changing your own oil will not void the warranty.... not at all, here are some things that will not void your warranty, but will put the liability on someone else other then the dealer.
If you go to a jiffy lube, and they change your oil and leave the drain plug out of the car or do ont put any oil in the car and the motor seizes, then you would have the jiffy lube insurance be the one to pay for the new motor. and that new motor would still be covered up by the original manufacturers warranty. (make sense?), however, if they install a used motor, which some places have the right to do, then they are the ones responsible to cover the warranty on the motor to the full length of the manufacturers warranty, which for you is fine, until the motor is out of warranty. ]
thus lets say that this happens at 40,000 miles, your hyundai has a 100,000 warranty. they choose to install a new motor (brand new), the motor is then covered under hyundai for the remaining 60,000 miles. Lets say that they install a used motor that has 27,000 miles on it from the same year car, then jiffy jube would be responsible for the warranty until the CAR hits 100,000 miles, but hyundai would be responsible for the rest of the drivtrain. Or if you do not tell the dealer and it goes into service, and they figure out it's not the original motor, then you would have to go back to jiffy lube.
NOW, if your boyfriend changes your oil, and he forgets the drain plug, and he tells you that he can do it properly, and your motor seizes, you are not out of the warranty, your boyfriend is now responsible for replacing the motor and maintaining the warranty until the car reaches 100,000 on the motor, hyundai is still responsible for all the oem gear covered that was not replaced on the car, like the transmission, etc etc.
I do my own oil changes because i am competant to do so, and it save me money because the one time I had it done at a lube place, the synthetic oil change is really really expensive.
