Greeting This post pertains to my wife's 2021 CX5 Signature with a 2.5T engine. After 44,700 miles and adding an additional 3.5 quarts of oil between oil changes Mazda agreed to changing the exhaust valve seals. My question to the group is does anyone know if the seals they use now are the same type of seals they used in the building of the engine or have they engineered a different type to eliminate the failure from occurring again? The part number of the seals on the invoice is PY8W-10-1F5.
thanks, Gary

 

I have the same car as you (bought new) so I've been following this issue for years. From what I've read, the original seals were not defective per se; they were just not the correct seals for that engine. I don't know if there's any truth in that, but my car has consumed a small amount of oil since new so it does not seem to be a matter that the seals are deteriorating. Model year 2021 was the only year that this particular issue existed.

I've got 52 k miles on mine and the oil consumption has actually gone down over time. I change my oil at 5k intervals and find that I am only adding about 8-10 ounces of oil after 2500 miles to keep it topped-off. My low oil light has never come on but I check the oil level regularly in all of my cars and top off as needed.

 

This was answered on a few forums by a few of us that were/are in the engine building service part of the auto industry.

Apparently comparing the seals there were no engineering changes done ....

but they do have a new part number 

I still have several both new and replaced seals from the MAZDA service warranty on hand and actually was going to toss them, but I guess as this is getting to be a "dust off" revived subject will hold onto them a while longer.

This was the last info I have and may have been updated with a TSB I am not aware of or every received: I should also add that no defect in the head vale seats, valves, valve guides, or the first casting and machining of the head casting assemblies. was found to have any defects that was noted or from any Mazda dealership that did the valve seal service. That was mentioned in any service update. In fact, unlike some parts replacements under warranty Mazda did not require the dealership to hold on to the removed parts replaced or return them to Mazda corp. In other words, toss them as old parts waste materiel disposal.

The actual reading the TSB suggests that only a small number of effected engines may have the issue. Unformtuantly this TSB which are designed and written specifically for MAZDA service departments was passed around various Mazda forums and like most misunderstood and set a president for Mazda owners worrying that they may have the issues outlined in the TSB.

While I am not suggesting that the problem did not exists, I will state the number of actual problematic engines having extreme oil consumption vs numbers of produced engine in the effective year range was very in fact extremely low.

I would suggest and recommend that if anyone is actually worried to simply monitor your oil level on the dip stick in a proper way. I say proper because again most really don't know how to read or understand the 2 lines on the dip stick. So the first thing is to learn how to read a Mazda dipstick on the Skyactiv engine. If you do actually have oil loss that is not from a leak and is showing other signs or you feel that it is "burning" oil then go to your dealership and have the service department evacuate your engine. Don't be surprised if they can't find any indication of oil burning but at least your concern will be logged on your VIN. Then it will be up to you to monitor the oil consumption if you actually have one and to what degree. This goes back to learning how to read a dip stick!

In closing I am qualified to do warranty service on Mazda's with few exceptions however in our shop we will not do many Warranties like the replacement of vale stem seals. the service TSB is very specific about what parts are covered. This means that doing the service if other parts are needing to be serviced or replaced at the time they may not and often are not covered under the warranty service and the owner must pay for those parts and also a possible labor fee.

 

I posted this in another thread as well. My '21 2.5T just started burning some oil past 30k miles. It didn't use a drop up to the 30k oil change (I also do 5k changes). From 30-33k it went down slightly from the top hole of the dipstick (measured on a cold engine) and I added about a 1/10 of a quart to get it back to the top hole on the dipstick. I then drove another 2k miles and when checked just before going in for my 35k change, it had again dropped slightly from the top hole (less than it had dropped previously, but it was definitely down a bit). I asked about the TSB at my dealer and was told the car had to record a low oil level event for the TSB to be done. My plan is to let it drop over the next 5k miles and see if the light comes on before adding any oil. Then I will attempt to get the TSB done.

 

Just wanted to follow up on the oil usage pre and post valve seal replacement. Getting ready for my 7500 mile oil change since valve seals were replaced and I cannot see any difference in the level on the dip stick. Looks like my oil usage was due to the valve seals.

 

Good to read this with your oil reading observation on the dip stick so far.

It does not answer if the seals were any different nor did it indicate any information about the seal other than some of the seals were replaced? Do you know did they replace all or specific cylinder(s) ones?
And did it show (it does not have to nor is there a requirement) on your final work order the part numbers and any information about which seal and any other parts or service done at that time?

 

Castisto I listed the valve seal number in my initial post and my question to the Mazda forum was if anyone knew if this was the same valve seal that was used in the initial factory build of this motor. My invoice states that the dealership installed 8 exhaust valve seals. It also states they installed a Head Cover gasket.
Gary

 

We looked and could not find any measurements that deferred and the material used appeared to be the same . There was a slight diffent in the spring but no normal way to measure that. Our conclusion was it was likely a flaw in small number of seals. Because these are mass produced there is no way to track where defective ones went. Thats why the TSB was so specific because those were the reported suspected (never varied) VIN and or specific model production month and or year engines that may have the defective seals..
It’s not the first time an auto manufacturer has a superceded a part with a different number but the part is still the same part or with minor changes like simply the color .

Generally most dealerships get authorization to replace all the exhaust seals. They are also notified to dispose of them and not return them to the customer if asked. It would also be considered common since with any engine machines were there is a question about valve seals to replace the complete set of intake and or exhaust or the all of them.