Whats the wisdom here about how often the PTU fluid should be changed in my 2012 Grand Touring CX9 which I bought new? There is nothing in the manual about fluid change frequency. My PTU went bad at 35000 and was replaced under new car warranty. I then had the fluid changed at about 76000 at my own cost in April, 2021. The mechanic said the fluid 'looked good/ok'. A youtube mechanic (Brian I think) recommends changing every 30000 bc of heat exposure. The range for changing fluid that I've seen is 20000-70000. What's your alls opinion on frequency of fluid changes?

thanks

chuck
Reading, pa

 

Knowing the multitude of PTO failures on CX-9s, for peace of mind, I would be changing the oil ever 25,000 miles.

 

2nd Gen CX9s too? I have a 2022, gunna do an intake valve walnut cleaning at 50k but I didnt know about sketchy PTOs.....

 

Absolutely ^^^^^^ this is about the recommendation I give as well. Most applications the fluid gets cooked on a ongoing basis. Not sure why it is not under the regular maintenance schedules?

 

1st gen were notorious.

2nd gen appear to be ok, in saying that, for peace of mind I would personally change the oil every 24 - 30,000 miles.

 

How can the condition of the valves be inspected so the expensive cleaning is done only when needed?

 

Ya well ..... it will be fun to read what is answer is going to be lol
I tried to run my scope up the intake, does not really work well. So really you need to pull the intake. You can scope the cylinders but getting the scope to angel towards the intake valve is a PIA and very frustrating. Really doesn't work. LOL
If I see oil residue in the intake I know that carbon is trying to form its ugly black death and know it is either time to pull the intake and do a easy and very clean less mess less stress chemical spraying and wiping cleaning or up the use of my low RPM water injection for a few hundred miles. LOL

Here is the intake manifold. Scope that LOL

 

That's a good question. I was planning on either taking the intake off or running my scope in there. I've done a lot of hot section inspections on aircraft with my scope and I've never had a problem getting to where I need to go. But my guess is there's a correct interval that those valves may need to be cleaned. Doesn't seem like it's been established yet though from what I've been reading.

 

There has not been any mention of the Skyactiv engine with excessive carbon from being a DUI engine YET!. At least the engine that do not have other problems contributing to excessive oil in the intake manifold But I can tell you it does happen just not sure of what degree?
I NEVER SAID THAT IT COULD NOT BE SCOPED BUT THAT IT WAS PIA AND DOES NOT WORK WELL! (reading comprehensive may not be your strong point?)
If you look at the interior of the intake you might actually understand why it is a supreme challenge to get a scope through it and view the intake valve. LOL
Maybe grimreaper can help explain better what Mazda service technicians do.