My dear daddy (may he rest in peace) worked in a Packard dealership in the 1930's. At that time, the sales people told customers that they MUST change the oil every 2,000 miles. The mechanics would drain the oil out of the Packards, save it, and use it in their own cars.
A co-worker of mine many years ago was going to night school about 60 miles away, and had been driving back & forth to school for years in his old Toyota Corolla. The odometer only went up to 99,999, but he assured us that he had well over 200k miles on this rusty little beast. I asked him how often he changed his oil and he said, "Every 30,000 miles or so, if I remember to do it." One might mention that with a 1.6L fourbanger, that car was constantly running hot.
I used to live next door to a chemical engineer who worked for Gulf Oil. I asked him how often I needed to change the oil in my car. His surprising answer: Never.
According to him, the "change every 3,000 miles," rule was appropriate until about 1960, when the oil companies started making higher-quality oil. Before that time, oil would lose its viscosity over time, due to the heat of the engine. Since then, however, the oil never loses its viscosity under normal use, and it's the DIRT IN THE OIL that is the concern. In his car, he would change the FILTER every 7,500 miles and add some oil occasionally as necessary, but he never saw any need to CHANGE the oil.
From these stories and personal experience, I gather than the only reason anyone would recommend changing oil more freqently than once every 15k miles is if he is trying to sell oil changes. It is really unnecessary. In the Old Days, it was necessary to change the oil in a new car at a thousand miles or so, because the "fresh" engine might have microscopic metal filings floating around and scarring the pistons and cylinder walls, but with modeern manufacturing techniquest that's no longer the case.
My daily drive is a H.O. Chrysler turbo, and I change the oil & filter every 5,000 miles, JUST SO I CAN TELL THE NEXT OWNER TRUTHFULLY THAT I DID THAT. I actually think it's overkill.
A co-worker of mine many years ago was going to night school about 60 miles away, and had been driving back & forth to school for years in his old Toyota Corolla. The odometer only went up to 99,999, but he assured us that he had well over 200k miles on this rusty little beast. I asked him how often he changed his oil and he said, "Every 30,000 miles or so, if I remember to do it." One might mention that with a 1.6L fourbanger, that car was constantly running hot.
I used to live next door to a chemical engineer who worked for Gulf Oil. I asked him how often I needed to change the oil in my car. His surprising answer: Never.
According to him, the "change every 3,000 miles," rule was appropriate until about 1960, when the oil companies started making higher-quality oil. Before that time, oil would lose its viscosity over time, due to the heat of the engine. Since then, however, the oil never loses its viscosity under normal use, and it's the DIRT IN THE OIL that is the concern. In his car, he would change the FILTER every 7,500 miles and add some oil occasionally as necessary, but he never saw any need to CHANGE the oil.
From these stories and personal experience, I gather than the only reason anyone would recommend changing oil more freqently than once every 15k miles is if he is trying to sell oil changes. It is really unnecessary. In the Old Days, it was necessary to change the oil in a new car at a thousand miles or so, because the "fresh" engine might have microscopic metal filings floating around and scarring the pistons and cylinder walls, but with modeern manufacturing techniquest that's no longer the case.
My daily drive is a H.O. Chrysler turbo, and I change the oil & filter every 5,000 miles, JUST SO I CAN TELL THE NEXT OWNER TRUTHFULLY THAT I DID THAT. I actually think it's overkill.