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Do engine parts have basic life expectancy?

When it come to say water pumps, or starters or altanators and such, do these part have an age/milage that they should be replaced at no matter how they operate or do you just wait till the break?

I’ve replaced perfectly good water pumps along with timing belts as a preventive measure, but I’ve never replaced a functioning starter or alternator unless it was giving indications of impending failure.

If it ain’t broke, don’t fix it.

You just let them break. Their life expectancy is affected by so many things there’s no even approximate estimate you can make for their life. Major exceptions are replacing something you’re taking off anyway as part of another item’s replacement or maintenance, or replacing something that’s much more accessible because of that (like a water pump when you replace a timing belt).

If you happen to be working in the area and have removed stuff that would be in the way of replacing the other parts, you may want to do both. The decision depends on what is being replaced, its condition, cost of parts, time involved etc.

There is a design life for most parts. Since every car is subjected to different conditions the design life isn’t very useful in the real world.

A person can kill a starter very easily if the starter is cranked too long and overheats. For instance a car in poor tune that starts only with a lot of cranking could need a new starter every couple of years while the design life is ten years.

I agree on the water pump. The vast majority of the cost of replacing the timing belt or the water pump is the labor required to get down to the part. Once you’re there, you may as well replace them both, otherwise if it does fail, you will be paying for the labor all over again. This is true for a handful of other parts as well, but in most cases it’s fine to wait until they’re about to break to fix them.

Well i am in a situation where I am going to have to have my timing belt replaced on my Kia sedona. I have been told that since I am having that done to just go ahead and replace the water pump while they are doing that. However, the dealership, whom I am having do this stated this was not needed as they have not seen any issue with water pump failures on this van till around the 200,000 mile mark and I am another change away before I reach that.

I will accept some current real world gained input and review the blanket policy (first time I heard it was early 80’s)of always replacing the water pump at every timimg belt change.

I am more suprised that a Dealer turns down work.

I was to, i was also SHOCKED that they came in price wise cheaper then all the other places I checked to do the work. PLUS they will give a rental for the day at no cost. They will change out the water pump for additional parts cost but really don’t feel it’s neccessary.

Do you know this dealership? I mean to say, are you in a relationship that is established?

They seem to be one of the good dealers, honest and trustworthy. A lot of mechanics would have just done it and made a few more dollars, these guys seem to have you and your long term satisfaction in mind.

You may be able to verify their claim independently on a Kia-oriented forum somewhere.

The only component I see as being worth while to change are any components that contain sealed bearing units, that see a hostile environment.

Some examples:

Water pumps contain these bearings. The impeller shaft runs through one, and seals the coolant in, while allowing the pulley to spin the shaft.

Idler and tensioner pulleys (serpentine belts, and cam belt system) contain these bearings. I would replace these bearings somewhere between 100k to 150k miles, or shortly after a failure of the coolant system that gets the pulleys covered in coolant.

Famous on Porsches are the Intermediate Shaft (IMS) bearings.
Same type of bearing you see on pulleys, and tensioners.
When this bearing fails, the valves crash into the pistons while the engine is running.
This then leads to full engine replacement, to the tune of $13k to $35k dollars, depending on which model of engine it was.


This is a good and fair question but there is no definitive answer. There is no doubt that vehicle mfrs have minimum life test standards for these items under what is estimated to be simulated extreme customer usage. These test standards may differ among various mfrs and your particular situation may be more or less stringent than the test standard. For example, one person might consider a good battery to be cheap insurance and will not stress his alternator as much as someone who keeps a battery until it is dead for sure and then keeps going with an occasional jump. Another might drive more at night with headlights on. Seasonal variations from north to south can affect alternator and starter life to an unknown extent. Fan belts have automatic tensioners now but one tensioner spring might stress a water pump bearing more than the next with a slightly weaker spring.

Lab conditions can never simulate reality so a mfr can only try to do what is needed for customer satisfaction. Design life can be adjusted upward as indicated.

Meanwhile, you can carry some spares to help minimize down time. I did just that with a rare car with a lot of miles that we took on a long vacation. I brought a water pump and a voltage regulator. I had a spare driveshaft but left that at home.

No, they are just the Kia dealership on my side of town. i thought I would just stop by and ask them the costs for fun figuring as a dealership they would be WAY more expensive. He gave me the price and even told me about a on line coupon for a $40 savings which would reduce the price even more and that they also provide at no cost a rental car. Their timing belt change also includes a new serpentine belt, but not the water pump. When I asked him why not the water pump that is when he said that he has not seen any go out and last way past 200,000 miles on this van. he said they can do it since it is right there and i would have to add on the cost of the water pump to this price he quoted me.

Water pumps I’d replace with at timing belt. I’d say they’re good for about 100K. Starters/alternators? Replace when they die or are showing signs that they’re about to.

They’ve definitely gotten better—used to be that you’d have to replace a starter and/or alternator every few years. The last alternator I had to replace lasted 210K, and the car is still on its original starter.