Engine oil grade for 98 Accord

No.

 

Dear experts,

I have a 98 Accord that has 80K on it. Last week
I went an independent deader to get my oil changed.
The technician told me that I should be filling 10-30
or 10-40 oil since my car has a lot of mileage on it.
He said these oil protects older engine better.
The car manual specified to use 5-30 and nothing
else. Is the technician right?

Thanks,
Eugene

 

You should always follow manufacturer's recommendations. However, the
manufacturer may not include all of the information about oil choices
in the owner's manual, so you may want to check with a dealer. The
dealer will have more extensive information about oil choices that, I
bet, include the conditions under which 10W 30 oil might be a better
choice (high temperature, severe service, etc.).

As a general rule, the lower viscosity oils give slightly better fuel
mileage. Honda engines regularly clock over 200K miles with
appropriate care, so 80K may not be a "high mileage" engine. Modern
oils are so good that there is little reason to change based on age of
the engine. Assuming high quality oil. (And, for what ever it's worth,
every mechanic I know uses Castrol GTX in their own car. That's also
what my Honda dealer uses at oil changes.))

On the other hand, as far as I know, there would be no problem
substituting 10W 30 for 5W 30, especially if the ambient air
temperature is high enough, as for example right now in Austin, Texas,
where we are flirting with 100 degree days.

It is my understanding that 10W 40 oils should not be used under any
circumstances. To get that large viscosity range, oil manufacturers
have to add "viscosity improvers." These are various polymers that
stay balled up at low temperature but unwind and tangle together at
high temperature. When they tangle together, that raises the viscosity
of the oil. If that sounds like it might be bad for your engine, you
should know that experts also think it might be bad.

Anyway, that's what I was told.

Elliot Richmond
Freelance Science Writer and Editor

 

Who do you believe? The engineer from Honda or a simple
technician? To have credibility, the tech better have science
facts to support his speculation. No solid facts neither
based upon science nor supported by numbers? Then he is
probably promoting junk science.

This is not just how one selects motor oil. Some are so
foolish as to believe the junk science reasoning from
mouthwash manufacturer such as Listerene and Scope. If their
reasoning was correct, then Vodka is a better mouthwash and is
superior to a tooth brush with fluoride toothpaste. Where is
the science that says mouthwash is so effective? Same
mythological reasoning.

Consult Honda. If the tech says otherwise then hold his
feet to the fire. Either he will provide those facts (an
honest man) or he will get emotional (symptoms of a myth
purveyor).

 

I don't want to be too caustic; rather, I want to present another point of view
re going to the dealer.

The dealer's time is money. Given what I think is a high turnover of technicians
and service managers in the business, and how busy dealer service departments
are, I wouldn't count on many dealers fielding this question with integrity or
expertise. They might have a correct answer, but from too much bad work by
dealers, I wouldn't rely on them as being "expert."

Now maybe Elliot has a dealer whom he really trusts. But I've worked with a few
dealers and found it's a roll of the dice as to their people's competence.

Last time I called the dealer for some basic parts information, as an aside to
my query some yahoo there told me the crankshaft bolt was left-hand threaded.
Wrong. Thank god I knew better and just ignored this gross mistake.

In order, go to
1. the owner's manual
2. service manuals such as Helm or Chilton's
3. the newsgroups
4. the Google search engine
5. other resources suggested by the newsgroup
6. the dealer

Weigh all the information and come to a decision

I don't buy the technician's cousel at all, based on reading over the years.

Caroline
1991 Honda Civic LX, 155k miles, Pennzoil 5W-30 always, 40+ mpg 3/4 of the year.

 

Hmm. I googled: {oil viscosity engine older car} Some sites do say that, at some
point in an "older" car's life, switching to a higher viscosity oil,
particularly in the summer, might be prudent. Criteria are as one would expect:
Higher oil consumption than early in life, for example.

 

Yeah, maybe.

But the tech said 10-30 instead of 5-30.....so he's claiming the car needs
thicker oil when *cold*, and the same viscosity when hot.

And that's a little....odd.

 

?

I don't understand your inference that the tech is saying something about the
engine's needs when it's cold.

Aside: Like every auto oil web site I've seen, in this thread I'm taking
"thicker" to mean "more viscous." "Thicker" does not refer to density in this
context. Water is more dense but less viscous than 5W-30. Yada yada big deal, I
know.

If the tech had said this, then I would agree.

A car generally needs lower viscosity oil when cold, and higher when hot.

But barring any specific car age issues, I understand 5W-30 is fine for a very
wide temperature range for your typical car built at least after 1990 and maybe
going back even further. The oil experts can elaborate as they wish...

 

Your technician is wrong. This was a standard practice many years ago
when engines were constructed to loose clearances.

The engine has small passages to distribute oil to where lubrication is
required. These oil passages have been sized to distribute oil flow
approriately with the correct weight oil. If you use a thicker oil, the
oil will flow through the smaller passages slower, thus providing less
or no protection. This will especially be a problem on cold start.

Use the manufacturers recommended oil weight. A synthetic such as mobil
1 or amsoil of the correct weight will extend your motor's life.

Also, change the oil (and filter) at 3000 miles. Extended oil changes
are poor economy because engines are much more expensive than oil.

 

Um, the reason that Honda and other manufactures recommend thinner oils
is for improved gas economy period.

ANY engine that has more than 100K requires a higher viscosity rating.

And, if you're gonna change oil every 3K, it's a waste of money if
you're using a quality oil such as Castrol or Valvoline when 5K is fine
and even 7.5 K is ok.

Now, if you use crappy stuff like Penzoil, Quaker State and most store
brand stuff, you better make it 2.5K on the changes.

A note on synthetics... My opinion that it is a waste of money for
engine lubrication because of suspended particles typical of internal
combustion engines. OTOH, synthetics in transmissions, differentials,
power steering is truly a smart move.

JT

(Who has been fiddlin' with infernal comustion engines for nearly fifty years...)

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