reviewing the customer’s repair history before selling anything.
It’s funny how I have never had to have that conversation more than once with any one employee.
I guess my inner grumpyness comes through. 
*Also known as a come to Jesus meeting.
Although the difference there is that a bad timing chain usually gets noisy and/or causes performance issues due to sloppy valve timing long before anything truly engine-destroying happens. A timing belt usually gives you zero warning before it goes. That’s why timing belts are periodic maintenance items whereas timing chains generally aren’t, even if in some engines they tend to wear out pretty regularly (I’m looking at you, Toyota 22R.)