MX-3.com

Hello again!

Posting this for a friend (who now owns my MX-3), in the UK climate (generally not so warm) what's the skinny on using 5w-40 oil (instead of 5w-30)?

My guess is that since it's thicker, when the engine gets to super-nova temperatures (as it does) the oil will be able to handle things better, and performance wont drop off so much (at the moment when engine is hot there's slightly less punch)

It's Mobil1 by the way.

Cheers,
Dave

Dave-UK-MX3-V6-SE wrote:(at the moment when engine is hot there's slightly less punch)

This has absolutely nothing to do with the oil viscosity.

Thanks!

(I know nothing about oil, didn't I mention that?)

I presumed that the more viscose the oil is, the higher tolerance it has for excessive temperatures.

Since you seem to know your stuff however, could you answer my query?

Gracias,
Dave

lakersfan1 wrote:

Dave-UK-MX3-V6-SE wrote:(at the moment when engine is hot there's slightly less punch)

This has absolutely nothing to do with the oil viscosity.

Agreed. Suspect the performance drop when the engine is hot has more to do with warmer ambient air being drawn by the intake. Warmer air is less dense than the cooler air drawn thru the intake when the engine is cold = "slightly less punch."

OK guys I get the point!

To those who post from now on - I'd really appreciate it if you could answer my question rather than pick up ONLY on the flaws of it...

Thanks...

A synthetic 30 weight oil already handles the heat as well as a regular 40 weight oil does. A 5W40 will work just fine in our cars. So will a 0W50, 5w50, 0W30, 5W30, 10W30, 5W40, 10W40. There may be slight viscosity differences between any two at a given temperature, but they all cover the minimum requirement of 10W30 that the owner's manual requests.

i don't see why you wouldn't just go with a 5w-30 instead of trying all these fancy oils for cold climate, and 10w-30 in the warmer times. Mazda said it needed those types of oil, so why not stay with that. But Mazda also thought the 1.8L v6 would be a good engine... so they aren't always right!

slowmx3 wrote:But Mazda also thought the 1.8L v6 would be a good engine... so they aren't always right!

It was in Europe where cars are taxed based on thier engine size. It's in every manufacturer's interest to have a sub-2.0L and sub-1.8L engine options. I think they stayed away from the 2.5L in the MX3 in the U.S. to keep from taking away from MX6 sales.

The 1.8L is a bad-a-- engine. smaller than anything else ever made at the time and lasted for a long time IMO. I've never seen a bad K8. I have seen them with poor piston rings, but that is a small price to pay for such a powerful tiny engine.
You say "what!! powerfull, since when was 130HP powerful???" well compared to any other 1.8L four banger of the day it had more power. Revs quick, decent torque from a small motor, good milage, high rev limit. It was a tech marvel at the time.

very smooth engine too

"well compared to any other 1.8L four banger of the day it had more power" that is arguement that doesn't need to be brought up. And i was kidding, but i thought my K8 sucked. But thats just mean, lets stay on topic.. My bad...