I was going to take my 2007 RX8 to the dealership for an oil change, when I got a nice big screw in the sidewall. Instead of driving all the way to the dealer 10 miles away, I drove to my local Firestone, where I bought my tires a month earlier. I figured while they were replacing the tire that I might as well have them change the oil as well, instead of driving all the way up to the stealership.

It's been two weeks, and I just looked at the window sticker for the oil change and it says Synthetic Blend. I checked the paperwork, and they indeed refilled it with a 5W30 Synthetic Blend oil.

Now first and foremost, is this going to void the warranty on my engine? If I ever when I someday have engine trouble, will this prevent Mazda from covering the repairs? Is this type of oil not ideal for my engine? Does this mean I have to throw away the case of regular 5W20 I bought to top off at every gas fillup, or can I keep using that?

The whole point of going to a dealership/mechanic to get the oil changed, is to keep the warranty in good standing, otherwise I would just change the f****r myself.

I'm soooo pissed that they didn't ask me about switching to a synthetic blend.

Any insight you could provide would be much appreciated.

 

https://www.rx8club.com/rx-8-discussion-3/submitting-bbb-claim-help-needed-191010/

That guy's warranty claim for an 04 with a /weak failed rotor was denied based on your exact situation! I would go back to the tire place, manual in hand, and demand some Castrol Dino Juice. Since it's a blend, and I know some some people here swear by particular synthetics, then you may be okay, but others are free to contradict my mere 20 years of being a rotary dilettante.

Again, another example that only those with the requisite knowledge should lay hands on cars. This may actually disqualify me.... meh!

Bon Chance!

 

Say 'Thank You' to Firestone, and move on with your life.

There is absolutely nothing wrong, either with the weight being 5w30, or the fact that it's semi-syn.

Keep the bill for warranty and sleep easy, there will be far more interesting things in future to worry about.

S

 

I have used synthetic for as long as I've owned my car and have had no issues with it thus far. 78k miles

 

Go back and make them change the oil to conventional, giving you a receipt for that.

Or at least just a receipt.

You can keep using your case of 5w20. Nothing wrong with mixing different grades.

Ken

 

Go back and make them change it to FULL synthetic.

 

Doesn't surprise me. Firestone has a good track record of bad service. If it weren't for corporate contracts and little old ladies they would folded years ago.

 

I am the last person on the planet that stands out in the garage and watches them do an oil change on my car? I'll BS with them a bit, but I'm watching them like a hawk.

 

perfectly put

 

Take it back and make them change it or just change out the oil sooner than later. 5W30 is a better choice for the car anyways.

 

I would suggest that they change it out or just print out a new receipt for dino, so you have proper records, you don't wan't problems with you warranty, imho.

 

mazmart has concluded that if you run dino for 80k+ miles then switch over to synthetic, it can contribute to an engine failure. most happen 20k-30k miles after switching. the reason being is that synthetic will clean out lots of carbon deposits that were holding in compression.

however...

1 oil change is not going to hurt you.
2. as a 2007, i doubt you have that many miles
3. if you have below 40k miles, you should consider the switch permanently

 

I think I've read another thread (by someone buying an 8) confirming that Mazda will void the warranty for using synth.

 

go back and change the oil for the one you want... easy

 

there are fellow drivers on here using synthetic, i wont say its better/worse.. but 5w30 weight is good. Its standard in all 8s worldwide except US, it'll be fine.

 

anyone who gets their warranty denied because they used synthetic is an idiot. I'm sorry but Mazda doesn't have a special machine that instanty analyzes oils for viscosity / type.
If knowingly used synthetic and knowingly submited invoices that reflected this....well....guess whose to blame.

there are TONS of people here who use synthetic with no problems.
if you're THAT UPSET that they put synthetic in your car then STOP GOING TO FIRESTONE, go to jiffy lub, pay $20 and have them "correct" the issue.
problem solved.

 

True dat son!! I haven't heard the word Jiffy lube in years. And they put synthetic blend in it cause that's what they have in there system as a recommended oil type for our car. Did you not notice the price diff

 

Agreed 100%.

 

Yep, gp back and get it changed to the regualr dino oil.

 

This is a huge WTF thread.

ALL 5w20 oil is at the very least a semi-synthetic blend.

 

But they do have a small cadre of service writers who know how to read.

When they ask for invoices, and the ones you have say synthetic, what do you do? The poor guy in the BBB thread had one invoice that said synthetic...along with NOTHING in his owner's manual or warranty documents that said no synthetic.

That's not the worst arbitrary warranty denial that Mazda has perpetrated. We have one member here (definitely not an idiot) whose entire warranty was voided because he posted here about having once driven his 8 over 100 mph.

Ken

 

you have got to be kidding me they voided a warranty because a car went over 100 mph?! there can't be any grounds for that other than he broke the law?

 

Yep, that's true. He is on the Mod staff.

 

My understanding is that synthetic blends are actually worse than dino oil or full-synthetic in rotaries, because the combination of slow-burning synthetic oil and sulfur from the dino oil basically creates a microscopic layer of vulcanized rubber inside the engine. It's nothing the seals can't scrape off, but it hangs around for a long time and builds up, unlike the "dry" soot created by burning normal dino oil. I don't know what the impact is of using full-synthetic, but since it doesn't contain any sulfur, whatever goop gets created during burn-off at least isn't reinforced the way tire rubber is.

As far as I know, the USA is the only country in which synthetic blends are routinely used, which may well be why Mazda tells its USA customers not to use any synthetic at all, to avoid gooping up their engines with vulcanized tar.

 

"creates a microscopic layer of vulcanized rubber inside the engine........"






Wow.









Just wow......