Before you jump on the synthetic band wagon, look at the driving
conditions you are in.  If the filter is blocked after 5k that means
that the oil is dirty after 5k.  Whether you are running syn or reg, if
it's dirty it needs to be changed.  Even if the molecular structure of
syn oil doesn't start to break down until after 10k if may be dirty
long before that.

Thanks for the input Tony, I think based on what I have read and the
response here, we are going over to sythentic. I have never cut one of these
filters open after it was used to see whats in there but will also do that
just for future reference.

Bill

Using one of the better filters, I wouldn't bother changing the filter
at 5000 if you change the oil at 10K. Filters like Mopar, AC, Motorcraft
are usually supplied by various makers after a bidding process. In the
filter tests AC initially tested fabulous and then went to hell. They
cut them open and found 2 obviously different manufacturers. Mobil 1 and
K & N are built to spec. and their higher quality is easily seen before
you even cut them open. You can get them online for less, though Mobil 1
is so popular even Walmarts, etc, sometimes carry them.

Thanks for the reply Tony

One other question comes to mind regarding the oil filters. With the added
mileage that the synthetic oil can be run between changes, do you change the
filter (for example) at 10,000 miles when you change the oil or would you
change the filter at 5,000 miles and then change the oil and filter at the
10,000 mile mark. On all the write ups I have been reading on the subject no
one seems to mention this aspect. On big diesel engines you have a
differential pressure gauge/switch across the filter so you know when the
filter needs changing but for car/truck engines there seems to be no real
consensus. With regular oil I change the filter every time I change the oil
but this synthetic stuff is a different beast.

Bill

Use whatever oil viscosity is recommended for your conditions listed in
the manual. And avoid advertising bs from the mfg or owners. IE if the
local Lubimart has Pennzoil syn half price, buy that. Putting purple or
red dye in an oil may make it way cool, but you have to pay to be cool.

Filters have been tested and the top ratings go to Mobil 1, K&N and Wix.
NAPA gold is usually a Wix filter. Absolute garbage in a league all
their own is Fram.

I was thinking of changing my oil over to the new synthetic stuff. I drive
an 03 grand caravan with a 3.3ltr engine. The first question is 1) al lot of
people are saying to go to 15w40 rather than the 5w30 that is presently
recommended when using regulare oil. Has anyone been using 15w40 synthetic
oil and had any problems with it. 2) The reason I would like to go to the
synthetic oil would be to increase the mileage between changes but I have
been doing some reading on the net and some articles suggest that the usual
oil filters you buy in Canadian Tire or Wal-mart (fram etc) only actually
filter oil for about 4000km and after that I guess the oil just passes right
through them unfiltered. Are their recommended oil filters out there that
one should use when using synthetic oil.  I don't see the point of changing
over to the better oil if the filter is not going to be the weak link?

Bill