Synthetic oil

I just changed the oil in my car with synthetic oil. I have always been a stickler about changing the oil every 3,000 miles or three months but things have changed. First I have a new car and I retired. I bought the car in 2009, it was a 2008 model, so the oil was a year or more old when I bought it. I changed it immediately and then again a few months ago when the mileage reached 5,000 miles.

Here is the question, I drive this car very little, less that 2,300 miles in the five months since my last oil change. I live in a temperate climate (Virginia) so there are no seasonal demands on the oil. This last change I deciced to use synthetic oil, I know it is supposed to last longer mileage wise but should I be concerned that the viscosity will break down if I don’t change it for 8, 9 or even 10 months?

Is this car under warranty?
If so, do you want to keep the warranty valid?
If so, then you must change the oil at least as often (miles or time, whichever is first) as the book says to do.

Don’t care about the warranty, then change it once or twice a year.

Lets say I don’t care about the warranty as far as the oil changes go. Will the viscosity of the synthetic oil be consistant for a few months or more? The guy that changed it this time said that if I came back with less that 5,000 miles between changes, regardless of the time, I was wasting my money. Was he correct?

I would agree with your oil change guy. While there are some benefits to synthetic, you would do just as well on conventional. That said, you can also go a year or so between oil changes (based on my personal experiences with out of warranty vehicles). One caveat might be if you are doing a lot of “severe” service, short trip stop and go driving. Then you are probably best with changing conventional every 3-4K miles or so.

from the owner’s manual:

Scheduled Maintenance (USA, Canada, and Puerto Rico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following conditions
If any do apply, follow Schedule 2 (Canada and Puerto Rico residents follow Schedule 2).
l Repeated short-distance driving
l Driving in dusty conditions
l Driving with extended use of brakes
l Driving in areas where salt or other corrosive materials are being used
l Driving on rough or muddy roads
l Extended periods of idling or low-speed operation
l Driving for long periods in cold temperatures or extremely humid climates

Schedule 1: 6 months or 7,500 miles
Schedule 2: 4 months or 5,000 miles

Do it at least as often as recommended. I’ll bet you are a schedule 1 driver, but only you know for sure. I commute in the DC area and I am definitely a schedule 1 driver. That’s got to be the most stressful driving for your car in VA.

Nope, not a schedule 1 driver. I used to live in NOVA and know the conditions and that is why my 1994 Miata was parked in a garage and only driven on the weekends while I lived there (METRO and carpools were wonderful). Now I live in the Roanoke area and most of the driving is kinda midrange. As I said, I am retired so if things are really bad (snow, ice and the salt they put down for those conditions) I stay home. I only had 2,300 miles on the car but 5 months before my most recent oil change (when I decided to try synthetic. My only question is if there should any problem with the viscosity of synthetic oil (or conventional oil for that matter) breaking down with low, easy type of mileage over a period of months? I am talking about something like 4,000 miles within 7 months. If not, why the 3,000 miles “OR 3 MONTHS” recommendation on regular oil?

The 3K miles/3 months recommendation is your mechanic’s or oil changers. Note that both Mazda Schedules are longer than 3 months/3K miles. I would put my faith in Mazda’s recommendations.