My oil (Penzoil Dino Oil) has been in my engine for over a year now. It has 1,422 miles on the oil. Oil is still fairly clear, not brand new but not as black as 3000 miles either. Since the past rule of thumb has been 3K miles or 3 months you need an oil change, I was wondering if this is still true? I normally go 6-8 months between oil changes, but always at the 3K mark.
Basically, has this oil broken down enough by just sitting that it really needs to be changed or should I stick with the 3K plan on oil changing?
99 SE with less than 43K on the clock and a few mods......
Rule of thumb has always been 3 mo or 3000 miles. An automotive engineer I once knew said this is true for lots of hard driving but with everyday driving you can go 5k to 6k miles in between. I usually run about 5k miles with work and city driving but 3k if I go on a long road trip or a good off-roading weekend trip. Consumer Reports has also proven that oil from different brands is the same with exception of the detergents each company uses. 5w-30 Havoline is the same as Penzoil and Mobile 1 and .....well, you get the picture. I can't comment on synthetic as I have never used it.
Not to get into an oil debate here, but how would a Pennzoil (Dino juice) be the same as a synthetic like Mobil 1?
Regardless, change the oil and filter, and go on your merry way.
I go 5-6k between changes using Mobil 1 and my engine has never run better. I switched from the regular stuff that had been put in prior to that at 82k with no ill effects (previous owner told me what he used for oil).
I don't know about where you live, but in the south we have to consider condensation. have you ever come outside and there were beads of water on your jeep in the morning, but it hasn't rained? Wel, that happens on the inside too. At least, it does where I live.
If I went a year without changing my oil, I'd probably have several ounces of water in it by that time.
Change that oil! A year is far too long to leave it in there.