Why would you do a silly thing like that?  Synthetic is more improtant if
you have longer oil change intervals.  I have been using them for over 20
years in my bikes and autos.  Using conventional oil old technology like the
dinosaurs it came from.  Would you trade in your color TV for a black and
white one?
Coasty

I have an '05 Chrysler 300C that I bought used with 24,000 miles on it and
the previous owner used only synthetic oil since the car was new.  I have 3
cars and only put on 4000 miles or so a year on this one.  I  change the oil
only once a year and with the low miles driven I wonder if it makes any
sense putting in the synthetic oil.

Any harm switching  to regular 5W-20 oil?

news:8RwSf.33$IW6.12@fe12.lga...

the previous owner used only synthetic oil since the car was >new.  I have 3
cars and only put on 4000 miles or so a year on this one.  I  change the oil
only once a year and with the low miles driven I >wonder if it makes any
sense putting in the synthetic oil.

No, don't do it!

With only 4000 miles a year you are probably putting that mileage on with a
lot of very short trips
which are not giving the oil a chance to heat up to full operating temps and
stay at those temps for
a good long time.  That is required to boil off all the volatiles like
gasoline and water that are blown
by the rings and get into the oil.  This is extremely hard on the oil and
you are much better off
using synthetic.

Ted

Hi...

I have absolutely no qualification to answer this, but nevertheless
offer an alternative for you to consider, if I may?

I'm quickly turning into a dinosaur myself, so aside from a few
100 mile trips to the lake in the summer, mine spends the long,
cold Winnipeg winter making 5 mile round trips to the grocery and
bank and Doctor once every week or two.  Heck, a tank of gas
in the fall is still there come spring :)

What I decided to do is change the oil once every 3 or 4 months
despite their being almost no miles on it, but use one of the
lower end mineral oils.  This way I get to drain any gunk in the
oil, and the cost isn't much if any greater than changing less often
with more expensive synthetics.

Just food for thought...

Ken

I don't know why you do that. Oil changes are almost 2 times longer between with the synthetic. I started using it on my dakota at 8,000 miles and have now over 85,000 on it and it don't drip one bit, runs cooler, easier to start in the winter (don't turn into syrup when really cold). And I stretched the changes to 7,500 miles.  Go mobil and a top grade filter you can't go wrong.
 I have an '05 Chrysler 300C that I bought used with 24,000 miles on it and the previous owner used only synthetic oil since the car was new.  I have 3 cars and only put on 4000 miles or so a year on this one.  I  change the oil only once a year and with the low miles driven I wonder if it makes any sense putting in the synthetic oil.

 Any harm switching  to regular 5W-20 oil?

No harm.  Might still want to consider changing the oil more often than
once a year though.  Most maintenance charts list a time limit as well
as a mileage limit.  Often the time limit is more important.

Matt

Absolutely no harm in switching back and forth between synthetic and
regular "dino" oil.  However your logic might be backwards. And there
are a couple of ways of looking at it.

1) *Because* your looking at a once per year oil change interval, you
should be looking at keeping the highest quality oil/filter in the
engine, not looking to lower it.  You have one of the best reasons to
use expensive oil/filter.

2)As someone pointed out, the concern with low annual mileage like yours
is that it means that there are probably a lot of short trips.  This
usually leads to moisture and fuel contamination of oil, which degrades
the oil quality faster than someone that puts 4000 highway miles on over
a 2 or 3 month period.  Moisture/fuel contamination of oil often leads
to low temperature sludge formation in the engine. Viewed this way, you
could justify changing the oil/filter every 3 months. And you could
further justify using a much less expensive (but good quality) non-synth
on that basis.

3) If you read your owners manual carefully, it probably lists your type
of driving as "Severe Service" (ie most trips are less than 10 miles or
so),  and that will call for 3 month oil change intervals, regardless of
how low the mileage is at the end of 3 months.  You should not ignore this.

The above options are a bid at odds with each other.  The real answer
for you will be to get an engine oil analysis done, and let the analysis
guide you.  In your case I would probably get an analysis done 3 months
into an oil change and see what the numbers look like.  It they're OK,
go another 3 or 4 months beyond that and have it done again.  You'll
only have to do this a couple of times to find out what the real, safe
oil change interval for your engine and driving habits will be.

You can get further advise and help with interpreting the analysis at
this excellent site :

http://www.bobistheoilguy.com/

I'm not sure about the 5W-20 oil for the 300C engine (3.5 L V6 ??).
5W-20 is being used more a more in modern engines; Ford and others have
been using it as a factory fill in a number of vehicles for several
years now. I would call the toll free number in the owner's manual and
get an opinion from Chrysler about it. You should see a slight
improvement in gas mileage with it. But at only 4K miles per year, does
it really matter.

Good luck...Phil

Thanks to all for the information.  I will stick with synthetic.
 I have an '05 Chrysler 300C that I bought used with 24,000 miles on it and the previous owner used only synthetic oil since the car was new.  I have 3 cars and only put on 4000 miles or so a year on this one.  I  change the oil only once a year and with the low miles driven I wonder if it makes any sense putting in the synthetic oil.

 Any harm switching  to regular 5W-20 oil?

If that 300C was mine, I'd stick w/ synthetic and I'd   also use the
best oil & air filters in car care business. Cars with synthetic from
as early as you say, will hardly use oil if everything is in top shape.
Cars that have been on petroelum, run a risk of using oil because of
wear. Others here have said that short trips are "severe" and that's
someting most people forget.

If you ONLY change the oil once per year, then why on earth NOT spend
the extra for synthetic?!?!  Synthetic might make a noticeable cost
difference if you were changing the oil 5 times a year... but then I'd
argue that you're piling on so many miles that you'd still be better off
with synthetic and extending your change intervals out.

But no, there would be no real "harm" in switching. Just not much logic.