Oil Weight, Type, and Change Frequency re: Warranty Claims
 

I have a year left on my 8 year/100k miles engine warranty (I have a 2007 6MT that wasn't sold until late 2008).

I have a very slow coolant seal failure that causes all of the appropriate symptoms at startup if I leave the car sitting for several days in a row. I plan to send in an oil sample to Blackstone labs to confirm, and then see the dealer about installing a reman under warranty (hopefully).

So, assuming I am correct and the Blackstone test shows coolant in my oil, my question is as follows: what will the dealer require with respect to service history on oil changes? Since buying the car ~14k miles ago I have done all of my own service to the car. I believe I've changed the oil either 5 or 6 times in total, just need to dig up receipts.

With my car being a 2007, will they have any issues if the oil used was not 5w20 dino? Say, for instance, that synthetic mobil 1 5w30 and synthetic rotella 5w40 were used?

And what about frequency? Will they only require receipts for 2 changes (per the 7.5k mile interval recommended in the manual)? I think i can dig up all the receipts but not positive.

I can't even think why oil type/weight would have a meaningful impact on this type of failure - so I think I'd be fairly safe citing the Magnusson Moss (spelling?) act. Let me know if any of you disagree.

Also, if I flushed my own coolant and changed to something other than mazda coolant (say Prestone/distilled water 50/50, for instance), could they try to say this caused or contributed to the coolant seal failure?

I also have a coolant reservoir sensor failure, so the light is always on. And my rear bank o2 sensor is bad. I'm just trying to dot my i's and cross my t's before going in. Don't want any issues coming up where they could try and void the warranty on me.

Thank you all in advance for your help!!

EDIT: I should also note that I brought the car into a different dealer just under one year ago to complain of the same symptoms (which actually somehow improved over the summer but are now returning). They were not able to replicate the symptoms (because the car needs to sit for ~48 hours for enough coolant to drip into the housings) and thus weren't willing to help me. But, bottom line, if it is of any relevance, I will be able to show that I've been complaining of these symptoms for a long while.

Yes the extended warranty states you must be able to prove that you maintained the engine in accordance with the factory schedule (so if you changed it more often that is fine). And they can deny you for not using the recommended oil, it just depends if the dealer wants to be a PIA. On my first replacement they didn't ask for anything, on the last one I got at 96,000 miles they were being bitches about it. Nothing that a payoff to a Jiffy Lube employee couldn't fix though :) And they will need to confirm the coolant seal leak as well. A cooling system pressure test should confirm that.

Thank you sir. What about the prestone coolant and bad coolant reservoir sensor? Any other things I should be thinking about?

I have no direct experience with this, but I would not leave anything to chance, considering what you have at risk. It does not cost too much to replace the coolant bottle, so I would. They could claim you damaged the engine by running it with low coolant since your sensor is broken. I doubt they have any way to test the coolant to find out what you used, but for future reference, there are only a handful of coolant types that are free of certain chemicals that eat silicone seals. There are threads discussing this.

You can enter your oil change information in the MyMazda web site, which may help you some if they are casual in their investigation. I keep all my oil change receipts in my glove box--whether I took it some where to have it done or did it myself. The receipts might be important. You should be OK on oil type. While dino 5W20 is recommended in the US, synthetic 5W30 is recommended in other parts of the world.

It all depends on the dealer, like 9k said. When I needed a new engine, he asked me to get him records of maintenance changes, and I pulled up my maintenance record on MazdaUSA.com on my tablet, handed it over, he looked at it, asked for a copy, I saved the web page off as HTML and forwarded in an email. He got it moments later and accepted it. No hassle at all.

Others aren't so lucky.