I have a new 09 Mazda5 ~ would you recommend syn oil or dino, also is this a simple dyi job or a bit more difficult? Thank You!

 

Conventional or synthetic? As with most things, it depends.

Are you inclined to change your oil every 3,000 miles? If so, then using synthetic oil would be a complete waste of money.

Are you inclined to change your oil per Mazda's recommended OCI of 7,500 miles? If so, synthetic might be a good idea.

Once your warranty is over, are you inclined to push your OCI to 10,000 miles or more (as I am inclined to do)? If so, then you should probably opt for synthetic (as I absolutely will do).

As for changing your own oil...
Yes, it's more difficult than changing the oil in say a Jeep or other high riding vehicle, that said, once you've done it for the first time, it isn't all that hard to do.

 

I tend to change mine every 3000 miles and I am running Motorcraft Synthetic Blend 5w/20 in my Mazda 3.
To change the oil yourself you will need to get an oil filter wrench that fits the Mazda cartridge oil filter (not a spin on Filter).
I bought 5 filters from an online Mazda dealer and they gave you the wrench for free.
Also if it is anything like the 3 you will have a lower engine cover, on the 3 you need to remove 7 10mm bolts and 2 push in clips to get to the filter. Like I said, this is on the 3 and I have not seen under a 5 so it may be different.

 

I find that for the time and effort it takes, you really don't save that much money doing it yourself. Sure its a bit cheaper, but really not by all that much. Where I live the oil and filter, if I went out to buy it at walmart, will cost close to $30, and taxes included, to have the dealer do the change, its just under $40, so for around $10 I save my self the mess, the old oil disposal, and the time. For me, its worth having them do it.

 

With what I run with the Motorcraft oil and the Motorcraft Filter is under $17, So to me the savings of $33 (oil change at my Mazda dealer is $49.95 and the local Oil Change place does not have the correct filter wrench for the 2.3 Liter) and the piece of mind knowing it is done right is well worth it.