In reality, that is what it comes down to.
In theory, it is a bit more complicated.
Chris Watson - (I think unitentionally) posted something inaccurate in reply #24:
"Vehicle manufacturers warrant their products to be free of defect in manufacture or workmanship. All claims must be
covered unless a vehicle manufacturer proves a failure is lubricant-related. The manufacturer may not arbitrarily blame
a failure on the consumer’s practice of changing oil at extended intervals."
Magnuson-Moss Warranty Act
https://www.mlmlaw.com/library/guides/ftc/warranties/undermag.htm
Regarding Magnuson-Moss - there are two conditions that affect oil changes:
- Use of aftermarket parts/oil. This is pretty well covered and understood under the tie-in sales provision of the law. Hyundai can't REQUIRE you to use their filters or oil, unless they provide you the filters free of charge. Now, they can say that the aftermarket filter/oil did not meet their quality standards, but they technically have to PROVE the aftermarket part caused the failure. (There's a bit of legal cat and mouse here. On the one hand, if Hyundai says they are convinced the Fram filter you used caused your engine to fail, it's fairly difficult for you as the consumer to prove that the engine failed for causes totally unrelated to the Fram filter and they owe you a new engine. OTOH, typically Hyundai doesn't usually want the publicity of saying they won't pay for an engine b/c you used a $3 filter instead of their $6 one, nor do they typically want Fram's lawyers suing them for loss of revenue from declining sales b/c nobody will buy a Fram filter to use in a Hyundai ever again.) (I'm running a Fram filter right now, so I picked this example.
- Not following the specified maintenance interval. I really don't think MMWA covers this. The Act basically says the warranty has to clearly say what is covered and for how long and what is required to maintain coverage. IANAL, but my interpretation is the manufacturer can require you to change the oil every 500 miles to maintain coverage if they so choose to. They just will lose sales b/c their cars are more expensive to maintain. I do not see any provision in the act that says the manufacturer has to
PROVE that failure to change the oil at the specified interval caused the failure. Tie-in sales are really a stretch here - as the oil change doesn't have to be done at the dealer, so your only argument is that the corporation set a low 7500 mile OCI when 15K would have worked b/c maybe 50-60% of owners will come back to the dealer even though they don't have to, so it generates more money for the dealer. And as above - even if they DID have to prove that the longer OCI caused the failure - if they claim you should have changed it at 7,500K miles and they aren't covering it b/c you didn't, it is hard to prove that the longer OCI did NOT contribute to the failure, and (from my interpretation of the MMWA), you would likely lose this case.
All that said and done -
Hyundai's OCI is 7500 miles and the PT warranty is 10-years or 100K miles for the original owner. If I assume a $50 oil change (I can diy, or do dino for around $20), I will spend $666 (the devil number) in oil changes over the warranty period. (If I drive less than 10K miles a year, I will spend less b/c the warranty will expire on calendar time).
For the turbos - let's assume a 5K oci (I think it is specified something like 3750 for the first oil change and then every 5K after that in the OM), so $1000 for oil changes.
Toyota has a 10K OCI, so only $500 for the 100K interval, but their PT warranty is only 5-years or 60K, so only $300 for the warranty period.
If we use your AMSOIL 15K interval with Hyundai non-turbo - the cost is $333. So we are talking about a savings of $333 over 100K miles or roughly $30 per year to risk voiding any warranty on the engine.
Again - I am not telling you that you CAN'T run a 15K OCI, the oil and the engine will likely handle it. I just want you to know that if you choose to do so and have an engine failure, Hyundai (from what I can tell, properly and legally) will most likely NOT cover it under warranty.