I hope everyone had a great holiday!

I'm looking for opinions on changing your oil based on time vs. mileage and would like to know what you folks think. With the additives and cleansers in modern premium oils, do you feel it is necessary to change oil at 3 months if the oil is only 1000/1500 miles old?

I am asking about dyno oil (Castrol) because it's what I use in my cars, but wouldn't mind hearing opinions about synthetic too.

 

I change my Mobil 1 in my truck at 5000 miles. Last time it took almost a year to get that many miles (it's not my daily driver obviously). I figure if the truck is just sitting there it is not getting the oil in the pan dirty, and hopefully no moisture is getting into the oil lol.

Rob

 

Generally I run havoline 10w-30 in my T100 (3.4L V6) and I change mine approx every 3-5k depending on when I get around to it.

Modern dino oils will last alot longer than the old 3 month 3k myth they used to rant about.

 

The Synthetic oil manufacturers that recommend long interval changes usually spec (say Amsoil) XXX miles or one year, whichever comes first. In my GM's company van owners manual it spec's that if the service light doesn't come on, you still need to change your oil once per year at the minimum. Therefore I would probably go with oil changes at least once per year if you don't reach your preferred/spec'd mileage for an oil change.

 

once a year oil changes?! i hope i never buy one of your used cars. do you work for bmw, lexus, benz, etc... and are responsible for the marketing on how low your operating cost is annually b/c you never have to change any of the fluids except your oil once per year? lol...........just playing with you but seriously......

i'd do it at least once every 6mo regardless of how many miles are on it. if you drive it regularly, again no matter how many miles, i would not go over 4k, regardless what oil you use. if its not a new or brand new motor i would not use full synth either. i think more frequent oil changes are better then running synthetic for 6months or 6k anyways.

my speedo is broken and odometer so i try to do mine every 3-4 months as its my daily. BUT, i didn't realize that this summer i did prolly around 7-8k in about 4 months or so! damn.... so, if you go by months try to keep some sort of mental track of milage too.... your 3-4k miles could come up a lot quicker then 3-4 months! i prolly should have been doing an oil change every month or so the way, where and how much it was driven!

 

i doubt you are going to get a solid answer to this, unless somebody with some real knowledge steps in, but here are my two cents. if my cars/trucks didn't see the mileage that they do, I would be prone to changing the oil every 6 months.

supposedly, the problem with letting your oil sit around is that the stabilizers will break down, and become acidic, leaving you with the possibility of corrosion. i don't know how much truth there is to that, and how much of it is hoopla. i drive my cars enough to where the mileage hits well before i am concerned about breakdown of stabilizers.

 

I think what he was saying is that if your put synth in that is good for 5-6k and you only drive it 600 miles you should still change the oil at least once a year, even if you did not reach the recomended oil change milage

 

Use synthetic oil. Its the best value despite its initial cost. You can run it much longer, it will protect your engine better and it will not develop sulfuric acid in your crankcase like dyno oil will do. For example, my sister put 30,000 miles on her last Mobile 1 oil change. Yes, the oil was really black and starting to thicken but the Honda engine still sounds great and uses no oil! Something, by the way, I do not endorse.

My $0.02

 

You didn't read my post. RE-READ IT. I said VERY SPECIFICALLY at the end that: "Therefore I would probably go with oil changes at least once per year if you don't reach your preferred/spec'd mileage for an oil change."

What this means, is if you do oil changes every 3000 miles typically regardless of time, that in a year if you only put 2000 miles on your engine, you should change it out once per year at a minimum instead of waiting until the 3000 miles. Now if you drive more than 3000 miles (or whatever your target oil change interval is - for some it's 3000 miles, for some it's 5000 miles, for some it's more) in a year and 3000 miles is your oil change interval, then obviously you will be changing it sooner than annually so it's now based on mileage, not per year. The bottom line is to not leave oil in your crankcase longer than a year if you don't drive more than a standard (again say 3000 miles) oil change interval or whatever your preferred your engine's recommend interval is mileage wise.

Personally, I go based on mileage because I've never driven less than 6000 km's (about 3500 miles - my oil change interval) in a year with the driving I do. It usually works out lately to about 2 oil changes per year. I run synthetic oil (Mobil one since I've owned it with the exception of one Amsoil change - switching to Amsoil oil religiously soon here though) and just change it out every 6000 km's or so.

Synthetic oils can be run MUCH MUCH longer but since I own an older engine I won't run it longer as I want the increasd additives to deal with any blow by or contamination (as I'm guessing my seals aren't perfect - I don't have any leaks though, I fixed those a several monthes ago) from synthetic plus I like having much better oil.

If I had a new engine I would probably bump up my oil change intervals to 8000 to 10,000 km's (about 5000 to 6000 miles) with Amsoil synthetic oil. These oils can be run and are advertised to run much, much longer than this too if need be, and many of the general public is brainwashed into 3000 mile oil changes. Maybe if you run regular mineral oil but not synthetic.

For the record, you will not find a vehicle that has been serviced more religiously or better than a vehicle I have owned. You could only wish you could find one like mine if you went searching for my model of truck.

 

The only time I followed the time versus mileage rule was with my Pontiac musclecars, they had very expensive engines that made me a bit more anal about my maintenance.
Three of them were also set-up for nitrous with hidden systems, due to that I could not run a second fuel delivery system so we had them tuned to run "rich" so when I hit the "go" button they wouldn't grenade. Due to that I would get fuel in my oil, apparently quite common if you run overly rich, fuel seeps past the rings no matter how good they are(even moly rings), therefore my oil, as I was told, was prone to "breaking" down quicker and thats definitely not good.
I have worked on alot of older cars and have a very extensive factory mechanics manuals collection for older Pontiacs (60s-70s) and something I have always noticed is if you follow the "factory" tune, its mostly on the rich side up until they had smog equipment, then its mostly on the lean side.
I sometimes feel that the automakers and such just don't change or update their point of view, which seems to be the case with things like oil changes.

 

Thanks for the feedback.

I have heard this too and was wondering if it was based in fact for modern engines and oil or just something that the guy tells you while he is trying to sell you muffler bearings.

I have heard many more people say the mileage is what is more critical and that it is typically safe to switch to a by-yearly or yearly schedule if the mileage limit is not met. Factor in driving conditions, environmental conditions, etc. etc etc...

 

If my truck had a 1000 miles on it in one year using syn oil I'd still change it at the end of that year.

 

Here is a great piece just about oil in general. It's a long, probably an hour, read but is worth it.

http://ferrarichat.com/forum/faq.php...tor_oil_basics

I try to keep it changed every 3k miles but I honestly don't see any trouble with doing 5k miles if you don't do severe driving. I want to say from what I have read on a quart of oil one time is says 3000 miles under extreme cases.

I've got 150k miles on 3.4 4runner. I've had if for 2 years and 40k miles. Doesn't burn a drop of oil or anything. Like I said it usually change it between 3-4k. I also now use Lucas Oil Stabilizer. I started running it in my Probe, 178k miles on a 18 year old turbo engine, and it stopped the little oil burning it did.

 

I do 4k miles or 12 months. My 4Runner usually only goes 3500/yr. Generally that equates to an annual oil change.

 

Ya, I agree. I used to have a Ford Lightning which was driven about 1500 miles per year, and my current BMW only gets about 1500-2000 miles per year. I change(d) the oil every 8-10 mos. My 4runner, which is my DD gets changed every 5K.

 

This type of post ALWAYS seems to piss people off on all sides of the issue.

Here is what I do with my 99' SR5 4 Runner 3.4 that by the way, purrs like a kitten....at 145K
Oil changed every 8,000 to 10,000 Miles with Mobil 1 Extended Performance 5W30 ..as this stuff is Bomb proof and can hold up to hellish temperatures swings (hot and cold)
To the nay sayers out there, and I know there are many: Synthethic oil is lab and track tested to hold up, and go the distance and this is not myth, this is a fact and I always verify further and back it up with oil analysis every 10K I will post the results shortly.

Ice runner over and out.

 

I just change mine when it gets to that certain colour/thickness....usually around 3500km. I don't go by any time or millage date.

 

Thanks for all of the info.

Not my intention. I just wanted to find out if there was any known danger of loss of viscosity by leaving the oil past the three month date.

It doesn't sound like anyone knows of one.

Thanks again

 

3500 km is only ~2200 miles.. you're wasting your money no matter what kind of oil you're using.