Yea 3k 3months is not the way to do it. If you must change the oil only once per year at least do it right before the "driving season"

Has anyone here done a before and after dyno test of switching to full synthetics? In a mustang magazine a few years ago they took a 100k mile mustang GT and switched it over to mobil 1, it gained around 4-5hp from switching to synthetics.

If the car is not a DD I would go with months instead of miles.

Dino engine oil is not as hygroscopic as synthetic oil. Regardless, the amount of water absorbed by the synthetic oil won't do any harm such as corroding the engine's internal components to the point where it will fail as long as the oil is changed on a regular basis, even if it's yearly for synthetic oils. That said, then why not just use dino oil that doesn't readily absorb moisture? The oil debate is over stated because even the cheapest dino oil that truly meets API specs will effectively lubricate your engine under normal use and when changed regularly will probably outlast your ownership of the vehicle. Car manufacturer's want you to change your oil more frequently, at your expense of course, as a little bit of reassurance that the engine will not fail prematurely and avoid a warranty claim as well as make more money for the dealership's service department. I doubt there is any scientific evidence for engines lasting any longer by changing the oil more frequently but members here are welcome to present the facts otherwise.

I once owned a plain jane '67 Camaro that sat in an unheated garage in Newfoundland, Canada (all kinds of moisture laden air in that place) from 1981-1983 with used dino oil. Started her up and away it went. The only damage caused by neglecting her for two years was the valve seats dried out and cracked. I know this is not scientific but based on that experience I don't waste my money on specialty oil companies such as Redline, Amsoil, Royal Purple, etc as there is no added protection or proof that will make my engine last longer or perform better for the length of time I will own my vehicle. Now if I raced my car and 1/4 mile or lap times were reduced solely on the type of engine oil then I would use the specialty oil. So, ask yourself this in your decision to buy oil - do all NASCAR team owners use the same oil? If they do then I'll buy that brand because it's obviously the best out there. If not, then it really doesn't make a difference what oil you select especially for normal street use.

I for one will save my money and change the oil according to the manual for my type of driving i.e. every 7500 miles. When the vehicle is out of warranty it will be once a year with synthetic provided I don't exceed 15000 miles or so.

If this is true, then why are some new autos delivered and sold with Mobil 1?

The debate will rage on and on, with "tests""and "proofs" from both sides. I just don't take any chances with my beaZt: Only synth' oil goes in her. Since I've had such a great experience with Mobil 1, I'm sticking with it, not only 'cause of its "proven" qualities (here we go again!), but because it goes on promo' more often that any other brand, and I can get it for $4.95/bottle. Until I experience sump'n different, it's 5W30 Mobil 1 for my monZter!

I do agree. I would say twice a year. Only reason I know is from the fire department, where we purchase the actual 55 gal. drums of oil. Those things have been sitting around for years, and we still use them on our rigs. Keep in mind, our application is usually much more intense than the average Z driver... Start up and run them hard, and shut them off. Granted, you probably wouldn't want to treat your Z like we do to the fire trucks, but you get the point, heavy abuse, and old oil have yet to make any type of signifcant impact!:tiphat:

The offical oil of NASCAR is Mobil1! Simple choice!



(yes, I know it doesn't mean squat to what's used, just making a joke)

Because the oil company wants to tie up with the car makers,like Ferrari with Shell..

Wow, I always thought it was because Synthetic oil is extremely shear resistant, but I could be wrong!

For me its every 5k miles or twice a year.

The oil doesn't break down it gets moisture in it. Take a jar and some oil and water and shake it up. Emulsified oil doesn't lubricate well. I think the basic point here is if you drive 2000 miles a year you still need to change your oil at least once a year but most would recomend twice.

It all depends on the conditions but the worst is on cool days and short trips where the temperature doesn't get hot enough to drive the moisture out. If its sitting in a garage out of the elements its going to have less moisture than if its taken to the grocery store to pick up some milk (unless the grocery store is in the next city). Condensation is also going to be a problem in those same conditions.

For me I only put on about 5K miles on my hobby cars driving in light traffic so once a year on M1 silver cap is more than plenty.

Oil Life in Months or Miles?
 

If one doesn't put many miles on a car in a year, is it safe to run synthetic oil based on mileage instead of months? Thanks!

In aircraft we use hours of usage as the main measure for maintenance rather than flight miles or time after last installation/rework. If needed, the maintenance intervals in hours are increased or decreased to suit the level of severity of typical usage for that aircraft.

I've often thought of using running time on the Z to measure oil life rather than miles--highway miles are easy on the car but make it look like maintenance is needed right away if you use that figure. On months, you may want to ask Bob the oil guy or another expert. I would figure a year or two wouldn't hurt the fluid, but that's a pure uneducated guess.

The goal is to change your oil and filter out before the oil becomes ineffective as an engine lubricant/etc. The maintenance schedules given to consumers are conservative because people don't follow them terribly closely and they poeple doing the recommendation have to assume a usage spectrum that covers everybody.

If you really want to know a hard and fast rule, look into what breaks down, get an oil analysis of your used oil, adjust your cycle, and then get a second oil analysis to confirm you're good to go.

IMO it isn't worth the battle with Nissan if someone happens to your car. $40-50 every three months isn't a huge setback for most people. Can you extend it to 4 or 5? Sure but if something happens to your engine there is a descent chance Nissan will want records of your oil changes to warranty and that might come up.

Warranty aside, my Chevy Trailblazer specifically said in the manual to change the oil either when the oil life monitor said to, or every year, whichever comes first. It did hold 7 quarts vs our 5 though.