Gas Mileage problem -Solved!

Hi All,

Remember when I purchased my newer 2002 Grand Caravan? And how I
simply was NOT satisfied with the mileage???

Well I am in to solving problems, and have a warranty, so all kinds of
things have been done - to no avail! It runs real smooth, just not
nearly the mileage I used to get with my 1994 GC with the same
displacement engine (3.3 litre).

I am also one who believes in proper maintenance, so being as I was at
about 101,000 km, and I had NO faith that the previous owner did ANY
preventive maintenance... off to my favourite Trans Shop for the
installation of a booster cooler, and a complete fluid change with new
filter.

Fair enough, service when as planned, no nasty little surprizes at the
trans shop, no codes, all is well.

And if I thought it shifted good before, it is AWESOME now!

All good. Then....

I have the overhead console - and I have it set to display my mileage
in real time. In driving around over the last couple of weeks, I
happened to glance up. My MPG is UP! by about 4 to 6 MPG! This puts
the new van EXACTLY in line with my 1994!

I never noticed this with the 1994 because the trans DIED about 2
weeks after I purchased it! So when it was rebuilt, it had new fluid
in it.

I will keep detailed mileage logs for a while to confirm, but the
readings persist, and are consistant - and the ONLY recent change was
the tranmission fluid!

As if doing this PM as a matter of course was not enough, and as a
matter of saving your trans, now you have ONE MORE reason to do it! At
todays gas prices, that extra MPG will quickly pay for the cost of the
service!

Just thought you would like to know!

 

The best mileage that I have ever seen with my 1993 GV with a 3.3 is
about 23 MPG highway. I don't know how that compares with what you are
getting.

-Kirk M

 

With my 1994 GC I was getting about 25 Miles per US Gallon on the
highway - fully loaded with A/C ON. With light load and A/C off, 27
Miules per US Gallon was not unheard of (roads around here fairly flat
- no "mountain" driving).

City driving used to be 19 to 22 Miles per US gallon.

So far, in my 2002 GC, I am seeing the meter jump between 27 and 33
Miles per US Gallon on the minor highways around town (no traffic
lights).

I will keep an eye on this the next time I go for a major trip.

 

I suggest collecting data between fills for a more accurate MPG reading.
I keep a record of all my fills and ODO, so I know exactly my MPG.

 

Yes, this is what I usually do as well. Fill to full, and record the
kms on the ODO. That is the REAL measure, although there is some
subjectivity to what is "full", but since I pump it the variation
should be reduced.

I don't drive too much these days, so I will post back when I have
more data.

 

I seriously doubt a fluid change made any difference. Chrysler does not
recommend changing out the +4 fluid; ever! (Not that I follow that
recommendation myself). Only if the vehicle was stuck in the wrong higher
gear would the transmission make much difference in fuel consumption. Now,
if Chrysler would give us direct fuel injection we might see a real
improvement in both performance and fuel economy.

Richard.

 

While I'm also skeptical that the fluid change would make much gas
mileage difference (maybe it was so low the transmission was in
limp-home mode?), my 2000 Intrepid FSM recommends changing the
transmission fluid every 100K miles in normal service, every 48K miles
in severe service conditions.

 

Keeping in mind that there is a difference between winter and summer fuel.
Could this be the difference in gas mileage?

Glenn

 

I don't think so. We purchased the Van last summer (late July). The
mileage has been consistantly low since the day we purchased it. If
seasonal gas variations were the reason, then I would have expected
that the mileage in the summer was good, and then it should have gone
down in the winter.

Besides, we try not to drive too much with todays prices. I had topped
up the tank just a day or so before going to the shop, and the mileage
was still low by caluculation, and low by reading on the overhead
console.

Now the overhead console reads better MPG. So I am waiting for the
next fill to see if the calculated value bears out the console
readings. Who knows, maybe my overhead console is in the fritz! But
that is also covered by my extended warranty, so I am NOT worried.

So far, the only change - or should I say the only change I am aware
of, was the transmission fluid. Whoddathunkit?