alxmaverick

Hi all, after searching I couldn't find the answer so I had a few quick questions.

I have a Mazdaspeed3 2008.5 @ 10k miles.

I'm taking my car into the dealer for an oil change and asked what they use. They said they use genuine "Mazda Oil". I was wondering if "Mazda Oil" was any good and how it compares to other names on the market (or if it's just another brand with the Mazda logo slapped onto it). Does anyone know what "Mazda Oil" is and how well it holds up against other brands? Should I bring my own?

What is also disturbing was that the tech in the service department was convinced the Mazdaspeed3 used 5w20 until I pointed out it was 5w30. I'm always nervous about oil changes because I don't really trust the Mazda center in my area (Alhambra) because they tried to screw me over when I was buying my car from a private seller. I had taken it into them for an inspection and when the dealer found out the low price, he told the seller that he'd give him $500 more to sell it to him instead of me. Luckily the private seller was a man of his word. Another confusing thing is that Alhambra Mazda charges $30 for an oil change whereas further out Galpin Mazda charges $45 for the same thing.

Lastly, I know there's tons of questions on this but is it too late for me to change to synthetic at 10k miles? There are conflicting arguments about "break-in" period. As I live in Los Angeles and the weather's always nice, what kind of improvements will I see if any? (i.e. gas mileage, etc)

Thanks a lot guys!

gio64

I have actually asked about Mazda Oil myself. I own a 2010 Mazda 3 and did a 500 mile oil change moving to synth. They did say to me what brand it was, and i cannot remember, however, it was a re-branded well known oil company oil (something like Quaker or Castrol or the likes).

Bringing your own oil will make the process a bit cheaper or as expensive but with better oil in your car, at least that's my opinion, I would think they'd charge you for oil more than what you pay for it yourself (in this respect, the service clerk kind of hinted to me that it was the case).

What you mention in relation to your dealership is really sad. I understand you not trusting them, however, it would be a very very low blow to deliver the wrong oil in the car on their behalf...

I don't exactly know how bad (or irrelevant) it would be to change the oil in the car to synth at this point. Realistically, if your year model has the same oil change intervals as mine (8k kms/5k miles), any average guy would have changed the oil in the car once at 5k and now would be going for the second oil change. Given that the oil in it wasn't synth to begin with, your car would be driving on mineral 5k miles more than what your average guy would drive his, as they would probably go in for the first oil change at 5k and switch to synth.

Personally, like I stated, I went in at 500 miles and went synth. That early change would be advisable regardless as the first 500 miles do constitute a lot of break-in wear and taking that oil off quickly helps with the engine durability and performance in the long run.

In regards to the improvements, the synth is simply an oil that offers a better and longer protection. Basically, all else being equal, synth should make your engine last longer. The biggest problem with oil is breakdown and durability. Synth provides stronger resistance to breakdown and longer oil "life". So you are keeping a safer margin between your engine and wear due to oil inefficiency.

Gas mileage depends primarily (at least as far as oil is concerned) on viscosity. So, if an oil has a certain resistance to flow (viscosity), whether or not it is synthetic, is not important, what matters is how easy it is for it to flow.
In this respect, lately manufacturers have started recommending W20 oils in place of W30. This is because a thinner oil yields better mileage. Not much, really, but for a company that has to meet government standards, it is indeed an important difference for them to meet the mileage points.
a 20 oil is not good for your average engine. But a lot of the manufacturers do recommend 20. My 2010 3 is supposed to run on 5w20. I went in and asked for 5w30. In the owners' manual it states that 30 can be used when 20 is not available.
I read that Chrysler lately has changed their specs on their cars because they have had many problems with new engines that had left the factory with a "5W20" oil spec. They traced the problems back to the oil and issued a typically political statement saying "5w20 should only be used for breaking-in the engine, then 5W30 oil should go in. Most companies will recommend 5W20 for a given model car in North America and 5W30 for the same model car sold in Europe, where they don't have to meet the mileage standards. Something to think about.
Other than that, oil won't change anything. I believe Royal Purple claims that their oil improves the power output by reducing friction within the engine. While they do have special friction additives, its makeup is not as complete as other oils. I have always preferred Mobil 1 over anything else and my preference is the same as somebody I have met over car forums who is very knowledgeable in this matter.

I hope this helps somehow.

alxmaverick

Hey Gio,

Thanks a lot for your detailed response! Yeah it sucked what I went through but you helped put my mind at ease about the Mazda Oil brand, and even if they put 5w20 it doesn't sound like it'd do any permanent damage so it seems okay there. Haha I'm still going through that "babying" stage with my Mazdaspeed right now even though I'm already at 10k miles.

You make very good points on synthetic oil, I'm just wondering if it's worth the trouble of buying it myself since there's soooo many threads on it and everyone's mileage is different. I just recently found out about it but would like some more empirical proof that my engine will last longer (by how much?) as I couldn't find many reports about it online. One of the things holding me back is I can't seem to figure out what all the dealers I asked about synthetic advise against it.

Once again, thanks for taking the time to break it down and explain it to me!

gio64

No problem, whatever I can do to help, I am happy to do.

Just keep one thing in mind however, that is that 5W20 IS BAD, period. In the example I mentioned, about Chrysler, they had engine failures because of that. What happens is that the oil breaks down and your crank runs on the bearings, scores them and there's your permanent damage (this is just an example). You are driving a turbocharged car. I own one as well (93 Mazda RX7). Any turbo car requires that you take special care about some things and the oil is one of them. The oil runs through the turbos to lubricate the bearings and also to cool it down. When the oil is going through those turbos, it reaches temperatures that are seen normally in the sun (kidding, but you get the picture). Not having a good oil means killing turbos and engine. You HAVE to use an extremely good oil and you HAVE to change it often, because it goes through hell when it goes through the engine and then it goes through more hell when it goes through the turbo (or turbos, in my case).

On a side note, one thing you should always do if you own a turbo charged car, is to allow the turbo to cool down after some spirited driving. This is achieved by driving for a few minutes off the boost, then letting the car idle for a short period of time before you actually turn it off. The reason is that if you shut it down hot, the oil stops circulating and the one in the turbos sits right there. The high temperatures will cook the oil in the bearings and will destroy them quickly, causing the turbo to need a rebuild or a swap for a new part ($$$$). Letting the car run for a bit off the boost brings the turbo temps down and that helps the oil to stay alive.

Another thing you want to do is make sure you don't beat on it until the car has fully reached operating temps. This is just bad for pretty much everything other than the tranny.

alxmaverick

Thanks! I always wondered what the cool-down time was about. I do idle my car after spirited driving but I was curious why it needed cool down since if I shut down my engine it would automatically cool down over time anyways. Now I know that it has to do with the oil inside the turbo

So I spoke to the dealer after getting my oil change and asked why they discourage synthetic. They said it was because synthetic oil will cause "knocking". Is there any truth to that?

Thanks!

gio64

No problem, that's what the cool down is for, anyway. There are some "counter effects", depending on the cars. With the FD (RX7 third gen), since the car is notorious for generating industrial amounts of heat, you don't want to use something like a turbo timer, because you'll heat up to oblivion everything under the hood and risk with coolant seals which are the weakest link in a rotary.
I would say that after having fun, if you drive on a highway off boost for 5 minutes or a bit longer around town and away from traffic, then you stop and let it idle between 30 and 60 seconds, you should be OK. But look into people who own your very car, they'll be able to probably come up with more precise figures.
Cooking oil onto the bearings is really a problem, I don't know about the Speed 3, but the RX7 even has coolant lines going into the turbos (IIRC) and it's still not enough to keep the temperatures down, so...

Now, regarding your dealership.
I might be unaware of something major here and therefore be wrong.
However, as far as I know, that must be the biggest piece of idiocy I have ever heard in my entire life.

Engine knok is caused by fuel igniting in the combustion chamber (so, between the top of the piston and the ceiling of the engine head) while the gas-air mix is being compressed (in the "compression" cycle) and before the spark actually fires it up.
The last time I checked, cars don't use oil in the combustion chambers and if they do, there is something wrong with the engine (leaking from valve seals, piston rings etc.).
Now, oil, any oil, doesn't burn as easily as gas. We would be filling up with oil if that were the case, not with premium unleaded. If you hypothetically speaking think that some of your oil is getting in the combustion chamber and it's getting burned by the combustion cycle, I would have that checked.
I did look into the oil causing knock. It seems that some hold up to that idea. Well, any oil, that is, not synthetic oil. As far as I am concerned, I would like to see some scientific explanation of how this takes place.
The best thing I can come up with is that oil burning in the combustion chambers leads to increased carbon deposits on top of the piston. What carbon deposits can and possibly will do, is that they will increase the compression ratio of the engine (they reduce the space between the piston and the engine head as they layer themselves on top of the piston) and this can lead to extreme compression levels that favour pre-ignition (even more so in a turbo-charged car). Together with that, they could have some irregular and sharp ridges, which will stay very hot and can act as a spark plug themselves, igniting the air fuel mix ahead of time.

In the light of this, the only way that your dealership statement could make any sense whatsoever, is that if you are leaking oil in the combustion chambers in large amounts (and burning it), the tendency to create carbon deposits due to oil would be higher in a synthetic oil, than it would be in a mineral oil.

This is really something that would have to be confirmed by somebody, but I really don't know why that would be. Just keep in mind this: when the RX7 came out (1993) Mazda discouraged the use of synthetic oil because it doesn't burn as clean as the mineral counterpart. This is no longer true with modern synthetic oils.
Besides that, keep this in mind: the rotary engine has an "oil metering pump". It sucks oil from your oil pan and squirts it in the combustion chambers (I am keeping the explanation simple here) to keep the apex seals lubricated. BY DESIGN FROM MAZDA the rotary uses the oil and burns it. It is not much, however, you do need to replace it as you drive the car. It is reasonable to think that if you are going to burn oil by design, you want to make sure that what you regularly burn is not going to pile stuff up on the rotor faces.
Just FYI, there are plenty (probably the majority of the owners) of rotary users who have switched to synth after they put a new engine or rebuilt engine in their RX7s and have never had a problem with it.
This is not so in a piston engine. When you are using oil, you have a problem. Your cat will clog and stop working. You'll be polluting like crazy. Knock would not be the first thing on your list.
And -like I said- modern synthetic oils burn as clean as a mineral oil.

To be honest with you, I think that dealership is pretty strange. Even if you were to take my hypothetical explanation of that statement they give you to be perfect and accurate, making therefore their statement right (or at least comprehensible), I would never approach you and tell you straight up "synthetic oil causes detonation", without at least giving you a better explanation.
Just have a look at race cars, find out what engine oils they use. Then ask yourself if they would chance "knock" or not.

alxmaverick

Yeah I thought it was weird that they said it caused knocking and your explanation detailed how oil type should be irrelevant to piston timing. I'm going to call them back and see if I can get a better explanation.

Thanks for the detailed explanation, whew I learned a lot today!

channelv

What is your climate? If you're not in the way north, I'd recommend the Mobile 1 0w-30, less friction and proven better mileage too!. Otherwise if you live north, use Mobile 1 or equivalent synthetic 5w-30. Castrol Syntec is a blend of Synth and dyno oil. Choice is up to you.