SL synthetic or SN semi-synthetic, which is best, normal service
- Thread starter 100td
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Use the old stuff first, SL has been obsoleted for nearly 2 decades
Yet some of the best modern oil like Castrol euro 0w30 are SL spec.
If this is oil you have in a stash, use the oldest oil first.
New or old. There are a lot of SL rated synthetics that are typically high end euro oils that are just skirting compliance but still show stringent approvals. Castrol edge euro you can get at walmart is an example. A lot of the 40 grade SN euro oils did transition to SP since SP phosphorous limits don't apply to 40+ grades. The 30 grade euro oils still tend to have the older standards like SL an SN.
Euro being Euro the acea spec that it has is what matters most for the oil. This is an acea a3b4 so not that modern a spec either. Well formulated oil certainly but for older cars.
I wasn’t slamming SL, Trav… I saw the OP is Down Under, and yes I know several Euro specs still meet SL because of additive levels. I use some myself.
With the info that the OP’s engine could use either spec, I recommended the SL because we know the add pack should more closely maintain what the engine originally saw.
Brevity is sometimes my enemy
(Deleted double post)
Impossible to determine; you haven’t shared make/model/usage or oil brands of the two choices…
But the short answer is if your engine requires SL or older oils and is not a flat tappet cam, either one will protect as well or better than your vehicle manufacturer originally required.
All depends what you plan to put the SL oil in. It is not recommended for many late model engines. SL would work fine in an older engine.
No, no I didn't think you were. I have no idea why they are still developing higher end new oils with the SL rating that's all.I wasn’t slamming SL, Trav… I saw the OP is Down Under, and yes I know several Euro specs still meet SL because of additive levels. I use some myself.
With the info that the OP’s engine could use either spec, I recommended the SL because we know the add pack should more closely maintain what the engine originally saw.
Brevity is sometimes my enemy
It seems a little strange that on Suby EJ engine they spec SL up to and including 2006 and SM 2007 up to 2014, the engine internals are identical in clearances and materials with the exception of valve adjustment systems that all appear throughout all the years.
Exactly. I use SL oils in my 07 Impreza with no worries, which is at 187k on original HG. I’ve used 0w30 thru 15w50 and it just doesn’t care.
ACEA A3, B4 and API SN are very basic requirements. The lubricant will meet or exceed these requirements.
SN has improved deposit control over SL, but I might hazard a guess that the synthetic would outperform the newer SN spec lube here. All depends on formulation and the motor it 's in and the way that it's driven.
You can look at specs all day long, but like buying Stereo equipment, you don't know what you bought until you listen to it. Do you own either oil, have you run either oil in the past?
- Ken
Synthetic is a nebulous term these days
Does it matter if the vehicle(s) in question spec SL conventional ? SL synthetic, SN semi-synthetic, and so on may be "better" than what the engines want to use so no need to overthink this. Use up the older oil like others have said.
There is no best.
Either will work fine for a normal interval and you will notice no difference in engine performance or engine life.
Either will work fine for a normal interval and you will notice no difference in engine performance or engine life.