should I switch to 5w30 from 5w20? 2006 mazda 3 2.3L non turbo

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hey all,​

i have a 2006 mazda 3 2.3L with 100,000 miles mostly city driven for the past year or so. Been running any on sale synthetic 5w20 for the past 4 oil changes but not sure what it ran on as have only had it for 2 years. Pretty sure it had synthetic dealer oil in the past.

I have not noticed any issues with 5w20 but was wondering if I should start upping it to 5w30? our winters here in canada get super cold like down to -40F sometimes so ive been running 0W20 before the winter and was planning to run 0w20 again before the winter but not sure if running 5w30 this summer will be a smart choice since ill be coming down to 0wxx for the winter anyways

Let me knwo what yall think? or just stick with the xw20 until higher mileage?

thx
 
Curious what does the owner's manual specify?

Sounds like it's not burning oil with the 5W-20 otherwise you would have mentioned it.
I would try a 5W-30 in the summer just because I like to experiment.

-40F will be testing the limits of 0W. I would get a block heater in addition.
 
During the summer months it doesn't matter, In my dad's 2015 Escape with the 2.5L in the Central Indiana winter doesn't really make a difference whether it's had 5W30 or 0W20 in it, but where you're at 0W sounds like more of a must if you're not running a block heater.
 
We had a 2006 Mazda3 although the engine was the 2.0L. The car had ~170,000 miles on the engine when we sold it.
Our owners manual was just like your's and 5W20 was the ONLY recommended oil.
We ran 0W20, 5W20 in the winters & 5W30 in the summer months. As the matter of fact, I used 5W30 even in our winter and noticed no issues or fuel economy penalties between 5W30 & 0W20. However, Western NY State doesn't get as cold as -40
 
Let me knwo what yall think?

The cynic in me thinks this is yet another version of the "thick vs thin" topic that has no practical end.


The engineer in me wants to know why you haven't discussed any measurable criteria for your querry?
- do you have an idea of what methods and tools you'll use to properly quantify the success or failure of this quest?
- do you have any baseline data from the current lube so you would know if a different fluid was better or worse?
- do you realize that to get baseline data, it would take 30 UOAs and probably 150k miles?
- do you realize that to test a different viscocity lube it would take an additional 30 more UOAs and another 150k miles?
- do you know how to use statistical processing methodology to properly identify and reduce/eliminate other potential variables from skewing the data?
- do you have any idea the costs, time and gauge R&R challenges involved with tear-down analysis?


The long-time member in me wonders why another long-term member hasn't realized this is a moot point that has been beaten to death already.


The Mod in me thinks this is yet another viscosity thread that should have never been created, but will be allowed to continue so that inane conversation has somewhere to exist this week.



Those are my thoughts,
;)
 
If it doesn't burn a drop no real need. But i would do that. Run a 30 grade for the warm half and a 20 for the cold half.
 
It's completely reasonable to use a thicker grade in the summer and a thinner one in the winter in your climate. At operating temperature, a 5W30 will be the same viscosity as a 0W20 when the 5W30 is warmer by around 7 degrees C. The seasonal difference in the oil temperatures in your engine is probably greater than this.

The question then is, is it better to use 0W20 winter & 5W30 summer, or 0W16 winter & 0W20 summer? If the car often gets driven hard and experiences very hot oil temperatures, the thicker grades may give better protection. In normal driving in a temperate climate, there will probably be no benefit to using a thicker grade than Mazda recommends.

I live in one of the colder parts of Canada, and use a 0W20 in winter and 5W30 in summer, in a vehicle that recommends 5W30. I've got an oil temperature gauge to help inform my decision to use a thinner grade in winter though. You may want to just keep it simple and use 0W20 year-round. There's no law against mixing oil grades either. A 50/50 mix of 0W20 and 5W30 for your spring oil change would be just fine.
 
I've permanently switched from 5W-20 to 5W-30.

One reason was HTHS.

Virgin 20 weight oil's have a marginal HTHS = 2.6, but will sheer to a lower HTHS during an oil change interval.
Engine wear increases astronomically when HTHS drops below 2.6,
Google this: HTHS wear chart.

I never felt comfortable with 20 weight oils when engine was under heavy load, like with vehicle fully loaded with 8 passengers going up long inclines with engine temperature climbing and higher RPM's. When I learned there is no benefit at all to 20 weight oils besides helping the automaker's avoid CAFE fines, I permanently stopped using any 20 weight oils.

5W-30 is all I will ever use.
If any doubt, ignore the CAFE influenced owner's manual writers in the US, and download the same owner's manual from Europe / Australia for the same engine and see for yourself that if recommends 5W-30 or 5W-40.
 
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our winters here in canada get super cold like down to -40F
Where in Canada do you live that it gets to -40? It's very rare for it to get that cold. Even the Yukon, NWT and Winnipeg only get that cold once in a while while unless you're referring to wind chill also, which doesn't affect an engine block.
 
The Honda in my signature has 287,000 miles and has run 5W-20 for the majority of those miles. Last couple of changes have been with 0W-20 just to standardize the oil for all the cars in my house. It feels smooth as silk since the change to the 0W-20. It has never seen a xxW-30 anything. Currrent fill is the new Quaker State Ultimate Protection.
 
The Honda in my signature has 287,000 miles and has run 5W-20 for the majority of those miles. Last couple of changes have been with 0W-20 just to standardize the oil for all the cars in my house. It feels smooth as silk since the change to the 0W-20. It has never seen a xxW-30 anything. Currrent fill is the new Quaker State Ultimate Protection.
20 weight oil is safe. I am glad you've had good results with it.

Since 20 and 30 weight oils are the same price, and MPG is negligable between them,
I chose 30 weights for the higher HTHS protection.

If interested, you can google this: HTHS wear chart.
The wear chart which shows engine wear go up exponentially when HTHS falls below 2.6 is what convinced me to make the permanent switch to 5W-30. Within the 5W-30 range, HTHS range is 2.9 to 3.5. I try to choose a 5W-30 with a higher HTHS in that range.
 
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I don't understand why some people think that the owners manual, vehicle manufacturers, engineers or experts would ever lie to us. That has never been the case before, about anything, ever! If the manual says to melt a stick of butter in your crank case you better do it like a good little slave okay?
 
The Honda in my signature has 287,000 miles and has run 5W-20 for the majority of those miles. Last couple of changes have been with 0W-20 just to standardize the oil for all the cars in my house. It feels smooth as silk since the change to the 0W-20. It has never seen a xxW-30 anything. Currrent fill is the new Quaker State Ultimate Protection.
Curious minds would like to know what was the average length of your OCI?
 
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