Long Life Dakota Story
 

Here is the link to the story of the 623,000 mile Dakota.
https://www.allpar.com/cars/stories/shatto.php

Great story.

I remember my father telling me that an engine which is used day in and day out like yours can go many hundreds of thousands of miles before wearing out. According to him, the culprit in most early demise of engines was due to acid build up in the oil, which happens when the car is used for short trips, e.g. the little old lady who only drove the car to church on Sunday. This is why he was skeptical of frequent oil changes on cars which got a lot of use, and why he laughed when commercials came on which touted some premium oil, using for its example of how well it worked, some police department's or taxi service's experience.

So it could be that your truck's very impressive mileage record may have came as much from your style of driving (the acid never got a chance to form), and good maintenance as much, or more, than from using Amsoil.

Edit:

For the record, I change my oil far more frequently than he did, I was sold after seeing a friend's Honda CVCC engine (which got religious 3k mile oil changes) torn down at 120k miles...inside still looked like new. I had not long before rebuilt a car with just a few more miles that had bucketfulls of sludge, and the top rings had a 1/8" gap. The only reason the Civic was torn down was due to a misprint in the service manual...the number of quarts of transmission oil was listed as the number of pints...he eventually wore out the transmission. When he and a friend were rebuilding the transmission, since the engine had to come out anyway, they decided to rebuild it, figuring that since it was a little cheapie Japanese car, it had to be just about worn out.

In my observation, some experience, and personal opinion: Almost any vehicle driven hundreds of miles per day, maintained decently, and driven nicely will last a staggering amount of miles. When you're willing to include rebuilding the engine (for cracked cylinder heads and burnt valves), that staggering number gets even more huge.

Still, 623,000 is a damn fine accomplishment. I'd say Ford Man's 500,000 mile Escort is a bit more impressive to me since it's way older and not driven as many daily miles, and that lady with the million mile Camaro is downright amazing....but the 623,000 mile Dakota is still huge!

Damn Magnums and their cracked cylinder heads!

Since yours went to 350k I feel better about mine... lol

My dad felt the same way about high mileage cars. He said that the car that didn't get driven much was going to be a problem vehicle. Before my dad retired he used to drive 70,000 - 90,000 miles/year for work. His company would buy him a new car every year, and in many cases he would buy the "old" car when the company bought him a new one. He figured it was a 1 year old car, nobody had driven it but him, and he usually bought them for about $3,000. He could buy a car from the company, drive it for a year or 2, and still sell it for more money than he paid for it.

-Jay

Very impressive.

I'm curious about the cracked cylinder heads at 350K miles.

I have always assumed that heads only crack when the engine is overheated- did the engine overheat immediately before the heads cracked?

It's common. The iron heads on Magnums crack all the time. Most of them have cracks in the heads and run fine for many, many years. In fact, his engine probably ran 300k on those heads with cracks in them and my 5.9 at 52k probably already has one or two.

Finding heads that don't have cracks is pretty hard to do in that series of engines and a worthless venture since they'll end up cracked later on anyways.

The Magnum engine heads have 'heat treated' valve seats. The area is 'tempered' as it were, and this works pretty well for the design life, which I would guess is at, or less than, 350,000 miles.
The machinist said that there was two problems; cracks too bad to fix and valve seats too worn to re-cut.
He also said he had seen Cummins rebuilt heads that came from the factory with cracks.
The only time I had an overheat problem was when the A/C died. Kidding. The readiator was half-plugged with stop leak.