Synthetic oil and change intervals

[Spector]

Ralph:

granted keeping the oil clean is a major factor, howevr, assuming that you can keep dino and synthetic clean I have to disgree with you, synthetic can go significantly longer between changes. Just my opinion based upon too many years of using both and oil analysis

 

[zzdroptop]

quote:

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Originally posted by Spector:
Ralph:

granted keeping the oil clean is a major factor, howevr, assuming that you can keep dino and synthetic clean I have to disgree with you, synthetic can go significantly longer between changes

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I have to agree with spector here. Keeping the oil clean is the trick....synthetics will last much longer than the dinos but both get dirty at about the same rate. You shouldnt have a problem getting 6000 or more miles out of a synth. but change the oil filter every 3000. (use a quality filter such as Pure 1,or Mobil 1). As for me I use Amsoil 15w-50 and Mobil 1 filter in my Z28 and change both between 3000 and 4000 miles...My car sees 6000rpms quite often so its cheap insurance IMO. I might add that I use dino in the minivan and change every 3000 to 4000mi also. Different apps have different needs.

 

[widman]

I don't agree with changing the filter more frequently than the oil in most cases. Especially with a Group II, III, or IV, since the oil's ability to not raise pressures is dramatically increases with the better oils over the Group I. Chevron has some graphs in their base oil pages that show this.

 

[Bror Jace]

What widman said is worth considering.

Also, those of use who used to post on Edmunds knew Tom (Tsjay) who worked in the filter media industry. He stressed to us numerous times that even cheap filters are seriously over-engineered and plugging up a filter while following even a halfway responsible change interval was nearly impossible.

With the change intervals I feel comfortable with (7,500 miles max) I'd never bother again with just an oil filter change halfway through my interval.

--- Bror Jace

[ August 12, 2002, 10:30 PM: Message edited by: Bror Jace ]

 

[Patman]

What if your car used a really small oil filter though Bror? I can say I feel comfortable leaving
my Firebird's oil filter on there a long time, since it's so huge, but I don't quite feel as good
about doing the same with my wife's Honda, since that filter is about a quarter of the size of
the Firebird's. That's why I want to run a longer filter on the Honda.

 

[Spector]

Although the filter will probably not become full etc. in 10,000 miles the problem I have is that after about 5 months the drain back valve/gasket begins to fail and leak back oil. I have noticed this in my Amsoil filters and this may be the only reason to change a filter at 6 months or less. Perhaps that is why Amsoil also says to change at 6 months regardless of mileage.

Now, if the filter is a vertical mount it may not matter. Even with a faulty drain back it may not matter either, what's a second or so.

 

[Bror Jace]

Patman, how small is small? Most good oil filters for the Civic are not that small. If you've told me what you use, I've forgotten.

Spector, good point. Fortunately, I've never gone over 5 months.

--- Bror Jace

 

[Patman]

quote:

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Originally posted by Bror Jace:
Patman, how small is small? Most good oil filters for the Civic are not that small. If you've told me what you use, I've forgotten.

--- Bror Jace

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The filter on my wife's Civic is the same size one that goes on yours, as the Purolator
catalog shows that all the 95 Hondas used the same filters as the 2000s. Next time you
go into a parts store, pick up a PF35 AC Delco (or L30040 Purolator) and compare it to
yours, you can see how much bigger it is. I just checked these filters and compared and I
was a bit off on the size difference, but the Firebird long filter does appear to be way more
that twice the size of the Honda filter.

One thing I don't need to worry about is having the bypass or antidrainback valve stick on
my Firebird filter, as it has neither of those features. So I can run it to the full mileage I want
no matter how many months it takes, and won't have to worry about having these things
stick on me.

 

[jason07-1zzfe]

quote:

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Originally posted by Bror Jace:
...He stressed to us numerous times that even cheap filters are seriously over-engineered and plugging up a filter while following even a halfway responsible change interval was nearly impossible...

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That may be true, except for Fram. There is an analysis on maxima.org where they went over 3k with a Fram and the wear metals went through the roof. Who knows if it plugged (likely since they contain significantly less media), or just had leaky valves or that carboard garbage wasn't sealed or fell apart.
We may never know much more since anyone that is interested in thier car enough to do analysis is smart enough not to run that junk.

Patman, About the bypass, do you know how those work? Do all GM's use them? If one on a filter could stick, doesn't it stand to reason that one built into the engine could, and that sounds like a lot more serious problem and more hassle....if you ever found out.

 

[BOBISTHEOILGUY]

quote:

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Originally posted by **** '97FLHRI:
Is there a section or tutorial on oil analysis on this web site? To use oil analysis for decision making,

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Yes there is,

At my home page http://www.bobistheoilguy.com I have many different sections that answer a lot of questions as well as a lot of refference material.

The oil analysis section covers everything from history of the analysis to what each part of the analysis is showing you. It is not hard reading and in very simple terms as I do not like to assume everyone is up to speed about oil.

Here is the direct link to the oil analysis section..
What is Oil Analysis

There is a special section about silicon that is located about mid way in the page, dont miss that as it gives you some excellent info on what it is and how it affects the oil and wear. In case you miss the link here it is.,

More on Silicon

Hope that helps

 

[MolaKule]

Jason,

I have never heard of an engine bypass valve failing. It is built upon a fail-safe design.

However, I suppose if the oil were allowed to sludge and coke, the steel ball might not be able to move from its position and fail. But then again, the engine has probable failed already or worn to the point of replacement or rebuild.

 

[Patman]

MoleKule, would you happen to know approximately when that built in bypass valve in my engine might open? Are all GM's set the same way, or is it different between the V8s and V6s?