Using A Different Oil Than Spec

2001 Civic LX - Supposed to use 5W-20 (I think that's what it says on
the cap). I used 10W-40. It's what a mechanic recommended.

Not the 1st time I've used a diff oil than spec. Just wondering if
there can be bad consequences if I use the wrong motor oil?

Also, what exactly do those numbers and letters stand for? I think it
refers to viscosity but I don't remember which number?

Steven

 

What weight does your owner's manual say to use?

I would bet it specifies 5W-30.

Using an oil that is too heavy reduces fuel mileage.

Too light, and engine wear may accelerate.

Googling will turn up much discussion of this. Try, for one:
http://en.wikipedia.org/wiki/Motor_oil

Synthetic oil is a whole other discussion, but probably a
relevant one for you.

 

You can use 5W-30 instead of 5W-20, but don't use 10W-40.
Your mechanic is wrong. The heavier 10-weight will take
slightly longer for the oil pump to pull up.

Not much, really. Perhaps a bit more bearing and cam/lifter wear
from cold.

At the moment, I'm actually considering a 0W-40 synthetic for my car.
After 270,000 miles, its oil consumption (2K/qt) is a bit high for
my tastes.

Google is your friend.
<http://www.google.com/search?hl=en&q=%22motor+oil%22+viscosity+numbers&btnG=Google+Search>
From that search:
http://en.wikipedia.org/wiki/Motor_oil

A quick primer:
The "10W" means it pours like a straight 10-weight would when it's cold.
The "40" means it pours like a straight 40-weight would when hot.

 

TeGGeR® wrote:> You can use 5W-30 instead of 5W-20, but don't use
10W-40.

Thanks for your response Tegger! Very helpful. Unfortunately I don't
know what a straight 10-weight pours like because I have no idea what
"10 weight" means.

Also, I failed to mention in my previous post that I live in the San
Francisco Bay Area where it never gets really cold. That's why my dad
told me it's ok to use the 10W stuff because we never ever get snow.

I'll be watching my mileage to see what I get. The thing that disturbs
me is that when I went to Target they didnt' have the motor oil I
needed for my car. I *could* goto Kragen or some car shop but their
prices are almost always higher than Target. I want to save $$$. If I
didn't care to save money I'd pay a mechanic to change the oil.

I'll look into the links you supplied, thanks again.

Steven

 

Elle wrote:> I would bet it specifies 5W-30.> > Using an oil that is
too heavy reduces fuel mileage.> > Too light, and engine wear may
accelerate.

Thanks for your helpful input Elle! I'll be watching my mileage to see
if my mileage is reduced. I'll also have to look into perhaps using a
synthetic. Although, I'm a bit hesitant because synths cost a lot more
than regular oil, although the trade off is that you don't have to
change as often.

I have a question though, how often is it necessary to change the oil
on newer cars? From my research it looks like there are two schools of
thought. There's the old school where after your car is several years
old you need to change oil every 3,000 miles.

Then there's the new school of thought where auto manufacturers (due to
better equipment on cars nowadays) say that you only need to change the
oil every 7,000 or even 10,000 miles.

Who is right?

Steven

 

Ok, I just checked the oil cap on my car. It says 5W-20. So according
to the links you guys provided I guess I should use the manufacturers
suggestions. Now I have to decide whether to go synthetic or not.

Steven

 

Per your subsequent post, I see I just lost a bet. I googled
and saw some sites saying Honda started specifying 5W-20 (a
lower viscosity oil than 5W-30, of course) in 2001 so that
the company could report hire fuel mileage to the federal
government. See for example
http://www.synthetic-oil-tech.com/d.cgi/1102880/articles/ford5w20.htm

Right. For younger cars, synthetic is definitely more
economical. I count your 2001 as "younger."

Unless the car is /mostly/ driven under any of the severe
conditions listed below, this oil change frequency is
excessive. Severe Conditions (from the American Honda site:
--Trips of less than 5 miles (less than 10 in freezing
weather)
--Extremely hot weather (over 90 degrees F)
--Extensive idling or stop-and-go driving
--Trailer towing, car-top carrier, or mountain driving
--Muddy, dusty, or de-iced roads

(You are in the U.S., aren't you?)

The 3k miles/3 months frequency is a tactic by Honda
dealers, Jiffy Lube, et al. to sell more service. It's a
funny tactic, because Honda itself specifies 10k miles/one
year for your 2001 Civic.

Do you have an owner's manual? It should state the 10k
miles/one year interval above in its maintenance schedule.

I also think the 1996 study Consumer Reports did on this
reinforces how ridiculous it is to change the oil ever 3k
miles. See the article at
http://www.xs11.com/stories/croil96.htm

As for synthetic, this is much discussed here. A few reports
exist of minor oil leaks resulting from switching older cars
with high mileage to synthetic. But the data is really
scarce. For your 2001 Civic, I think you'd be fine switching
to synthetic. But that's only my opinion.

I have a 178k miles 91 Civic LX. I won't switch it to
synthetic, because synthetic is just a tad too much risk for
my budget if a serious oil leak does occur. Also, I change
my own oil and don't mind changing it more often than what
would be required with synthetic. It gets me under the car
inspecting the CV boots etc.

Synthetic vs. conventional oil is much discussed here. You
can search the newsgroup archives for more opinions. Or
google.

 

The first number is the cold viscosity (compared to cold oil) and the
second is the hot viscosity (compared to hot oil). The wider the range,
the more stable the viscosity is. The wide range is often accomplished
by adding polymers that reduce other qualities of the oil. Sometimes
synthetic oil is stable on its own.

The problem with using too thick of an oil is that it pries apart moving
parts, flows slower, and generates more friction heat. 10W-30 is
probably fine in hot climates but I'd drain the 10W-40.

 

Elle wrote:

Thanks for the link, Elle, very interesting to note that it's 10 years
old and the "3,000 mile oil change" ROT is still dominant.

 

"TeGGeR® wrote:> You can use 5W-30 instead of 5W-20, but don't use
10W-40."

I used the 10W-40. Is that bad?

Steven

 

"Kevin McMurtrie wrote:> The problem with using too thick of an oil is
that it pries apart moving > parts, flows slower, and generates more
friction heat. 10W-30 is > probably fine in hot climates but I'd drain
the 10W-40."

You mean I gotta get back under my car and change the oil again?!? Oh
gawd!

Steven

 

Perhaps particularly when the maintenance schedule for
American Honda years from 2001-2005 have been specifyng a
10k mile (and sometimes, but not always one year) interval
for, for one, the specified 5W-20 non-synthetic. At least,
according to the American Honda site's Owner's Link section.

I always thought the hazard of not changing oil regularly,
per the maintenace schedule, was just some accelerated wear.
Finally found something really profound when googling for
friends who recently experienced a thrown rod on their
Isuzu: Thrown rods, for one, do occur when the oil is so
dirty that parts start seizing from lack of proper
lubrication. The net has some interesting "True Confession"
reports from car owners in this vein, like folks that go
over a year without changing the oil.

 

Using an oil that is too heavy may accelerate engine wear too. It can take
too long to get to bearings on cold starts, and it may not permeate porous
bearing material completely.

http://www.geneberg.com/article.php?ArticleID=237

Earle

 

I appreciate the citation and understand (and agree with)
your point, but I am not wild about the line at the link
below that says, "... the heavier the oil, the less it
lubricates." I see the author qualifies this subsequently.
In which case the line I quote above is "just" bad writing,
albeit writing that can mislead.

The extent of lubrication will be a function of temperature,
among other things, as you know. In very hot temperatures, a
heavier oil will lubricate better than a lighter one yada.
Basic stuff.

My viscosity guide chart in my 91 Civic Chilton's manual
shows, generally, higher weight oils to be applicable to
ahigher temperature range than lower weight oils. That also
suggests to me that engine wear is less of a concern with
higher weights and lower temperatures than loss of fuel
economy. That is, engine wear is likely worse with heavier
weights and lower temperatures, but it's not as bad as
engine wear with lighter weights and higher temperatures.

 

Gene Berg drag raced air cooled VW engines in the Southern California heat,
using 20 weight oil. I have to laugh when I see people buying 20W50 at the
local Autozone, to put in the family wagon. When you say "very hot
temperatures" you are talking about a helicopter or an over the road freight
truck, not a Honda Civic, unless it is used for racing.

Earle

 

Probably when they change their undies & socks.

 

wrote in

Engine oils are graded by those "weight" numbers. The number is calculated
from the results of tests that are appiled to engine oils to determine
their thickness, or "viscosity". The smaller the number, the lighter the
oil. The higher the number, the heavier the oil.

A "straight-weight", like the 30-weight that's still common in lawnmowers,
has only one viscosity rating, the "30" part. It gets very thin and watery
at high temperatures.

If you don't want it to get thin and watery when hot, but to stay more like
it was when cold, then you have to play with the oil's structure and
additives to make it stay more-or-less the same within a certain
temperature range. That's where "multigrade" comes in, and the oils are
described using two numbers, such as 10W-30. The first one is always
succeeded by a "W". I think this means Winter.

GEAR oils derive their ratings via similar tests, but those tests are
carried out at lower operating temperatures. Thus their numbers are higher
than engine oils for oils of identical viscosities. 30wt engine oil is
about equivalent in pour-ability to 75wt gear oil.

He's right. Actually, even a 5W is fine. 5W helps ensure the oil starts
circulating slightly faster than it would if it were 10W.


Some synthetics cover an even wider temperature range then regular mineral
oils, such as 0W-40.

 

wrote in

Don't worry about it.