Is the CX-5 Dip Stick Calibrated for Hot Oil temp? It would explain a lot

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
I changed the oil on my 2018 CX-9 yesterday.

Oil level check after letting the car sit for about 12 hours. Did a pull, wipe, reinsert, then pulled again and took the picture.
View attachment 227186

After 30 mins of driving, this is the oil level check 6-7 mins after vehicle shutdown (as recommended by the manual).
View attachment 227187


It's a little hard to see, but there is a difference in the oil level shown on the dipstick.

So what does this mean? Well, IMO it means that reading your oil when cold results in a higher reading than when the oil level is read according to the manual. So let's say the dealer were to do an oil change following the procedures in the manual, then top up the oil so that it's right at the "Full" mark. Someone who checks the oil while cold might think that the dealership overfilled the engine, when they actually didn't.

To be fair, judging by the difference in levels, the "overfilled" amount is nothing to be concerned about IMO. This also means that if you do check your oil level when cold (and top it off to the "Full" mark when cold), then your oil level when read according to the manual would actually be a little below the "Full" mark. Again, nothing to be concerned about.

That's my interpretation from my experience with my engine.
So your observation:
⋯ So what does this mean? Well, IMO it means that reading your oil when cold results in a higher reading than when the oil level is read according to the manual.
And your statement in post #91:
⋯ Basically, OP saw posts about oil being "underfilled" from factory, and posts suggesting that oil needs to be added upon delivery. After confirming that the oil level in his GT Reserve (not 2.5 NA) is at the MAX line when cold, and above the MAX line when level is read using the procedure outlined in the manual, he suggested that those posts were actually wrong, and that people may have been checking their oil levels incorrectly.
They totally contradict each other.

And the statement from OP:
I have a new GTR and brand new to this forum.

FWIW, if my thinking is correct, a lot of the DIY oil change posts here are getting things wrong. They may acctually be overfilling. Max on a cold fill should be lower than MAX. Maybe just putting in what MAZDA says is the right capacity for your engine is where you should be filling your oil regardless of whether it hits MAX on the dipstick or not.
Which also contradict your observation too on the 2.5T.

So your claim in post #91:

@Steve88 has not replied with an answer from Mazda, but based on the procedure outlined in the manual and the fact that the 2.5T's engine uses a different dipstick than the 2.5 NA, I think it's fairly safe to come to the conclusion that the 2.5T dipstick is calibrated for hot oil temps.“

should be false too? ;)
 

sm1ke

Work In Progress..
Moderator
Contributor
:
Canada
:
'18 CX-9 Signature
Like I said in my post and in previous posts before it, filling it to the max mark is a preference, not a requirement.

Exact numbers are never truly exact because you have to account for tolerances. Tolerances need to exist to make manufacturing as cost-effective as possible (this is a Mazda, after all). Judging the engineering competency of Mazda based on whether they provide an exact number for torquing a bolt vs. a range is just ridiculous. Torque it to the average of the range if it matters to you so much.

If you feel you need to drain out every last drop of old oil and refill it to the max line and nothing less, then yes, the 4.8L specified in the manual could be considered "wrong". But again, the problem with thinking this is that you assume EVERYONE changes their oil the same way that you do, in the same conditions that you do, which obviously is not the case.

I've said this before - unless Mazda provides more specific criteria for doing an oil change, they shouldn't be expected to provide an exact number for the amount of oil to refill. They do not specify how long to drain the oil, whether to remove the filter before replacing the drain plug, whether to prefill the oil filter, etc. Oil dilution/consumption is another potential factor that could throw your expectations off. Because of all of that, using approximate fluid capacities is actually more realistic than an exact number.
 

sm1ke

Work In Progress..
Moderator
Contributor
:
Canada
:
'18 CX-9 Signature
So your observation:


And your statement in post #91:

They totally contradict each other.

And the statement from OP:

Which also contradict your observation too on the 2.5T.
The statement I made in post #91 was just paraphrasing what Steve88 wrote. As shown in the post above this one, my actual experience was different. So yes, you're right, my experience and Steve88's experience are different.

In my experience, the oil level when cold reads slightly higher than when it is read according to the manual. I checked again today with the same results.

Steve88's experience was the opposite. Oil level when read cold is lower than when it is read according to the manual.

I don't know why our experiences would be different, but they are.


So your claim in post #91:

@Steve88 has not replied with an answer from Mazda, but based on the procedure outlined in the manual and the fact that the 2.5T's engine uses a different dipstick than the 2.5 NA, I think it's fairly safe to come to the conclusion that the 2.5T dipstick is calibrated for hot oil temps.“

should be false too? ;)
The assumption I made could be wrong, sure. It could also be right. Do you have evidence to prove it one way or the other? Because if you do, we'd have an answer for the OP and we could put this issue to bed.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
As stated in the manual "all capacities are APPRROXIEMENT"
Would you call it “approximate quantity” when the actual capacity of the rear differential is 66% larger than given capacity on specs?
 

sm1ke

Work In Progress..
Moderator
Contributor
:
Canada
:
'18 CX-9 Signature
Would you call it “approximate quantity” when the actual capacity of the rear differential is 66% larger than given capacity on specs?
Maybe you're overfilling your rear diff ;)

I would not call it an "approximate quantity". In fact it sounds like there is an error in the manual. They list 0.37 qt as the capacity, but specify that the diff should be filled to the brim of the fill hole, which in practice, is about 0.8 qt. So either 0.37 qt is an incorrect value, or filling to the brim of the fill hole is not required.

Either way, this example is somewhat unrelated as the process specifies the quantity, and the direction to "fill to the brim". Rear diff oil change also does not have a filter that can be prefilled or not. Engine oil process simply specifies 4.8L per oil change, and the actual amount can vary depending on the person doing the oil change (again, prefilling filter, draining for 10 mins vs 1 hour vs overnight, filling to max mark, etc.).
 
Top