I have a drum of engine oil labelled SG 10-30W. According to Castrol I shouldn't use category SG in engines newer than 1993, I should only use SL in the newest engines---but then they want me to buy more oil. Does anyone know if I could use SG in current engines?
Colin
I've had the same dilemma quite recently and asked a mechanic friend to explain it to me. The story is that newer engines are set-up not use as much lead additives than older engines and that older types of engine oil have high lead content. Because of this, the materials that make up the rods and piston parts don't take to well to high lead content and can actually rust more quickly.
Well that's how it was explained to me anyway.
That is truly bizarre. Nothing I've ever read about engine oil, and no lecture I've ever sat through on the subject has ever indicated that lead was ever used as an oil additive.
Can anyon else confirm this?
That's just BigWallop away with the fairies yet again
SG is fine. It won't last as long, and it's probably made from recycled oil rather than fresh synthesis, but it's a perfectly good lubricant.
The problem is that it doesn't meet emissions regs for California, where type approval (not even the annual inspection) tests a few more emissions than we usually do here. This is mainly due to unrefined recycled crap, rather than the SG rating itself. As such, a blanket ruling is simplest for the oil companies. 10-30W SG must be a few years old though ? I've only seen it as 20-50W recently, sold for oil-burners with no rings or valve guides.
In '97 I was looking for SJ rated oils and simply couldn't find them anywhere. In the end I found one dealer in the whole city who knew what I was talking about, knew that the S* rating system went beyond SH and stocked some (Valvoline). Now you can hardly buy anything of lower grade than SI, unless you go to Wayne's Escort Emporium in pikeyville.
I wouldn't use it in a turbo though, because of the coking problems.
First I've heard of it too. Also, to the best of my knowledge there's been no change in piston or bearing material of any consequence.
However, I'd stick to the recommended oil. If it's an old car from when the oil was current, then perhaps ok. But on a newer car with extended oil changes it's really not worth the risk - oil is a tiny cost in motoring.
I remember someone posting a URL which explained all the various classifications of oil. These are not defined by the maker, but by independent bodies and sometimes also individual car makers. I've got this one bookmarked under oil, which may explain some things.
Was that realy necessary? It has already been established that there are "thieving pikey bastards" on this NG.
Steve R
Maybe not necessary as such, but certainly amusing.
On the contrary. Molybdenum yeas, lead? Never heard of it.
>
And in a fllod of gebnerosity and political correctness, IMM is allowing them planning permission to park trailers in his back garden.
Well not me. By "pikeyville" I was thinking of Kingswood (where you can barely park a bike, let alone a trailer).
Correct! How did you know? I'm planting the mines now.
I don't know how old it is. It came with the house! I have various drums and containers of oil, the SG, some chainsaw oil, some diesel engine oil. The latter is the only one I know I can use, in the diesel generators. The chainsaw oil can be used on bicycle chains though opinion is divided on its usefulness. The previous occupants had older cars/motorbikes and so they may have used the SG on that though it is in the generator shed rather than the garage.
Now, the one thing I have learnt is that category SI doesn't exist, they (the SAE) went straight from SH to SJ to avoid any confusion with the SI of SI units.
Colin
I have never heard of this. It is quite possible that when leaded fuels were used, some lead got carried into the oil via blowby. Perhaps there is some confusion with zinc dialkyldithiophosphate which is being cut back because it shortens the life of the catalytic converter. In theory of course, engine oil won't get into the cat, but there is a degree of two-way transfer between the hot side and the oily side of an engine. The bigger oil manufacturers do a service for fleet owners where they analyse for metals to pinpoint imminent problems with the engine.
John Schmitt
-- If you have nothing to say, or rather, something extremely stupid and obvious, say it, but in a 'plonking' tone of voice - i.e. roundly, but hollowly and dogmatically. - Stephen Potter
That's my point. SH is the best you can make out of dinosaurs. To get to SJ et al. you need synthetics.
The notion of the SAE worrying about SI is quite bizarre, as it is.
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