FAQ: Engine Oil - What type and change intervals?

SilverArrow102 wrote:

Quote :

Even if the oil doesn't break down, there's always the chance that some foriegn matter, debris, metal from engine wear, etc. could get into the oil and cause damage, especially if using aftermarket internal parts. You just never know.

You're directing your worries to the wrong element. True, foreign matter, debris, metal from engine wear does get into the oil sythetic or not. The FILTER is the weak link in the chain, not the oil. Use quality filters and you won't have the debris floating around the oil. Stay away from FRAM... if you use it, your just as good off using no filter. Fram is junk.

Synthetic oil does not break down like petroleum based oils over time and use. Syn oil also lubricates engine parts faster during cold starts when most damage is done. If you're unwilling to do oil changes in excess of the 3k mark, don't use syn oil. Even cheap petroleum based oil last that long.

Numerous tests have been done on synthetic oil and petroleum oil and the proof is in the pudding. Syn oil is hands down more effective in protecting your engine from wear. It's the filter that determines for how long and how well.

Good to know!

quote: "If you're unwilling to do oil changes in excess of the 3k mark, don't use syn oil. Even cheap petroleum based oil last that long."

This was really the point I was trying to make. People put in synth and the bottle says to run 15k miles before changing. Even if the filter is supposed to keep all foreign matter out of the oil, I don't like the idea of using the same stuff for that long. Does the filter protect against foreign liquid contaminants such as antifreeze?

Cheaper oil does the job for as frequently as I change it.

Quote :

Does the filter protect against foreign liquid contaminants such as antifreeze?

If you have enough anti-freeze in your oil to significantly contaminate it, your problems are much worse that what oil or filter you should be using.

Virtually all of my miles are on the highway. I change the oil, rotate tires, and run injector cleaner every 6k miles.

Well of course an oil manufacturer is going to sway the facts to get you to change the oil every 3k miles! They'd be going out of business if everyone changed at even 4k miles.

It's a no brainer that oil picks up contaminants and suspends it thus circulating it all around your engine. That's why you must use a good filter, NOT something like a Fram! If you use a Fram filter, you might as well use an empty can for a filter.

The '01 Cadillac ElDorado with the touted 300hp Northstar V8 we owned had a FACTORY recommended oil change interval at 10k miles! Okay... it came with Mobil1 and that was recommended as well but gee... it's oil and picking up the same contaminants as any other motor. What's the difference then? 10 qts of oil and a bigger oil filter. Still, same oil, same contaminants and the motors go for 100k miles before a FACTORY recommended tune-up and with reasonable care, run for several hundred thousand miles.

I personally do not care for Quaker State oil, aka Caker State. Seen several cases of massive sludge build-up in motors that devotedly used Quaker State. Could have been due to poor maintanance, poor filter choice, harsh driving conditions but still.

I use Mobil1 synthetic oil or Havoline full synthetic in my vehicles with a high quality filter like K&N, AC, Wix, etc. NEVER Fram. At between 3k and 4k miles, I drop the filter and put a new one on the top off the oil. At 5k miles, the oil is still clean and honey in color. At between 7k miles and 10k miles it gets new oil and new filter. I've never had an oil related breakdown and have run my vehicles to well over 150k miles as daily drivers.

Bottom line, the oil manufacturers don't want you to believe for 1 second that you can go further than 3k miles between oil changes. Why would they? They would rather you be paranoid that it will cost you thousands of dollars in repairs if you didn't believe them. Besides, you would be taking money away from their profits!

I run Shell Rotella Synthetic 5W40 and a Purolator Pure 1 in everything but my higher mileage cars - Which get Rotella 15W40...

There was a forum I used to frequent that rates Rotella as the best overall synthetic oil simply due to price, high detergent content, etc.

I used to use Shell X100 oil, quite a few years ago, because the tests showed it would not break down as much as others. Back then, and maybe now, it was the only oil that was not made from PA grade crude oil?

quote: "At between 3k and 4k miles, I drop the filter and put a new one on the top off the oil. At 5k miles, the oil is still clean and honey in color."

Can you just pull the filter on our engines without losing oil? I've always drained the oil beforehand, because I thought it would just spill out if you removed the filter first.

AA wrote:

quote: "At between 3k and 4k miles, I drop the filter and put a new one on the top off the oil. At 5k miles, the oil is still clean and honey in color."

Can you just pull the filter on our engines without losing oil? I've always drained the oil beforehand, because I thought it would just spill out if you removed the filter first.

You will lose what is in the filter and a little more, probably between 1/2 and 3/4 of a quart or so.

im only posting this hear so i can get a quick answer ,im going to be running royal purple. but should i run 5w30 or 10w30

The quick answer is 10w30.

thank you sir

Except that the manual says to run 5W30 in colder regions in winter, I don't have the specific temp range in front of me. I've just changed from RP 10W30 to RP 5W30 for winter. We see lows hit -20 to -25 at times in Dec-Feb, so it's going to turn over easier at those low temps. I don't know how cold Utica gets in winter... My Riv is in an unheated attached garage, but sits outside during work hours. I'll try to get thru February on this oil change, then go 10W30 again for spring/summer/fall. In NY, you are probably OK going either way, but I'd lean to the 5W30 myself for winter.

Aaron, is your Riv parked for winter, or a year-round DD?

Year round driver, never seen a garage. Perfect starts with 10w30 in temps as low as -10F.

I agree, there won't be a starting problem with 10W30, just that for a very cold start, the engine will turn a bit easier with 5W30, and oil will circulate a bit easier right away. -10 is nothing...

The manual recommends using 5W30 for expected temps below 60deg F, for reference. (just looked it up)

Hmm. Good to know.

I was very surprised to see the 10W30 label on the oil cap when I first opened the hood.  I thought just about all "relatively" newer cars defaulted to 5W30.

But then again, the 3.8/3800 is an old school engine, probably with looser tolerances than more modern designs, thus needing a bit heavier weight oil for normal operation.

well im in NY so should i go with the 5W30

In NY I'd run 5W30 during winter months, 10W30 spring/summer/fall.

Being multi-weight oils, they have identical properties at operating temps (30), but the 5W flows more freely then the 10W in cold temps. At least that's my understanding of the ratings numbers.

I run 5w30 most of the year. The summer months I run 10w30. I'm in Mass.

ok thanks man

What is the drawback of running 5W30 in the summer?

I suppose the lighter oil in summer temps would tend to drain down more instead of clinging where it is needed at startup. No diff at operating temps though.

we run 10w30 in my moms 02 aurora and and my bros 95 aurora (i hate both of them wish theyed sell em and get buicks) i figure ill run the same in my riv