OK, I am pitching this for opinions. There are at least two professionals on this forum with the right experience to let me know the answers - but I'm interested in opinions in any case.

So: I am running, and succesfully maintaining a 12-year old car that is still in excellent condition. I budget for repairs where possible, based on what I see in my service schedule. However: there are some items that are just not covered.

So, the question is: what is the serviceable lifetime of the following, and when should they be replaced? Bear in mind here that if I am going to replace these items, I have to do it now before the statutory EU service parts requirements for the car expires this year.

The items in question:

- the exhaust gas lambda sensor
- the exhaust catalyst
- the driver airbag
- the seatbelts and mechanisms
- the unipoint injector (petrol) in the in the injector body.

The car is 12 years old, and has covered 295,000+ km, and has been regularly serviced according to the service schedule. It shows the following symptoms:

- rich mixture on shutoff (injector? lambda?)
- slowly increasing fuel consumption along with a sooty exhaust (no oil burn, oil colour still good)
- slight dropoff in acceleration/overall performance.

I am aware that you could chalk up some of this to;

- worn rings (but this would go with increased oil consumption - currently zero)
- worn bores (ditto)
- incorrect valve clearances (about to be done - bucket and shim)

I'm interested in your opinions!

I'm not a car expert, but I aspire to be. I try to fix more and more as I have problems (mostly with my 13 year old Subaru).

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- the exhaust catalyst

I would say 10 to 15 years based on experience with my 1993 Trooper. It bit the dust at 10 years. Not becauase of rust... the car was failing emissions testing.

The one on my Subaru lasted 12 years before I replaced it, but it was still good. I just had a custom exhaust built for it. Also, I'm not sure how the emissions test in NY works, but I know they can't do the dynamometer tests on AWD cars.

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- the driver airbag

In NY (and probably the US), this is not required once the car is sold as new. Many of my friends just put aftermarket steering wheels on their cars when the airbag light eventually comes on. Of all the cars I've had, I think all of them recommend having the dealer check the airbag every 10 years.

That's all the info I can contribute...

Oh yeah, in the US, manufacturers have to make parts for 10 years after the last model year. Subaru of America already forgot they sold the SVX here since many parts are stocked only in Japan. You often have to wait to get parts (even OEM radiator caps!). I hate to see what will happen in 2008 when they don't even have to make parts anymore!

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statutory EU service parts requirements for the car expires this year

Rob, can you explain this in a bit more detail?

As for a non-prefessional opinion; I'd persume an injector with ~300k km would have a less the perfect spray pattern, in part due to ware & tear but also so carbon & crap build up. It might by worth trying one of those injector cleaner additives to clean out the carbon. This would in my experience (wife's '97 Corolla with ~233k km) fuel consumption & preformance.

On Saabs it seems to come on whenever. I know other lights on cars I've had (like oxygen sensor) come on at a set milage. It may be the same deal on your Honda. Usually there is a switch in a really awkward place you can hit to reset the light. I'm sure you can find where it might be on the internet. On my Sidekick it was under the speaker in the dash, on Troopers it's behind the gauge cluster and on my Cadillac I think you can clear codes through the climate control buttons.

Instructions here

what is the serviceable lifetime of the following, and when should they be replaced?

I know this will sound like heresy to someone who is maintaining a car "by the book", but I have adopted a maintenance practice that has dramatically reduced the cost of keeping my cars running.

In essence, it is this: Drive it 'til it breaks, and then fix only what's broken.

Don't go looking for trouble. If the lambda sensor is still working, then why replace it before it stops working?

Obviously this is not a completely black and white philosophy. If your ball joints are loose, you don't wait until a wheel falls off. If your injectors are worn to the point of too rich a mixture, replace them. Consider partial failure to the point of danger or improper running to fall into the "'til it breaks" category.

However, don't get sucked into the "...as long as I have it apart I might just as well fix..." idea. Last night I'm pretty sure I blew a head gasket on my faithful old 1969 Toyota Land cruiser -- my snowplow truck. The cooling system pressurized to the point of first filling, then melting the overflow bottle, which in this case was just an old anti-freeze jug. ('69 Land Cruisers were before the days of sensible environmental practices, and the original system consisted of an overflow hose that just vented to the ground) I blew through three gallons of antifreeze in an hour and a half. So, I'll replace the head gasket, and will lay a straight-edge along the sealing surface and if necessary I will have it machined to keep from immediately blowing another gasket. But I will not do a valve job just because the head is off and it is easy to do. I will not take a ridge reamer to the cylinder bores. I will not use this as an excuse to pull the oil pan and put new main and rod bearings in it or pull the pistons out and replace the rings. Yes, all of that stuff is worn (c'mon, I've been plowing snow with that truck for more than 35 years, after all) but that stuff is still functioning. Yes, it would run better with new rings and bearings and valves in it -- but it runs well enough now to satisfy me.

When I applied this maintenance philosophy to my bicycles, I cut my operating expenses by just about an order of magnitude. And if you scoff at the idea of maintenance "expense" on a bicycle, you have never owned a full front and rear suspension bike with 27 gears, hydraulic disc brakes, and indexed shifters!

tanstaafl.

I think Rob S is more concerned with stocking up on parts that may be harder to get once the manufacturer no longer needs to make them. He's not necessarily looking to replace the items in question right now. For things like a cat, I think there isn't a problem because there should be a billion aftermarket units that can be welded-in. Other parts on the list may be more specific to his model/year.

I know for my SVX I have a stock of fuel filters (because only the OEM fits perfectly), radiator caps, key blanks, door sill panels (made with clips that like to break), grilles, and I plan on adding a MAF sensor to the list since that's already fetching over $300 from dealers.

It's similar to the cache of empeg VFDs, remotes, harnesses, tuners, and metalwork I've amassed.

Nifty instructions, Rob. Thanks for linking them. I'll give that a shot.

I believe that most manufacturers had 10 years as the lifespan for an airbag but most have extended that by another 10 years, presumably after seeing that they are servicable and nothing has degraded in that period.

I would second the suggestion of replacing the cat, especially if the vehicle is experiencing any overfuelling or performance issues. I suspect a main dealer would rob you blind for an OEM unit, so check with an exhaust shop to see how much a quality aftermarket unit will cost.

Gareth

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when should they be replaced?

You know my philosophy on this. When they fall off and you can no longer weld them back together

Lambda sensors are supposed to be replaced every three to four years, normally last for at least ten unless you manage to contaminate them, and may last pretty much forever under ideal circumstances.

Given that the whole point of a catalyst is that it doesn't take part in a chemical reaction, but merely catalyses it (the name is a bit of a giveaway), in theory they should last indefinitely. What breaks is of course the ceramic matrix the rare-earth materials are supported by, and this is dependent on things like mechanical shock, thermal cycling, rich running (the thing gets incredibly hot to the point where the ceramic can actually melt!) and fuel contamination which can chemically kill it instantly. I believe the rated lifetime is normally about 5-6 years, but again normally they're good for about twice that.

Airbags are supposedly rated for I think 10 years. However, there was a recent (Top Gear?) program on TV where they tested a 15 year old Rover 600 airbag by driving it into a large solid obstruction at 30 MPH, and it functioned perfectly. Considering that they really DID drive it, by applying a stuntman to the controls, it's a good thing it did I believe that many of the airbag manufacturers are saying the things are probably good for 20-25 years if they haven't been fiddled with. Eventually the cloth the bag is made of will weaken, I suppose, and the explosive charge will simply pop it in your face rather than hit you with it. The charge itself will last more or less forever.

Seatbelts are supposed to be good for the life of the vehicle. Whatever that turns out to be. The manufacturers would like it to be as short as they can get away with, of course

The injector is probably past it's sell by date.

pca

Recent hearsay from a coworker has it that for some vehicles, running them out of gas a couple of times can generate conditions where, the face of the ceramics glaze over blocking the passages thru.

My '93 Honda del Sol hasn't given me the light yet and my 2000 Honda CR-V hasn't given me any issues. If the light came on I think I'd be afraid to drive the vehicle.