Main differences between "regular", "high mileage", and "Truck/SUV" oils?

What are the main differences between high mileage oils and ones not specified for that purpose? I see the high mileage costs a tad more for the most part.

Also, shortages have caused this to be the only one available in a lot of places around me. Is there any negative to using this in an engine that is tight with good compression and doesn’t leak or burn oil besides the fact it might cost a tad more?

Also, I see oils specified for Truck and SUV use but they are the same exact weight as the regular specified oil. So, you can get regular, high mileage, and truck/SUV in 5W20. How much of this is just marketing?

High milage oil have additives to swell seals, reducing leaks, as far as I know. Nothing you need, I don’t know (but doubt) if it would do any harm.

As for ‘Truck and SUV’ labeled oils, beats me, sound like just marketing.

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The only issue I could see is if you went from high mileage back to regular. This is how it was with synthetic back in the old days but that seems to no longer be a problem.

I see that many brands now have multiple versions of synthetic like Pennzoil synthetic, Pennzoil Platinum, and Pennzoil Ultra Platinum. The same goes for Mobil 1. You have regular, advanced fuel economy, extended protection, annual protection, high mileage, truck/SUV, etc. I figure for 5000 mile changes like I do that there is no reason to buy any that have claims of 20,000 mile or 40,000 mile life if I have to pay extra. I have always read and been told good things about the extended protection (gold label) and the price is usually about the same as regular so that is what I have tried to stick with. It has never caused me any problems and engines with 80K on them have no discoloration on the top part of the head you can see from within the valve cover when you have the oil fill cap off. It is just shiny aluminum like it was from the factory.

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Aside from Syn or Dino oil it comes down to additives.

For example, the difference between Techron Syn which is used for HD Diesels and Techron Syn Classic Car are the zinc replacement additives which are great in old flat tappet engines but are a potential problem in modern diesels.

I have modern cars with 200,000 miles/20 years running fine on regular Syn and 70 year old cars, original engines, running fine on Dino. It’s simply a matter of using the manufacture’s recommended oil changing at recommended intervals and more important. doing regular maintenance.
Amazing how much better a car drives after it’s washed, waxed, interior cleaned and vacummed. :rofl:

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Local garage has blk Friday special.
8 oil changes reg oil $100
8 oil changes hi-mile 200
8 oil changes syn oil 300
So, there’s a big diff obviously.
Filter disposal, shop fees, taxes extra. Hehe

I doubt there’s much actual performance difference. The oil’s APA rating (eg SN etc) and the viscosity rating (eg 5W-20) are the most important oil-performance parameters imo. Some manufactures spec synthetic-only of course. There used to be a separate APA rating, “C”, for motor oils designed for diesel engines, eg CC. I don’t think that is used these days.

I figured using a “high mileage” oil wouldn’t harm a newer engine. It isn’t like this is a snake oil additive or anything. As for high mileage and truck/SUV oil, I wonder if they are at the higher viscosity limit of the allowed range for their weight.

Yes, I always heard S is for spark ignition engines and C is for compression ignition engines. It looks like the C rating is alive and well on this modern specs sheet. There are no S ratings listed although I do run this oil in outdoor power equipment without any emissions control equipment. The additives in this would likely foul catalytic converters and oxygen sensors.

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Here is one with CF specs as well as several S standards, plus many others. Mobil 1™ FS 0W-40