My Mercruiser manual says to use 5-40.

What the hell is that? so 10-40 isn't good enough? Real reason is to
cause F.U.D. to discourage boat owners from doing work themselves.

no, 5w-40 lubes better upon ambient temp engine startup that 10w-40 and much
better than 30w or 40w does.

however, the difference between 5w-40 and 10w-40 isn't all that great. In
past, 5w-40 didn't hold up as well under long service, and so was seldom sold.

"JAXAshby" wrote in message
...
My Mercruiser manual says to use 5-40.

What the hell is that? so 10-40 isn't good enough? Real reason is to
cause F.U.D. to discourage boat owners from doing work themselves.

no, 5w-40 lubes better upon ambient temp engine startup that 10w-40 and
much
better than 30w or 40w does.

however, the difference between 5w-40 and 10w-40 isn't all that great. In
past, 5w-40 didn't hold up as well under long service, and so was seldom
sold.

Thanks all. With all that, I don't see any reason that a 20w-40 or 20w-50
would not be a preferable choice to plain old SAE 20, 30, or 40 which are
all recommended in my 1987 manual.
-Dan O.
Minneapolis

With all that, I don't see any reason that a 20w-40 or 20w-50
would not be a preferable choice to plain old SAE 20, 30, or 40 which are
all recommended in my 1987 manual.

operating weigh above recommendations can harm seals. thus using 20w-40 in
place of 20w doesn't do any good for lubing upon engine startup and can do some
harm when the engine is warm.

some people are under the mistaken impression that multi grade oils "thicken
up" as they warm up. they don't. they just thin out less as they warm up.

(JAXAshby) wrote in message ...
With all that, I don't see any reason that a 20w-40 or 20w-50
would not be a preferable choice to plain old SAE 20, 30, or 40 which are
all recommended in my 1987 manual.

operating weigh above recommendations can harm seals. thus using 20w-40 in
place of 20w doesn't do any good for lubing upon engine startup and can do some
harm when the engine is warm.

some people are under the mistaken impression that multi grade oils "thicken
up" as they warm up. they don't. they just thin out less as they warm up.

a 30w oil will keep its viscosity over a much broader temp range then
a multi weight oil. this is the reason for this recommendation. they
are also better for heavy load conditions, because once again load
creates heat and a 30 w oil will stick around better.

just to clarify jax a 5w-40 oil is 40 at rest/cold therefore will take
more time to pump anywhere being theoretically 25% thicker then a 30w
oil.
perhaps leave the vitriolic attacks at home for people that are just
trying to help. do some reading on oil viscosities is my
recommendation to you.

manufacturers dont make recommendations for no reason, follow them and
you will never have any trouble.
if you are having trouble finding a 30w oil any volvo dealer will sell
it as a lot of volvo equipment uses that grade.

ben, that is utter bull****.

a 30w oil will keep its viscosity over a much broader temp range then
a multi weight oil.

30w oil viscosity ***changes*** over the entire temp range.

ben, that is utter bull****.

just to clarify jax a 5w-40 oil is 40 at rest/cold therefore will take
more time to pump anywhere being theoretically 25% thicker then a 30w
oil.

5w-40 is ***5w*** at cold temp.

kriste on a crutch, ben, 14 year old boys know this.

bennie, I own a mid-80's Fiero and right on the oil fill cap if embossed the
directions to use 5w-30 oil. That means for 20 years at least the manufacturer
GM has recommended multi-weight oil.

in fact, GM has recommended multi longer than that, since the 1970's

go ahead. tell us it was a GM plot to sell us more cars.

manufacturers dont make recommendations for no reason, follow them and
you will never have any trouble.
if you are having trouble finding a 30w oil any volvo dealer will sell
it as a lot of volvo equipment uses that grade.

JAXAshby wrote:
bennie, I own a mid-80's Fiero and right on the oil fill cap if embossed the
directions to use 5w-30 oil. That means for 20 years at least the manufacturer
GM has recommended multi-weight oil.

in fact, GM has recommended multi longer than that, since the 1970's

go ahead. tell us it was a GM plot to sell us more cars.

Larry doesn't post here anymore.


--
We today have a president of the United States who looks like he is the
son of Howdy Doody or Alfred E. Newman, who isn't smarter than either of
them, who is arrogant about his ignorance, who is reckless and
incompetent, and whose backers are turning the United States into a pariah.

What, me worry?

Subject: Mulitgrade Oil
From: (JAXAshby)

bennie, I own a mid-80's Fiero

OTFLMAO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!

Capt. Bill

(JAXAshby) wrote in message ...
With all that, I don't see any reason that a 20w-40 or 20w-50
would not be a preferable choice to plain old SAE 20, 30, or 40 which are
all recommended in my 1987 manual.

operating weigh above recommendations can harm seals. thus using 20w-40 in
place of 20w doesn't do any good for lubing upon engine startup and can do some
harm when the engine is warm.

some people are under the mistaken impression that multi grade oils "thicken
up" as they warm up. they don't. they just thin out less as they warm up.

here is an explanation as to why not to use a multigrade oil unless
specified by the manufacturer
hope this helps