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Which synthetic oil to use?


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this is a bad topic to start here. you'll get as many replies as people really. your best bet is to do some research on the internet or bobistheoilguy.com. or do a search.

 

WIX or purolator for the oil filters for me.

 

definitely avoid Fram, anything but a Fram or a rebadged Fram is fine. some say the higher quality Frams are good, i avoid them all if there willing to sell that other junk.

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It's oil change time. Which synthetic do you guys think is best, based on experience? And what filter is best? I think I've read here a bunch of times that Fram was junk, so I'm curious about what's better.

 

 

I have had great success with Casterol 10w30. I change it every 3k and it looks like fresh oil even then. Doesn't burn or Use any measurable amount between them.

I used to buy after market filters, but now I order from Subaru. They don't cost substantially more, and I have noticed they are heavier and look better made to me, than many after market filters.

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i'd imagine the Subaru filters are an aftermarket filter - just painted for Subaru, it is unlikely that Subaru makes their own. can probably find out searching.

 

here's a link, and i saw others, suggesting that Purolator supplies Subaru with oil filters:

http://www.mindspring.com/~latvia/Other/SubaruOilFilters/Comparison.html

 

it has a comparison and some info on there, with the conclusion being the same i've seen in other tests and repeated across many other boards - Fram's suck.

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If you want a 'synthetic' engine oil:

 

1) RenewableLube bio-synthetic

2) Pennzoil Platinum

 

Oil filters:

 

1) Amsoil

2) K&N (not air, just oil)

tie

2) Subaru

 

The Subaru filters are Tokyo Roki, which is a subsidiary of FHI just like Subaru is. I guess that's the best approximation you can get of Subaru making them themselves.

 

Another good option for motor oil is a CJ-4 rated oil (which is a diesel oil spec) like Shell Rotella T (either the synth or conventional). Mobil's oils are broadly substandard at this point, even in the synthetic and/or diesel lines.

 

My responses are based on oil analysis results.

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I thought about synthetic, but I can get oil from work for like a buck a quart, and it gets dirty just as fast as the $8 a quart synthetic stuff. Yeah it holds up better under extreme conditions, but unless you're taking your Subaru to the Arctic Circle (Or Laramie, Wyoming) or the Southwest in August, or are running circle track with the thing, you probably don't NEED synthetic.

I'd run a good, quality motor oil (I use Valvoline, Castrol, or Mobil myself, and the Super Tech line from Wal Mart is surprisingly not cheap arse junk, plus their synthetic is like $3 a quart if you insist on syntho...

 

My last few oil changes have been with the Mobil 10W-30 we use at work and an OEM filter (I know Purolator used to make the old Subaru filters...) since I get cost + 10% (Although retail is like $6 something) and I've been satisfied.

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If your car has very many miles on it syn oil is really not a good idea, these oils have nothing to help keep your seals pliable, they WILL leak. I have heard Valvoline has a new syn out that has an additive that will work like the conventional oils. ed

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If your car has very many miles on it syn oil is really not a good idea, these oils have nothing to help keep your seals pliable...

Wrong, wrong, wrong! Seal conditioners are a part of every consumer motor oil apart from API SA grade that you can only find in some grocery and dollar stores. Please don't post this misinformation (the part I put in bold). If you've had a vehicle of your own that leaked, go ahead and tell us, but to repeat this flatly false and obfuscatory statement about not having seal conditioners is harmful to the board's knowledge base.

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Wrong, wrong, wrong! Seal conditioners are a part of every consumer motor oil apart from API SA grade that you can only find in some grocery and dollar stores. Please don't post this misinformation (the part I put in bold). If you've had a vehicle of your own that leaked, go ahead and tell us, but to repeat this flatly false and obfuscatory statement about not having seal conditioners is harmful to the board's knowledge base.

 

Well, what he should have said is that synthetic oils are thinner and accellerate leakage/oil consumption issues. That has been my personal experience on multiple vehicles.

 

There is really no argument that a full synthetic oil is superior, but the fact that you can get 250K+ miles out of a well cared Subaru engine using only dino oil suggests that for almost any application, dino oil is more than good enough.

 

 

Nathan

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Wrong, wrong, wrong! Seal conditioners are a part of every consumer motor oil apart from API SA grade that you can only find in some grocery and dollar stores. Please don't post this misinformation (the part I put in bold). If you've had a vehicle of your own that leaked, go ahead and tell us, but to repeat this flatly false and obfuscatory statement about not having seal conditioners is harmful to the board's knowledge base.

 

You my friend will have to put up or shut up, No syn has had these additives until now, why is valvoline making great claims if it is not true. ed

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Well, what he should have said is that synthetic oils are thinner and accellerate leakage/oil consumption issues. That has been my personal experience on multiple vehicles. [...]
Properly classified synthetic oil of the same viscosity rating as "dino" oil is not really "thinner".

 

Previous synthetics did have problems because they were too "pure", and certain seal materials that were designed to swell somewhat in the presence of petroleum wound up shrinking a bit; some current synthetics have more "seal conditioners" (a little "dino" product, etc. :rolleyes: ) to help resolve that problem. Also, since synthetics can do a good job of removing sludge and varnish left behind by previous "dino" oil usage, if that removed buildup was at a seal, it might then leak.

 

A not-unbiased source, but interesting:

http://www.amsoil.com/articlespr/articlemyths.aspx?zo=0

 

Many synthetics are mainly PAO (polyalphaolefin) base stock, with additives. Mobil 1 and Amsoil, for example, have a mostly-PAO base. The other primary synthetic oil base is comprised of esters. Certain of the mostly-PAO oils include some esters. Unfortunately, just because an oil container says "synthetic" doesn't mean it's comprised of mainly PAO or esters; the regulations are lax enough to allow some highly-refined petroleum-based product to be classified as "synthetic" or "synthetic-blend".

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So, what's the final verdict? Synthetic or Conventional? I've been using Synthetic for the past six years or so. And I've used Penzoil and Mobil 1 full Synthetic. Should I stop using it and just juse thicker oil or one that is made for higher mileage cars?

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So, what's the final verdict? Synthetic or Conventional? I've been using Synthetic for the past six years or so. And I've used Penzoil and Mobil 1 full Synthetic. Should I stop using it and just juse thicker oil or one that is made for higher mileage cars?

I say don't mess with Success: Stick with what you have been using.

I use the Castrol part synthetic. When I took the valve covers off, it was shocking how clean the heads were.

Just my 2 cents

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Here's an interesting study which was done over a long period of time on a bunch of NYC taxi cabs,(can't get more extreme than that).

 

In the end, it looks like there wasn't a lot of difference between expensive synth oils or regular "cheap" no name oils.

 

 

 

http://rds.yahoo.com/_ylt=A0geu6MYsylH1t0AirNXNyoA;_ylu=X3oDMTE5dWg0YmoxBHNlYwNzcgRwb3MDNgRjb2xvA2FjMgR2dGlkA0RGRDVfMTIxBGwDV1Mx/SIG=11r1v7jdg/EXP=1194001560/**http%3a//www.xs11.com/stories/croil96.htm

 

If you really think about it....how many people do you know who have had problems due to poor oil performance ?

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[...]If you really think about it....how many people do you know who have had problems due to poor oil performance ?
I know a few, actually. However, I believe that any engine oil that meets the car manufacturer's requirements, changed frequently enough (and in conjunction with a good filter), will probably do the job for the vast majority of us.
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Here's an interesting study which was done over a long period of time on a bunch of NYC taxi cabs,(can't get more extreme than that).

 

In the end, it looks like there wasn't a lot of difference between expensive synth oils or regular "cheap" no name oils.

 

Remember, Taxis actually live a easier life than one would think. While they do idle a lot, they have very few cold starts with rich mixtures which wash oil off the cylinder walls and contaminate the oil. The oil is up to temperature most of the time and there is minimal condensation in the engine.

 

Jack

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You my friend will have to put up or shut up, No syn has had these additives until now, why is valvoline making great claims if it is not true. ed

No, I'm afraid you're in the position of having to prove your load of garbage, not the other way around. No large-scale consumer synthetic motor oil has not had seal conditioners in it since approximately the time they came to the mass market in the 1970s or shortly thereafter. Amsoil is one of the brands originally responsible for the stories of leaks partly because of their diester formulation and the inherent seal-dissolving properties of some diesters and partly because of some of the seal materials used in then-older vehicles, but they switched to PAOs over two decades ago.

 

Valvoline is making big advertising claims for the same reason that everyone else in the market is: to try to get you to spend your money on their product instead of someone else's, and to try to get you to spend 3 times the money on something that only costs them 30% more to make.

 

Someone had mentioned in this thread that synthetic oils are thinner than conventionals, which is also exactly the opposite of the truth, interestingly enough. The primary base oil in a 'conventional' multigrade oil of a given viscosity (let's say 5W30 for example) is actually noticeably thinner than the primary base oil in a genuine PAO 'synthetic,' but the 'conventional' then uses a load of viscosity-index improvers to make it thicken as it warms up.

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If your car has very many miles on it syn oil is really not a good idea, these oils have nothing to help keep your seals pliable, they WILL leak. I have heard Valvoline has a new syn out that has an additive that will work like the conventional oils. ed
Why would you want your synthetic oil to perform like dyno oil?

SOME high mileage engines will leak when changed to synth , cos the synth cleans the crap out of seals. If the engine has been looked after properly, it won't leak.

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Have you ever seen them grooves in a crank where the seals have been riding? Well things dont get bigger as they wear, the seals were kept soft and to a small degree swollen against the crank by the additives in dino oil. Synthetics either didnt have any or enough of this additive to keep the seals swollen. Therefore after so many miles they started to leak. Theory and real life are not related. This forum could not hold the complaints of leaking oil. If you own a Nissan look in your owners manual before changing to synthetic, i have been told that some models they recommend not to use synthetics. [ Have not read this myself]. ed

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Have you ever seen them grooves in a crank where the seals have been riding? Well things dont get bigger as they wear, the seals were kept soft and to a small degree swollen against the crank by the additives in dino oil. Synthetics either didnt have any or enough of this additive to keep the seals swollen. Therefore after so many miles they started to leak. Theory and real life are not related. This forum could not hold the complaints of leaking oil. If you own a Nissan look in your owners manual before changing to synthetic, i have been told that some models they recommend not to use synthetics. [ Have not read this myself]. ed

 

You're absolutely right about things leaking sometimes, ed. You just have the reason wrong. Those grooves are there from either the metal being too soft (rare), the seal material being too hard (also reasonabley rare), the oil allowing deposits to build up and create the scores, the seals aging and thus becoming too hard/brittle and scoring the metal (from, for example, insufficient seal conditioning, excess heat build-up, etc.), or things of that sort. The oil allows deposits to build up and fill areas to slow or stop those leaks. Once they're cleaned off by any means whatsoever, there's too much gap and things leak. In your example, if the engine had been kept clean from the beginning (either from using synth or some other means) then the leak wouldn't suddenly be there; simple as that.

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