Reasons for clean oil?

[bowtieguy]

Originally Posted by maximilian

How do longer change intervals relate to the humidity getting into the oil issue? Since I'm more time than mileage limited, this counts for me more, right?

you may be fine in the north in that regard. just be sure to reach full operating temps regularly if you drive mostly short trips than do not allow it.

and w/ the miles you drive, you needn't change the filter half way as i do.

[bowtieguy]

interesting that Mobile1 scored so low on this wear test. http://www.amsoil.com/storefront/sso.aspx

maybe amsoil is trying to "dog" its nearest competitor.

[dkjones96]

To me, that test is worthless. They are testing Amsoil 0w-30 against 5w-30 for everyone else. You could easily skew a test in your favor doing that. Plus, even the Amsoil .4mm wear on a ball bearing turning 1800 rpm at 80 pounds of load for one hour is crap protection.

The real test is 8 different bearings with 8 different oils run under pressure at 1800 rpm with the recommended viscosity for that bearing for hundreds of hours. Two weeks would make me happy.

The extended performance oil... I can see that being an accurate wear approximation. I bought that oil once and when I put some on my fingers and rubbed them together it wasn't very slick like the normal Mobil 1 is. I gave that bottle to a guy that said my finger test was stupid and he ran it.

[dkjones96]

Read a little more about the 4 ball test they use. The only tests you can really find are for Amsoil comparisons and the test was originally designed for testing grease for extreme pressure metal on metal protection, such as wheel bearings.

[theclencher]

When a car sits a lot, moisture accumulates in the oil. And if it never gets hot, the moisture never burns off.

The moisture accumulating thing is not always true!!!

Here's a good example for ya: I bought a '59 Chevy that hadn't been driven since 1968. Part of those years were in a garage and part were outside. So I start working on this thing right where it sits, to resurrect it and drive it home. I check the oil and what do I see? Nice clean honey-colored oil with no evidence of moisture at all!!! That's 35 years of sittin'! (BTW, I put my first thousand miles on it with that oil and filter, and the old belts and hoses too! AND I'm still running the original tranny fluid. Local trans shop guru told me to LEAVE IT IN THERE!!! He says the old whale-oil based fluids were better.)

If that example isn't good enough, then there's this: I've been driving for 35 years and it was only in the beginning that I followed "all the directions to a 'T'". I discovered that not ALL the "pickling" procedures were necessary for over-winter storage. And I discovered that- in my climate anyway- time limits for oil changes were bogus. I go by mileage PERIOD. Sometimes my vehicles will go for a year or two or maybe even several years before they get an oil change; it depends on the mileage. Nope, NEVER had a problem with condensation or moisture or contamination or whatever it is you guys think goes horribly awry. In case you're wondering, I have one car with almost 300,000m and several others with well over 100,000m. They are all going to rust away into nothing before the engines quit!

I do agree, though, that engines do need to be brought up to operating temp for oil to live. Might I suggest that if your trip is so short that your engine doesn't warm up, that you get off your *** and walk it?

[greasemonkee]

Water vapor is a byproduct of complete combustion, if internal components are cool enough to collect condensate before passing out the pcv system, you'll have water in the oil.

Originally Posted by bowtieguy

interesting that Mobile1 scored so low on this wear test. http://www.amsoil.com/storefront/sso.aspx

maybe amsoil is trying to "dog" its nearest competitor.

This is interesting, I've heard the same thing elsewhere about Mobil1 5w-30, bobistheoilguy forums I think. 10w-30 was supposedly better to some extent.

[Ford Man]

I never have worried about the 6 month time limitation on oil changes. My '97 Escort wagon has 24,xxx miles on it and the oil has been changed 7 times since new once ever 3K miles and the oil comes out looking hardly used. I bought the car new in 2/98. If I'd changed the oil every 6 months it would have been changed 22 times already. I can't see how it can be hurting the oil with the car sitting in the garage. I might be more concered with the time if I were driving it 1-2 miles a day where condensation could get into the oil, but the only difference in the oil in it and what I would pour into it if I changed it is the new oil has been sitting in the plastic bottle instead of the oil pan.

As a normal rule I have been changing the oil in my old '88 Escort with 494,xxx miles every 3K-5K miles ever since I've owned it and it was driven on dusty construction sites for 12 years before I became disabled. I have started changing it every 10K for the last 20K miles since I started using LC-20. That is their recommended oil change interval and I figured I'd never have a better car to try their product on, and see what effect the long change interval had on it. So far I haven't noticed any more oil consumption than when I was changing it every 3K-5K miles. That is the only car that I'm letting go 10K miles between changes though until I see what the long term effects are.

[kamesama980]

basic design may not have changed but metallurgy has changed (stronger metals, different metals) and tighter manufacturing tolerances have developed from increased quality and use of computers/robotics. manufacturing techniques and tolerances that were only possible hand building race engines then are standard for mass production now. what im trying to say is that while the old engines may have all been within spec, they might range all across the range wheras newer engines are all going to be closer to the same spec and closer to the minimum spec.

the 350 sbc might be a 50 year old design but they didn't build it exactly the same way with the same machine etc at the end of it's production.

engines are also broken in more and better at the factory now before even being put in a car than in years past resulting in more cars with better sealing parts. working at a shop doing oil changes, there's a big difference even in the last 20 years between cars with similar mileage 5, 10, 15, 20 years old. I've had hondas from the early 2000s with 150k on them have oil that looked barely used and they're at 5k on the change interval. seen a few that have been abused (hard use before warmup, lots of short trips, etc) that were black as death at that mileage but not like cars from the mid 90s or earlier... some of those are black by 1000 miles no matter what.

[theclencher]

Agreed- engines are NOT the same as they used to be.

Small block Chevys, for example... great design right from the get-go in '55, but the first couple decades the blocks were made of mush. GM did that on purpose to make their machining tooling last longer, but the cylinder bores paid the price. And the tolerances were all over the map.