What are typical component lifespans in miles?

[Syonyk]

There was a thread on RX7club a while back discussing the typical lifespan of components in miles, and one guy's replacement schedule - he makes a living doing aircraft maintenance/inspections, and maintains his car the same way. Things get replaced at X miles, regardless of condition. Interestingly enough, he commutes ~100mi/day with his 2nd gen RX-7 (not generally considered the most reliable car on the planet), and it has yet to leave him stranded anywhere.

 

I know most people are are flat broke, and fix stuff when it breaks, but I thought I'd toss out a thread to discuss this sort of thing.

 

I'd like to get an idea of the safe mileages for assorted things. The manual has a lot of these, but not everything. The idea is for a point to replace things where they're not getting replaced when they've still got a lot of life left in them, but also to replace them before their typical failure points. Also, integer multiples of distance on things that are done at the same time would be useful (so you're not replacing timing belts, then swapping a water pump 10k miles later).

 

Thoughts I had:

 

Timing belts: 60k miles, as per factory

Water pump/oil pump: 120k miles (I've had several water pumps fail around 140k)

Coolant hoses: 120k miles

V-belts: 60k miles

Clean fuel injector professionally: 120k miles

Alternator: 120k miles

O2 sensor: 60k miles

 

My change intervals on the ignition system bits are probably WAY short, but... ignition system work is easy, and cheaper than gas right now.

 

Spark plugs: 30k miles

Spark plug wires: 60k miles

Cap & rotor: 30k miles

 

Some items I don't have experience with the failure points of:

 

Fuel pump: ???

Radiator: ??? - generally these seem to fail from age, not mileage.

Axles: ??? (the front are definitely shorter lived than the rear)

Ignition coil: ???

 

Other thoughts? The idea is that a car maintained with this schedule will never suffer a component failure (short of just bad luck or bad parts) that could be prevented by changing something earlier.

 

-=Russ=-

[Subaru_dude]

wheel bearings would probably last a couple hundred thousand right? past that they either need to be regreased, or better yet just replaced. I'd say a fuel pump would last about as long as well. my dad had an ea82 gl with 300,000 on it, and he bought it with 55,000 and the fuel pump still worked fine as far as we could tell.

[Manarius]

Some of the things you mentioned are not mechanical. The ignition coil for example is purely electronic - so what exactly is going to cause it to break?

 

The radiator - there aren't any moving parts, how's it going to break? If you keep your fluid changed, what's going to make it go bad?

 

As for things like timing belts and water pumps - I've got a 150k mile water pump on my car that works just fine. The timing belt is almost 100k old and it still runs like brand new.

 

Wheel bearings depend on use and so do axles. You can't just assign them a mileage that they're going to crap out.

 

I've also got an alternator with 150k+ miles that puts out just as much electricity as it did when it was new.

 

It's different for everybody, but a lot of the parts you mentioned have a lot longer a lifetime than what you wrote.

[Syonyk]

Ignition coils, despite being purely electronic devices, can and do fail. I don't know if old Subies eat coils, but other vehicles can and do go through coils at a fairly regular clip.

 

My mileage is based on when stuff failed on me. I'm sure there are parts that can go longer, but if we can get a general idea of when stuff fails, it would be useful.

 

I've had two water pumps start leaking right around 145k miles. I had a factory alternator quit around 135k miles. So I'd be inclined to say that a water pump, in general, can't be expected to last 150k miles.

 

-=Russ=-

[GeneralDisorder]

Arbitrary - depends on maintenance, condition, usage patterns, evironment (dusty, dry, wet, hot, cold, etc), quality of rebuilt components, brands, etc, etc.

 

There's no point in sticking a mileage value to the stuff - hours of operation is a better metric, but not by much due to the variables I previously mentioned. But - no hourmeter on a soob anyway.

 

It's like asking about clutch wear - one person gets 200k out of a clutch, the next guy gets 25k... it's how it's driven, and the conditions of it's use and maintenance that matter.

 

GD

[nipper]

Some of the things you mentioned are not mechanical. The ignition coil for example is purely electronic - so what exactly is going to cause it to break?

 

The radiator - there aren't any moving parts, how's it going to break? If you keep your fluid changed, what's going to make it go bad?

 

As for things like timing belts and water pumps - I've got a 150k mile water pump on my car that works just fine. The timing belt is almost 100k old and it still runs like brand new.

 

Wheel bearings depend on use and so do axles. You can't just assign them a mileage that they're going to crap out.

 

I've also got an alternator with 150k+ miles that puts out just as much electricity as it did when it was new.

 

It's different for everybody, but a lot of the parts you mentioned have a lot longer a lifetime than what you wrote.

Radiator is exposed to the elements. They clog from not using deminerilazed water. The cooling fins fall apart from the elements (corrosion). A radiator my guess from past exp would be 160,000 miles or 160 months.

 

On a non interference engine you can wait till the timing belt breaks, but i think now all subaru belts last till 100,000 miles (sort of silly making some last only 60, then others 100). Materials have gotten better since then.

 

Waterpump should be changed at either 100 or 120K miles depnding when you do the belts.

 

Wheel bearings are tough, but again probably over 160,000 miles.

 

Altenators no rhyme or reason.

 

Spark plugs have a much longer life, along with wires then subaru says. Usually 100k or more.

 

The ignitor isnt on there. Thats maybe in the 160,000 plus range.

 

Another questionably short subaru interval is brake fluid, which should be changed at whenever brakes are done over 100,000.

 

Cap and rotor depends upon the brand. i had a blue streak last the life of the car.

 

Axles depends upon when the boot rips.

Coil can go for ever

Fuel pump if you dont run the car to fumes will last the life of the car.

 

 

On my two 1980's subarus i never had to change struts, fuel pump, master cylinder. One i never changed the clutch, but did have to change the cables.

I did have to change the universal joint in the drive shaft and shift linkage bushings. Most things you replace once every 150-180,000 miles.

 

 

nipper

[daeron]

mine had (factory?) timing belts go at 106, the alternator went at about 115, the water pump at 130. rear wheel bearings went out after i overtightened them after doing rear brakes (first time??) at 120K. just had the starter finish quitting.. it died at about 125K but i remanuHactured it into lasting me until 139958 miles.. so close to the 140K mark, alas. also just did tierod ends. radiator at about 135K. factory struts, front wheel bearings, fuel pump, steering pump, CV axles, ac compressor (i think) i know i redid front brakes but at 140K thats been done a coupla times im SURE.... each headlight bulb went out within 500 miles of each other (kinda cute, like an elderly couple...) around 125 i think....

 

My judgment: about 125K its a good idea to read the HTKYSA and do all that. theyve pretty well gots it sorted out there.. and some of the limits they set are a bit conservative just because parts a bit better in some ways (gaskets come to mind, and timing belts and seals...)

 

now watch. my AC compressor, fuel pump, all four struts, the drive axles, front wheel bearings, and the steering pump will all die within a month on me.

 

anyone know a good method of warding away gremlins once youve invited them in??? my lousiville slugger seems to be missing...

[nipper]

 

anyone know a good method of warding away gremlins once youve invited them in??? my lousiville slugger seems to be missing...

 

heheh i know we probabaly all just jinxed ourselves ..... well at least we know who to blame

 

nipper

[pyromanic]

What does that mean "wheel bearings went out after i overtightened them"? The pre-load on Soob wheel bearings is engineered into the system right? You can't overtighten them. I did all four of mine right after I bought the car, and was kind of freaked out when discovered that. Or am I wrong? (it happens!!)

 

Pyro

 

mine had (factory?) timing belts go at 106, the alternator went at about 115, the water pump at 130. rear wheel bearings went out after i overtightened them after doing rear brakes (first time??) at 120K. just had the starter finish quitting.. it died at about 125K but i remanuHactured it into lasting me until 139958 miles.. so close to the 140K mark, alas. also just did tierod ends. radiator at about 135K. factory struts, front wheel bearings, fuel pump, steering pump, CV axles, ac compressor (i think) i know i redid front brakes but at 140K thats been done a coupla times im SURE.... each headlight bulb went out within 500 miles of each other (kinda cute, like an elderly couple...) around 125 i think....

 

My judgment: about 125K its a good idea to read the HTKYSA and do all that. theyve pretty well gots it sorted out there.. and some of the limits they set are a bit conservative just because parts a bit better in some ways (gaskets come to mind, and timing belts and seals...)

 

now watch. my AC compressor, fuel pump, all four struts, the drive axles, front wheel bearings, and the steering pump will all die within a month on me.

 

anyone know a good method of warding away gremlins once youve invited them in??? my lousiville slugger seems to be missing...

[daeron]

oops, meant to be clearer on that. sometimes for the sake of brevity i skip things i shouldnt. sorry.

 

well, you have to take the stub axle nut off to get the drums off, right? when i went to re tighten after the brake job (which was the BESTEST drum brake job ive ever done) i read my haynes book.. and the haynes book lists two different torque specs for the rear wheel bearings.. it lists a high number like 130 in the specs breakdown, next to the front spec.. but then in the procedure it tells you 35 ft-lbs... but i tightened the wheel nuts up HARD and the bearings gave out

[GeneralDisorder]

2WD rear wheel bearings are completely different than 4WD. You guys are talking apples and oranges and aren't even aware of it

 

..... yeah. You *can* overtighten the 2WD ones a lot easier than the 4WD version. But it's possible on both. Just really, really stinkin hard on the 4WD's. 140lbs is the axle nut spec on the 4WD (not sure about the 2WD, but the bearing is a lot smaller...).

 

GD

[pyromanic]

2WD rear wheel bearings are completely different than 4WD. You guys are talking apples and oranges and aren't even aware of it

 

..... yeah. You *can* overtighten the 2WD ones a lot easier than the 4WD version. But it's possible on both. Just really, really stinkin hard on the 4WD's. 140lbs is the axle nut spec on the 4WD (not sure about the 2WD, but the bearing is a lot smaller...).

 

GD

 

And I forgot about that wierd nut behind the backing plate on the rears on 4x4s anyway, which I think is what pre-loads the bearings. But yea, I don't know squat about the two wheel drives, so apples to oranges. My bad.

 

Pyro

[daeron]

well, i figured that was probably the case.. but i DO have my vehicle spec listed up there on my info blurb... and that is probably the first post ive ever made where i assumed anyone knew anything about what "my" car was..... go figure:rolleyes:

[DaveT]

 

Timing belts: 60k miles, as per factory

Water pump/oil pump: 120k miles (I've had several water pumps fail around 140k)

Coolant hoses: 120k miles

V-belts: 60k miles

Clean fuel injector professionally: 120k miles

Alternator: 120k miles

O2 sensor: 60k miles

 

 

Fuel pump: ???

Radiator: ??? - generally these seem to fail from age, not mileage.

Axles: ??? (the front are definitely shorter lived than the rear)

Ignition coil: ???

 

-=Russ=-

 

Coolant hoses 5 years. Age & heat kills them. All of them, not just rad & heater.

 

Water pumps usually bad abouth the time my timing belt break a little over 50K. I can't say I never had a timing belt make it past 60K, but it is rare in my >16 years experience with EA82s. I try to change them around 40K.

 

Alternators - usually 1 of the brushes and the bearings replaced in the low 100Ks.

 

O2 is tough. The can fail in a way that does not trigger the computer to light the CEL, but still be off enough to fry the cat. Best way to avoid that is replace every couple years or so. Mostly I have changed them when the CEL came on, only 1 time fried the cats.

 

Around here, (CT) radiators fail due to road salt eating away the fins. Then the pressure cycles stress the flat tubes - they don't stay flat without the support of the fins - until they split. The "duct" around the electric fan is fantastic at collecting crud that rots the fins away quickly.

 

I recently had a fuel pump go intermittant. My spares had the damper rotted to the point of leaking, so check that your pump is rustproofed.

 

Replace the OEM EGR & purge vacuume solenoids with Toyota ones.

 

Check the Diff oil in the automatic trans, if you have an auto.

 

The oil leaks that develop over the years / miles help preserve the underside of the car, but adding oil all the time gets annoying.

 

Battery 5 years. Time & deep discharges kill them. I have had them go longer, but after 5 years the battery is not what it was when new, even if it still starts the car. I put the biggest battery that physically fits in the tray area. Handy for jump starting w/my 1AWG jumper cables.

[bgd73]

this would be impossible to nail down exactly...

what if to say.. signs that parts are going, and document it yourself?

I too worked with aircraft, inspections. The big thing is inspections, no set intervals for repairs, unless deemed to be that way, even if unnecessary. But we aren't running airplanes heh?. Cars are unpredictable. The only interval I agree with on the soob ea82 is the timing belts.

I have had too many overlasting or underlasting parts to even think of intervals.

fuel pumps for 17 years- and failing in another younger,

timing belts vary- lean conditions, bad oil habits change that dramatically.

water pumps where I live squeeze out a few drops in mid winter frigid... it does not mean bad. That tolerance is almost welcome, come warm weather.

I even have noisy tensioners and pulleys- exactly conformed, still lubed, for my crazy environment- another person may change them.

Rear bearings on 2wd will make noise at lower miles than expected- go with anything but oem when it does it... whatever the miles/years are.

Since we aren't running aircraft, taking the full realm of its disciplined maintenance is absurd. Go with the flow man, chill out.

Everything on its way to failure gives a sign... everything. Even if you can't find the domino effect that led to a particular parts demise, for seemingly no reason, at first glance. For me personally, even the only timing belt I broke, under the 60k interval, was when the fuel pump broke at the same time. Lean condition, before no fuel at all, snapped it off from heat of slowly dying pump affecting the heads.. See what I mean? it is a "go with the flow" kinda car.Unless you have the Federal Aviation Administration grounding all subes because one broke a rotor and crashed- I would really relax...

[Syonyk]

I agree, but I just hate sitting on the side of a road going, "Well... crap. Should have taken care of that a while ago."

 

Also, I disagree that all components will give warning before failing. Some stuff just fails in a hurry (alternators come to mind). Also, replacing stuff early means you have a known good spare that will at least get you home if needed.

 

-=Russ=-

[nipper]

Look at it this way, you can replace a part on your schedule, or on the cars schedule. The cars schedule usually reqyuires a tow truck in the middle of a cold rainy night. i prefer my scheduale, its much more convient.

i also disagree with the go with the flow theory. It goes against everything i know as an engineer. You can cause just a lot of damage with a ball joint or a tie rod failing at speed. Telephone poles tend not to jump out of the way.

Parts do give warning that they are going bad, but not everyone can pick up on the subtle nuances, or is trained to. Noises that build up gradually over time can escape an untrained ear. Also noisey bearings would fail an "inspection". i too worked on F15 compnonets and other air plane systems. i would never let my car becomes a bucket of bolts. There is no excuse for a maintanece part failing becuase it wasnt rreplced on scheduale.

Older subarus are more tolerant of this method, but i still don't like getting stranded.

 

nipper

[idosubaru]

if it's about being stranded then replacement isn't necessarily the way to go. the way to go is to decide which items you can store easily that are likely to strand you. fusible links, the ignitor, ignition coil, timing belts, crank pulley and timing pulleys and alternator are nice extras to keep in the lower trunk trays (if you have them).

 

water pumps and thermostats are cheap and absolutely necessary so i replace them with every timing belt. i'd add radiator caps to one of the shorter lists for the same reason.

 

timing belt pulleys should be regreased or replaced at 150,000 - 200,000 (for reliability of course). or carry extras in the trunk if you don't mind doing them on the side of the road.

 

wheel bearings are nice to replace at 150,000 if you travel long distances.....200,000 if not. but again...this is all dependant on how reliable you want the thing to be.

 

i've found that a good charging system with new batter, good alternator, new battery cables/connectors and possibly even a heavy gauge charging wire if you like will keep the alternators running for quite some time...i've had very little alternator troubles even at 200,000 miles.

[bgd73]

I agree, but I just hate sitting on the side of a road going, "Well... crap. Should have taken care of that a while ago."

 

Also, I disagree that all components will give warning before failing. Some stuff just fails in a hurry (alternators come to mind). Also, replacing stuff early means you have a known good spare that will at least get you home if needed.

 

-=Russ=-

That is the point I just made.. even my fuel pump breaking had signs I shrugged off as dirt in the fuel system. It was my own fault. What set interval for the 200 dollar fuel pump is worth it? Luckily my carbed dl was matched cheaply with a 30 dollar 5-7 lb psi monster(it was huge in comparison to original)- that pump would have gone to 20 more years for all I know.

Alternators do have signs- its like lightning burp and gurgles- a keen eye catches it. Mine don't, but guages to monitor are a good thing there. Isn't that why they have them? Cars are as durable as thier environment. Would this in writing have a "Northern Arctic" section and a "Southwest Desert" chapter? (I am speaking of usa of course)

Being stranded sucks, but one can only go so far on thier own intuition and intervals of maintenance before something happens. I also learned that on aircraft.The best manual for intervals is time with the owner of the car. Another note is... what oem parts have to go away from your car forever to change the intervals of repair entirely?

2 points I have learned personally are the crappy plastic side tanked radiators in the Loyales getting scrapped, and on my 2wd, use anything but oem rear bearings.Even the bosch plugs changed many things, not to think of again. I am not sure what could be put into writing and be useful, unless it is specific to one car in its environment, and many years with one owner who would want to documnet it for personal reasons. (I can really see an Aircraft mechanic being inspired by this idea- I was one, and am not).

[Snowman]

I definitely agree that component lifespan is tied to the vehicle's environment. That's why manufacturers publish different maintenance schedules for different environments. You have to look at how YOUR car is getting used and then determine a maintenance schedule from there. Let's use timing belt life as an example. If you live somewhere where the temperature stays between 50 and 80 degrees, there is very little dust or precipitation, and you don't shift at 6 grand very often, your timing belts are likely going to last 100k or more. In that case, you could have a standard service interval of, say, 90k, and never be stranded. If you live in a hot or cold environment (EA82s EAT timing belts in Fairbanks during the winter), or have lots of dust, or drive through deep water and mud, your timing belts may not last past 30 or 40k. In that case, if you want to avoid being stranded, I'd carry a set of belts with you, and shorten the interval accordingly.

 

You also have to consider exactly what would happen if a component fails. Most Subaru engines (mainly the EJ25 and EA82) are prone to major damage from overheating. Therefore, I see it as worth the time and money to replace the coolant hoses and change the coolant every couple of years. That, coupled with keeping an eye out for leaks, means that my engine is likely to never get severely overheated and is therefore probably going to last a lot longer. Of course, your environment also plays a big role in deciding what might happen in the case of a catastrophic failure. If you break down in Seattle, you might have to catch a ride from a friend or get a tow. No biggie. If you break down 60 miles outside of Tok in the middle of the night during the winter, you might not see another car for 8 hours, and at 40 or 50 below, things could get serious pretty quickly.

 

I guess the bottom line is that you should base your maintenance schedule on how your car is used, because that determines both how long parts will last, as well as how serious it is if your car breaks down.

[thealleyboy]

The best case scenerio is if you have good records of past maintenance. Then you can set up a new schedule without replacing a bunch of stuff unnecessarily. I like to look at maintenance more as "level of confidence" rather than a specific interval. If you don't know what's been done in the past, you really have to replace items to get up to a baseline of reliability. For example, my wagon has 112k, and I don't know the history of timing belt replacements. I will be replacing it - regardless of visual condition at 120k.

If you get on, and stick with the suggested maintenace schedule, you'll rarely have any problems in those areas. However, things like brakes/bearings/front end part replacement are really not addressed in the maintenance schedule. I usually do those anytime the opportunity presents itself and the component has some wear. I also usually drop the entire exhaust and rebuild it when any section fails. The timing belt procedure is another good opportunity to deal with any glaring issues, though component replacements make more sense every other belt (120k).

good luck, John