I’m late to the dance on this link, but always have my 2 cents....
From a different perspective, we ran between 250-300 Rangers and S10s. This was mid 90s to 2009 when I sold my shareS. They usually lasted us 3-4 years (we sampled on construction sites and my guys were brutal on them). We did about 35,000-40,000 miles a year. We bought or leased 25-30 trucks at a time and took delivery of 4-5 per month. +/-
We had 3 maintenance shops in the southeast, and we changed our own oil. We targeted 3,500 miles, and rarely ever went over 4,000.
We bought the absolute cheapest oil we could get that met the truck spec. We bought the absolute cheapest filters we could that met the truck spec. We had 3-4 engines fail a year, whether new or 90k. We always had to fight a little for the warranty, but we always got much more than the repair costs/replacement.
We tracked maintenance, which oil, which shop, everything, and never found any significant correlations except don’t buy dodge for heavy duty use. although we did international work, my partners and I would only by US-made trucks.
what we learned. If you track your oil changes, it’s pretty easy to get warranty coverage if you know how to track it: you need 3 bits of information. Date, mileage, and if it’s not specific in the printed receipt, you need the name/part number of the oil and the Ford/chevy spec. You have to verify the date, mileage and spec, not the price. Hand written notes are fine, but I’d use photos today
the other thing we discovered was training records. Doesn’t have to be much. We got a maintenance manual for the truck, the kind shops use. Haynes or chitons are fine. Then we copied the section on oil change procedure onto a “training” form, went through it with the mechanics, and they and we signed the form that they had been trained in proper procedures, and filed it with the truck records. You can make a similar form for yourself at home even if you copy the procedure off the net or from a buddy.
now, I’m not going to blow sunshine up your collective butts and say it didn’t hurt that we bought so many trucks, but I am not aware we ever played that card. The warranty claims were with Ford/Chevy, and not the dealership the way we bought them, fleet sales.
you get the idea, always my 2 cents!