not for post 1980 vehicles ?

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Jul 21, 2004
hi there

why would a gallon of dino 20w50 have a sticker saying 'should not be used on a post 1980 vehicle'.

is this because

a) it's not up to the job (however short the oil change)
b) they want you to buy the synth's and semi-synth's on the next shelf.
c) none of the above.

i bought this to top up my 1989 mercedes 300te with 185k and my daewoo matiz with 55k. the merc does a couple of 300mile journies each month and the daewoo is a city car.


My guess is a) not up to the job. Look on the label information to see if there is an API specification. SL is the current rating and the oil you bought is probably an SE, an obsolete rating, which is good for engines made through 1979. If the oil you bought is an SE rated oil, then you may not wish to use it.

Tell us all more about the details on the label and someone can probably give you a better answer.

Good luck.
hi there

there are no api ratings or declarations of any sort,

but it declares that added ingredients are:

1)calcium sulphonate - a corrosion inhibitor
2)calcium phenate - a petroleum detergent
3)ethylenediamine - ashless dispersant to reduce sludge and varnish.

it all sounds good to me.


My guess is it should say "post 1974".
Meaning it could be harmful to catalytic converters. But I take that back because I just realized your in England. When were cats. mandated over there?

Other than that, I can't see it not being up to the task. I mean on the macro scale, engines haven't changed that much.

Good luck
Guys he is in GB. I dont believe many cars in Europe went to a catalytic converter until around 1980. I suspect it may be a high phosphorus oil or have some other additive that prevents meeting ACEA standards for newer engines.

I believe both the vehicles in question have petrol (gas) engines?

I cant say whether its a good oil or not but if your vehicles have a catalytic converter and consume oil it could shorten the life of that component.

we got catalytic convertors fitted 2 all new vehicles in '92 in the uk.
Don't know why it would say that on the oil though, 20w50 was still used in some car's in the 80's, though their engine/design was probably from much earlier.
What brand is it? I would guess it was one of those specialist oils made for classic cars.
hi there

did they design the engines to fit the oil criteria ?

surely not


If I remember correctly, I think 1980 was the year that the "SF" rating on oils became effective, and the recommended rating for most vehicles....This implies that the oil you have is rated "SE".....
My guess would simply be that it is just generally considered to thick an oil for newer engines in a colder climate.

Generally most 20W50 oils are now considered "older" car oils, and usage recommendations come down to climate conditions, generally just about anything after 1980 comes with a general "world" oil recommendation of around the 10W30-15W40 mark, and unless you never see temps under like 0-5celcus it's not recommended to use anything above that rating.

I seriously doubt it has anything to do with the oil quality, just the oil company covering it's *** in terms of handbook and general manufacturer recommendation ratings.
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