Theoretical "best" annual miles for engine life?

[Ed_Flecko]

I know it's going to vary from engine design/type to engine design/type, driving style(s), etc., but what I'm wondering is if there's a general rule of thumb as to how many miles are too few versus too many?

In other words, it's always interesting to find some classic car that's been driven by Grandma to the grocery store and home and has ultra low miles, but is that type of driving really good for the longevity of the engine? It sounds like most people agree that a motor is "extreme service" in that the oil never reaches normal operating temperature which can cause sludge build-ups, etc., etc.

At the other extreme is the fact that motors do wear out (although I had a friend selling her Honda to my co-worker who asked how many miles it had on it, to which she replied, "Oh that doesn't matter...it's a Honda"), so too many miles is a bad thing too.

Where's the balance? What's low mileage, but not too low, or is there such a thing? Maybe a "sweet-spot" would be 20-30 minutes of highway miles and that's the bulk of your driving?

Ed

 

[Quattro Pete]

Originally Posted By: Ed_Flecko
but what I'm wondering is if there's a general rule of thumb as to how many miles are too few versus too many?

I don't think there is such a rule of thumb. What would be more important to me is how those miles were accumulated - short trips vs. longer trips.

 

[Pontual]

I'd say: Run a least once a week, for one hour plus, better 3 times a week, to avoid corrosion on cylinder walls and diplaced iron eating your bearings, specially if usind a thin oil. Use a drainplug magnet if it is used less than once a week to retain those rust particles. Mileage doesn't matter much because is dependent on the gear used. Highway mileages is better for the engine longevity, since it makes the oil getting to optimum operational temperature (about 185-200F).

 

[Ed_Flecko]

Originally Posted By: Quattro Pete
Originally Posted By: Ed_Flecko
but what I'm wondering is if there's a general rule of thumb as to how many miles are too few versus too many?

I don't think there is such a rule of thumb. What would be more important to me is how those miles were accumulated - short trips vs. longer trips.


I wondered if that was the case.

I personally have never "found" a classic car with uber low miles, but I wonder if, in many instances, you have a lot of motor problems just because the motor was driven TOO little?

Ed

 

[Silverado12]

The easiest miles I ever put on a vehicle is when I would drive 30 miles to my trucking job, then about 5 days later drive the 30 miles home. Pretty much all but the last 5 miles highway. Ended up with super low miles on the car before I gave it to my son.

 

[MolaKule]

There is no such thing.

 

[JHZR2]

No such thing. Time at temperature is what degrades engines, but the key is extreme temperature, which also equates to excess load.

So long story short is that its best to get it up to temperature, drive with reasonable load so that there are no excessive temperature or pressure excursions, and yet there is reasonable load so that things stay clean and clear.

 

[ecotourist]

Seems to me that the best strategy to get the most miles out of an engine would be driving as many many miles as possible in the least time possible. The rest of the car will eventually wear out, and that would determine the maximum miles for the engine (unless you move the engine to another car for more of the same). In other words (with reasonable maintenance) the engine will outlive the rest of the car.

I seem to recall in the mid 1980s Mercedes Benz driving their small sedan for hundreds of thousands of miles at high speed with only stops to change drivers, gas up and periodically change oil and tires - just to show it could be done. A lot of miles in no time at all - more than most people would ever put on in the normal life of a car.

 

[Trav]

Don't run it at all, it will last until it rots away. I don't think there is any such rule of thumb or otherwise.
Run them once in a while and get them warmed up and it will be fine.

Some properly prepped museum car don't run for decades and are fine when they do.
The fewer starts it has and the longer it is run at operating at temp the longer it will live.

 

[supton]

What is the engine life? Time until the crosshatches are worn off, or the rings are shot, or until the owner is bored with the car?

 

[CBR.worm]

I would say until it fails - I expect mine to fail spectacularly at some point.

 

[silvercivicsi]

My uncle commutes from San Diego to Los Angeles 5-6 days a week. His last two Tacomas have gone 600,000+ before either being totaled or traded in. Original motor and transmission on both.

So with 90% highway miles and good service schedule I think you would G2G for close to a million miles.

 

[Kestas]

One metric for engine life is when it burns a quart or more of oil every 500 miles.