Switched to 5W-30 from 0W-20

yrwei52 said:
The reason why I plan to switch from my current Mazda 0W-20 moly oil to Castrol Edge 5W-30 oil is twofold. Firstly I prefer Mazda worldwide approved 5W-30 viscosity than 0W-20 for less valve noise being reported by many 2.5L NA owners here. Secondly the price has gone up significantly on Mazda parts nowadays, and its 0W-20 moly oil now is $11.15 per quart MSRP comparing to $7 per quart in old days when I bought a couple of cases. I simply feel it’s now over-priced even with high moly content in oil. Remember Mazda’s 5W-30 factory fill in 2.5T has minimum moly content, as Mazda doesn’t offer moly oil on 5W-30 viscosity.
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-- I appreciate your conclusions and believe what you say is true - Im riding out my first oil change in which I used 0w-20 Mazda OE w/moly -- I am going to switch to 5W-30 viscosity on the next oil change - quasi post winter- I just wanted to know if you liked the Castrol Edge over the Mazda OE 5w-30- The dealer wants $16/ a quart for 5w-30 --so If Im doing it --its going to be Castrol or Mobil -1 - Castrol is about $30 for 5 qts same with Mobil-1
thanks again
 
Changed my oil today. Stayed with 5W30 synthetic. Went to a quicky lube place with my own OEM filter (from Amazon). It was a Thailand made filter, btw. Not one of these MV things.
Car is very happy running on 5W30.
 
GTXT23 said:
-- I appreciate your conclusions and believe what you say is true - Im riding out my first oil change in which I used 0w-20 Mazda OE w/moly -- I am going to switch to 5W-30 viscosity on the next oil change - quasi post winter- I just wanted to know if you liked the Castrol Edge over the Mazda OE 5w-30- The dealer wants $16/ a quart for 5w-30 --so If Im doing it --its going to be Castrol or Mobil -1 - Castrol is about $30 for 5 qts same with Mobil-1
thanks again
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Mazda OEM 5W-30 oil is NOT the same as Mazda Moly 0W-20 full synthetic oil! Some even believe Mazda OEM 5W-30 oil isn’t a full-synthetic oil as the package doesn’t say it’s! I’ve seen the report that Mazda OEM 5W-30 oil actually is the re-labeled Castrol GTX 5W-30 oil which isn’t synthetic oil.
 
yrwei52 said:
Mazda OEM 5W-30 oil is NOT the same as Mazda Moly 0W-20 full synthetic oil! Some even believe Mazda OEM 5W-30 oil isn’t a full-synthetic oil as the package doesn’t say it’s! I’ve seen the report that Mazda OEM 5W-30 oil actually is the re-labeled Castrol GTX 5W-30 oil which isn’t synthetic oil.
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Yikes - Mobil-1 it is- I suppose the belief that all multi-viscosity oils are by nature synthetic...is false ?
It begs the question, how then does a "dino" oil become multi-visc ...and NOT be synthetic ?
 
ruthrj said:
Castrol Edge is the synthetic, that or Mobil 1 synthetic will be just fine : ) Castrol GTX is the conventional oil Yrwei was referring to.
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I see -- well thanks - I was going to recheck before purchase -- I thought he said Edge in another thread on oil --wasnt sure
 
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GTXT23 said:
I see -- well thanks - I was going to recheck before purchase -- I thought he said Edge in another thread on oil --wasnt sure
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But ....Castrol 5-w30 GTX is full synthetic and GF-6 ? So is Edge and Edge extended life - ? I suppose they all work fine
 
GTXT23 said:
But ....Castrol 5-w30 GTX is full synthetic and GF-6 ? So is Edge and Edge extended life - ? I suppose they all work fine
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My bad. We’re talking two different flavors of GTX. I didn’t realize they made a full synthetic (not available on my local Walmart). All I saw were the white bottles, synthetic/conv blend.
IMG_5888.jpeg
 
GTXT23 said:
But ....Castrol 5-w30 GTX is full synthetic and GF-6 ? So is Edge and Edge extended life - ? I suppose they all work fine
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I’ve been using Castrol oil since 1980’s. At the time Castrol mainly was selling Castrol GTX of course that was conventional oil. In 1990s Castrol came out with Castrol Syntec full synthetic oil where the “Syntec” name used only in US market. In 2000’s Castrol Edge series full synthetic oil came out but we still can see Castrol Syntec at certain places. In 2010’s I also noticed Castrol GTX has changed to “blend”, and now we also see Castrol GTX full synthetic oil.

I still have a couple of boxes of Castrol GTX 5W-30 conventional oil in white quart bottles. And that’s the oil my 1998 Honda CR-V EX AWD with 189K miles has been using since new.
 
GTXT23 said:
Yikes - Mobil-1 it is- I suppose the belief that all multi-viscosity oils are by nature synthetic...is false ?
It begs the question, how then does a "dino" oil become multi-visc ...and NOT be synthetic ?
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Most modern "synthetic" oils are basically dino oils with group 3 base oils, it used to be that group 4 oils, or PAO oils, were only considered synthetic. . A lawsuit decades ago between Mobile 1 and Castrol changed that definition.

https://blog.amsoil.com/are-all-synthetic-oil-groups-the-same-group-iii-vs-iv-vs-v/
 
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potownrob said:
the thinner oil is said to be noisy though. it sure was in my n/a engine. i switched to maxlife synthetic blend for this last oil change (supposedly the same viscosity? didn't realize a 0w-20 blend even existed), and the engine is running MUCH quieter than before.
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Yes, it makes a huge difference. I could tell the difference as soon as I started the vehicle for the first time with the 5W-30. Much quieter.

High frequency hearing varies and some people will be able to tell more of a difference.

For me, the car sounds much more refined with that quieter engine. It's basically a free upgrade.
 
I don't doubt that 5W-30 is quieter than 0W-20 when all other variables are controlled, but even just changing my oil from the factory fill to PUP at 1200 miles resulted in a slightly quieter engine.
 
N7turbo said:
I don't doubt that 5W-30 is quieter than 0W-20 when all other variables are controlled, but even just changing my oil from the factory fill to PUP at 1200 miles resulted in a slightly quieter engine.
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Yeah, that's the factory fill. I bought the car in 2019 and didn't switch to 5W-30 until 2022.
 
Honestly - Im not 100% convinced of the switch to 5-30 == and yes aware its used in the same engine in other countries - Toyota has recently begun using a 0-16 and the jurys still out on this issue- Im know that I will get hammered by most here - but I looking for more scientific data than just" its quieter "--and Im certain it is - So we know multi-vis has two fundamental components -- startup temp viscosity and normal operating temp viscosity- hence 5 start-up and 30 operating ( for simplicity's sake )- Im only 10K into a new engine and 2 oil changes - My mileage is great and its winter now , so I figure with sub-32 degree start-ups Im ok with the 0-20 for another minute or two - But would like a compromise of sorts when summer arrives -- say a 5-20 ? - Im looking for the full spectrum of benefits here -- will the mileage improve ? Will it protect the engine better ? Im on the fence and may get it to a good break in mileage of about 25K miles and then swap to the 5-30 --
 
Ford switched from 5W-20 to 5W-30 in all of their 3.5NA 6-cylinder engines. EDIT: Also in all of their 5.0L V8s.

Just some anecdotal information. It has no bearing on which oil I choose I just find it interesting.

Mazda says that either grade of oil is acceptable, so use the one you want.

1704420271269.png
 
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I”ve run Mazda moly 0W-20 since new. No noticeable oil consumption between 5-6K mile oil changes. Just staying the course for now.
 
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