The owners manual in my 98 Benz recommends every 12 k miles under normal conditions, and does not specify synthetic oil.
I have always stuck to the 3 in 10 principle, maybe its time for 2 in 10.
I did put synthetic in the Benz, the Honda has almost 3 k miles on it's last change and the level is exactly where it was when it was changed.
The Benz has a tint on the aluminum surfaces that are visible under the oil filler cap, while the Honda looks perfect.
I have seen perfectly clean, perfectly running Nissan engines with 500k miles on them. That would be 166 oil changes at $20 each at Wally World or about $3320 for oil changes. Done every 5k would save you 66 changes or $1320.
Synthetic is not much more in price than dino. I just bought a 5 qt jug of Valvoline Syn in wally world for $20. A 5 qt jug of Valvoline dino was $13 I think. If you buy syn by the quart it is more expensive so buy the 5 qt jugs. It has better lube qualities and you can use a little longer change interval. I didn't notice any real measureable difference in fuel economy when I switched to syn as I thought I might. But I still use it for the reasons I stated.
anyone remember the toyota engine sludge issues? not going in to detail on that but i will give my experience:
having lived only in florida, i have seen first hand the sludge issues with a variety of vehicles, and more importantly the lack of sludge using TRUE synthetics.
you guys in cold climates may not see this(hot weather related sludge), but PAO based synthetics have been found to have THE lowest pour point to cover the other end of the perspective.
there are too many variables(type of oil, length of change intervals, driving conditions and style, climate, etc) to calculate accurately the cost difference. if you calculate extended intervals it would be at the very least close, with the extra being "labelled" as insurance, if you will.
i have a saying that goes "i'd rather have it and not need it, than need it and not have it."
so far i'm quite happy, getting roughly the same mileage out of my second tank on synthetics. i'm just going to keep an eye on it and see how the oil dirties up and see if i feel comfortable with an extended drain period.
a little tip for you guys - if you want a really good oil filter grab some old strong magnets and stick them on the sides of the filter. a dead hard drive is ideal for this. its not to improve fuel economy or anything like that. the idea is that small ferrous particles that get into your oil that your filter might have trouble with get stuck on the walls thanks to the magnets. either way, can't hurt.
Hard drive magnets are extremely strong and you don't have to worry that they'll fly off and land on something sensitive, but their field doesn't reach very far. This means they'll only catch particles that pass within maybe 1/4" of the magnet. That might be good enough, since any given particle is bound to pass through the filter repeatedly, but it's food for thought.
I've been buying magnetic oil drain plugs for years. They only cost a couple of bucks, and its easy to clean it when you change the oil. With each progressive oil change with synthetic you should go farther & farther before the oil starts looking "dirty". The synthetic should be slowly cleaning out the engine. I replaced the engine in my Buick ~ 12 - 14 years ago and have run nothing but synthetic in it from day one on the new engine. From what I can see looking through the oil fill hole it looks exceptionally clean in there.
When I replaced Rusty's timing chain this past spring the inside of that engine looked really clean too. Looking up at the crankshaft from underneath it was so clean it almost looked like new, and the engine had 190,000 miles on it. Rusty has been on a diet of synthetic for the past 40,000 miles (8 oil changes)
The oil never turns black in any of my vehicles. Most often it will come out after 5,000 miles looking like a dark honey color, sometimes maybe the color of pancake syurp, but its always still translucent.
Hey dkjones96 that cylinder looks pretty bad - after you hone it out near the top I would be interested in knowing how much wear is there at the ring steps.
The point of the Synlube is that it doesn't turn to sludge like the oils you all are using. Granted the engines today are built better than 20 years ago - keep in mind that I keep a cars for 12 years or more at a time. My xB has been on Synlube for 19235 miles and I only added about 1 cup of Synlube after about 1 year to bring it up to full from the initial filling which wasn't quite full (1/8" from full) and now it is still full after almost 20k miles. Nothing wrong with taking some business away from the oil companies is there?
So "somedude", it seems to be working for me is all I am saying and it sure is nice not having to deal with changing oil and figuring out where to recycle it myself. Funny thing is I stopped by the Toyota dealership to get my Touchup paint and asked why they had so many stalls in their massive garage and the guy replied . . . for oil changes. I just walked away chuckling.
JanGeo, how does the cylinder look bad? We cleaned off the buildup at the upper part of the cylinder and it felt smooth all the way down. What you see at the top was just carbon buildup where the rings don't scrape. We aren't doing a hone on it because the bottom end isn't getting torn down. It seriously doesn't need it. It's within 5psi of factory specs for compression.
If I was going to rebuild that bottom end I could just re-hone that cylinder and use OEM spec rings in it. There is THAT little worn away.