Timing Belt: On schedule, or when it fails? (gaskets, valve, chip)
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I've had to replace four timing belts, when they failed. The failure always came when idling or when starting cold---I just tow it to a shop and pay the bill. All were in cars with well over 100K on them.
There are horror stories about belts that failed and pretty well totalled the engine---how rare is that? On the other hand, slightly less horrible, getting it done at scheduled interval, and having the job botched.
When I buy a used car, I never have any idea whether the Tbelt has ever been changed or not. When you pay $2,000 for a car, who cares?
So, the question is, should one replace the belt every 80K (at $400 a pop) or just wait until one's luck runs out?
I knew some guys in a Subaru shop, who automatically replace the OE belt in all Subarus they work on. (They buy, fix and sell a lot of used Subarus.) They said the aftermarket belts last forever, and not one has ever come back failed. Is this typical of replacement belts?
Not all belts are at an 80k interval. Some are as low as 60, some over 100.
If the shop would botch the job at the scheduled interval, then chances are they'll be totally lost if the belt has already broken. And depending on the vehicle, you can do a lot of damage if the belt breaks or jumps a tooth or two. That's known as an interference engine.
You can tell if a timing belt has been replaced if you know what to look for.
As far as your question, just how lucky do you feel?
Timing belts are considered preventative maintenance. Y'know - so you can PREVENT mishaps in the future.
As for rarity ... it's rarer these days engines to be non-interference, which some older cars were. A broken timing belt means the pistons are crashing into the valves, meaning a head rebuild at the very minimum, to an engine rebuild at the worse case. Neither are going to be cheap ...
$400 for 80,000 miles means it costs a half-cent a mile - hardly a budget buster.
As for whether it's been done when buying a used car ... ask for proof. If it was done, the previous owner would have receipts; if it wasn't or unknown, then you have a bargaining chip now.
It really depends on the car. Sometimes the failure is with the tensioners and not the belt itself. Some factory belts and tensioners are very durable with little issues. Others are very problematic. In certain cars aftermarket belts and tensioners are a lot stronger and more durable, it all depends on the design.
The issue is if the belt fails while the engine is under load and moving down the road, there is a very high chance that the valves will hit the pistons and this can cause extensive damage that is far costlier than preventatively replacing the timing belt.
I know in the VW scene, timing belt replacements are often recommended to be done preventatively and before they are manufacturer recommended. If people are extensively modding the car, they often replace the belt then as well as the water pump, which is another failure prone VW part that the aftermarket provides a better piece for. Subaru guy's are usually the same way, though Subaru belts are a little more robust. Head gaskets tended to be more of an issue on those, so people would replace the belts proactively when they had the gaskets done.
I guess in your situation it would all come down to how long you want to keep the car, how much the t-belt would cost and whether or not you really care. If you treat the $2k cars as throw aways, then I wouldn't bother. If you generally keep them a while then doing a t-belt replacement is probably a good idea. Again, it all comes down to the specific car.
PS Sometimes a shop (particularly if it was dealer installed) will paint a date/mileage somewhere on the front cover to record when the t-belt was done.
If you have a non interference engine and you don't care if you're stranded at the side of the road, then go ahead and wait for it to snap, if it's an interference engine I wouldn't recommend it, unless you're looking for a good excuse for throwing a newer/different engine in there.
So, the question is, should one replace the belt every 80K (at $400 a pop) or just wait until one's luck runs out?
You could be in one heck of a bad situation when that timing belt goes, think rain,cold.blizzard, extreme heatwave, medical emergency,10 mile walk to nearest service area, wrong side of town late at night
.And very expensive engine repairs if its an interferance setup..
Throw the $400 at it and call it a late car payment.
This is not a question of chance - if you have an interferance engine, and break the belt or get it sufficiently wrong when changing the belt, Mr. Valve will have a close encounter of the expensive kind with Mr. Piston. For example, Subaru 2.2 and 2.5 flat 4 engines after 97 are interferance, before that they are not. My 8V 1.7 VW engine is not interferance, a 16V of the same general 1980s vintage is.
IIRC the OP is retired - if you have a non-interferance design, have other cars to drive, and would not be upset by the car quitting suddenly and needing a tow to a shop - you can "fix it when it breaks".
If you have an interferance design, and this is more common as you get into later model cars, do it on time or ahead of time - as I always point out, all miles are not created equal, I have seen broken TB on BMW "Kliensechs" small 6-cylinder (E30 325i, etc.) at around 50K although the factory interval is 60K. These cars were driven mostly in town, lots of A/C use with the car not moving, etc.
If you are reasonably handy, learn to DIY. Many TB jobs don't require much in the way of special tools, it's just a goodly volume of work. If you have a decent garage, a shop manual, and other cars to drive so you don't feel too much time pressure, DIY. Having said that there are some like most Honda that require removing a big crankshaft nut, that's on to mega-torque, these will defeat all but the most elite of DIY mechanics.
So, I google my current car ('01 Sentra) and I find that it has a non-interference engine, and a timing chain, not a belt, which generally lasts virtually the life of the engine. Good news?
Since most other carmakers are not building their engines with unbreakable timing chains that do no damage if they do break, what's the down side?
Pretty much, I wouldn't worry about it personally. The chains can stretch over time and even break, but given that it's a non-interference engine, it won't really grenade anything if it does go. Up to you, like others have said, if you can afford the downtime and don't mind risking getting stuck, there's really no need to change it.
Chains do break. And there's more to it than just a chain and two gears. Tensioners and guides are also used and those are usually where the problem starts.
The biggest downside to a broken chain is all the metal and plastic pieces that end up in the oil pan when a chain lets go.
As a rule, you leave a timing chain alone unless there's a problem with it like excessive noise. Or it breaks.
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