New dude here..
 

Hi all. I'm a Mazda technician based in Denton, TX. Learning more about the things every day. I'm no master, but if I can be of help to some of you, I'll be more than happy to oblige. I drive many Mazdas daily lol. However, I own and drive a 98 protege LX 1.5, MTX. I have just over 190K on the car, original motor, and I maintain it religiously. I use Mobil 1, and I still change my oil every 3000 (despite synthetic oil, and despite the owner's manual specifying every 5000). I drive too much to ever be able to go by the "or 3 months" rule. The motor runs like a noise-free champ.

I broke the new guy rule and posted a reply in another topic before posting here lol. So for my second posting, I'd like to offer a random bit of advice if not already followed by the lot of you. If you have an older Mazda (even some as new as 2005) that specifies 10w30 for motor oil (using 5w30 essentially only in below-freezing climates), NEVER use thinner oil unless you have to add some in an emergency and have no other option. You'll notice it if you do by a noisy valve train. If you change your own oil, I would expect that you'd use the right viscosity. But if you have your oil changed at a shop, even if it takes watching them put the oil in, make sure they put in the right stuff. It does make a difference, regardless of what the "I've been doing this for 30 years" mechanic says. 5w20 is only for motors specifying that weight.

Viscosity is not an arbitrary decision. It is determined based on clearances designed into the motor.

RE: New dude here..
 

For some reason this forum keeps adding an extra apostrophe to all of my contractions, such as "I've". Does this happen to everyone?