Hi!
This is a fun question;-)
40 is awfully heavy oil, I would not be inclined to use it, even if you have
it 'on hand'. You might want to make a gift of it to a friend with a worn
out engine, which is likely the best use for it.
As far as asphaltic based (Texaco, etc.) versus paraffin based
('Pennsylvania') oils go, they are freely interchangeable and mix fine.
Years ago a reaction was possible in unusual circumstances that would
produce a Vaseline like substance in rocker covers etc, but this hasn't been
a consideration for many years.
One tip is you may think about using oil from a different refiner each
change to take advantage of any small differences in additive packages of
the different manufacturers.
Neither type of oil has clear advantages. As a general rule, use whatever
your newest car suggests in all of your vehicles and you should be fine. The
current best API service rating is 'SH' I believe, which is excellent oil.
As far as what grade to use, thats entirely up to you, but I use 5W-30 in
ALL my cars and the limousines we service here which see very hard use and
have excellent results. The main advantage of a 5W-30 over other 'thicker'
grades is it lowers oil temperatures substantially in most engines, and
prolongs the life of seals et al usually. Oils over a 15W-40 such as used in
diesel trucks are not of value in gasoline engines.
The synthetics are excellent oils if you don't mind the expense. One note
also is that additives such as are sold on TV late at night are of
ABSOLUTELY NO VALUE and should be avoided. They won't generally hurt much,
but they aren't going to help any either. I am an avid fan of those
infomercials, and have yet to see one that has any scientific proof to
support its claims. Take your family for Pizza with the money instead.
So, to sum, use a "SH" rated oil of any grade you like, 5W-30 is an
excellent oil for most people. If you typically see extraordinarily severe
service, like mountainous driving, perhaps a '30' might be a good second
choice. I would not suggest 10W-40 or 10W-30 as they offer no additional
protection over a 5W-30. 20W-50 and 15W-40 are satisfactory if the engine
has a very efficient auxiliary oil cooler. The main problems with 'thick'
oils is they drive temperatures up, which largely obviates any advantages
they offer.
Hope this helps!
Brent Covey
>> Have 2 cases Pennzoil 40w HD on hand - should I use it? All I've heard is
>> that it and Quaker State are parafin based and will sludge your engine.
>>
>> Any opinions or comments??
>>
>> Lanier
This is a fun question;-)
40 is awfully heavy oil, I would not be inclined to use it, even if you have
it 'on hand'. You might want to make a gift of it to a friend with a worn
out engine, which is likely the best use for it.
As far as asphaltic based (Texaco, etc.) versus paraffin based
('Pennsylvania') oils go, they are freely interchangeable and mix fine.
Years ago a reaction was possible in unusual circumstances that would
produce a Vaseline like substance in rocker covers etc, but this hasn't been
a consideration for many years.
One tip is you may think about using oil from a different refiner each
change to take advantage of any small differences in additive packages of
the different manufacturers.
Neither type of oil has clear advantages. As a general rule, use whatever
your newest car suggests in all of your vehicles and you should be fine. The
current best API service rating is 'SH' I believe, which is excellent oil.
As far as what grade to use, thats entirely up to you, but I use 5W-30 in
ALL my cars and the limousines we service here which see very hard use and
have excellent results. The main advantage of a 5W-30 over other 'thicker'
grades is it lowers oil temperatures substantially in most engines, and
prolongs the life of seals et al usually. Oils over a 15W-40 such as used in
diesel trucks are not of value in gasoline engines.
The synthetics are excellent oils if you don't mind the expense. One note
also is that additives such as are sold on TV late at night are of
ABSOLUTELY NO VALUE and should be avoided. They won't generally hurt much,
but they aren't going to help any either. I am an avid fan of those
infomercials, and have yet to see one that has any scientific proof to
support its claims. Take your family for Pizza with the money instead.
So, to sum, use a "SH" rated oil of any grade you like, 5W-30 is an
excellent oil for most people. If you typically see extraordinarily severe
service, like mountainous driving, perhaps a '30' might be a good second
choice. I would not suggest 10W-40 or 10W-30 as they offer no additional
protection over a 5W-30. 20W-50 and 15W-40 are satisfactory if the engine
has a very efficient auxiliary oil cooler. The main problems with 'thick'
oils is they drive temperatures up, which largely obviates any advantages
they offer.
Hope this helps!
Brent Covey
>> Have 2 cases Pennzoil 40w HD on hand - should I use it? All I've heard is
>> that it and Quaker State are parafin based and will sludge your engine.
>>
>> Any opinions or comments??
>>
>> Lanier
