Wow - and here I was just looking for a post that might say something about tefloning the engine after break-in. I've done it to my last 3 vehicles and they have lasted forever (well, until I handed them over to my kids or buyers - one I'm still driving). Anyway - it makes sense not to burn synth just because of cost, if it's going to be consumed, it'll have carbon embedded as soon as it's introduced to the engine, and the statements about deposits being left behind make sense, also. I keep pretty good records and enjoy working and maintaining my own vehicles - I know what's being done and how, that way. But - I gotta say I was surprised to read in this thread that only about 4 - 1/2 qts. will come out while the remainder stays in the circulation system? Wow, again.

We just got our Rx a little over a month ago and the elation of the exceleration response has consumed a little over a half a quart at 1150 miles.

And that makes me think of the original question which had me looking for other owner's experience:

The point of using a lighter weight oil was to deliver it as quick as possible since startup is when the majority of damage occurs - and that's my reasoning for treating the engine with a teflon bonding product. Not Slick50 or the other ones you can but premixed, but I buy a pint of the straight PFE additive from a local parts store and I'm very happy with the experiences I had in doing so. Is there anybody that would advise AGAINST doing so?

And in a prior thread I read about the "Tornado" air intake add-on. While I feel it made a difference in my Tacoma in mileage alone, I wouldn't want to add this to my Rx. I'm glad I caught that one......

Man, can't wait to learn more, y'all.............

Tall...........

 

No, actually it does NOT make sense to avoid synthetic because a very teeny amount of oil is burned - out of about 7 litres in the system, you might burn 1 or 2 litres in 5000 km? Synthetics provide much better protection for lubrication; I wouldn't want to drop down to mineral oil just to save $3 or so on the oil that's combusted. Further - the idea that synthetics leave behind deposits is nonsense - they burn cleaner than mineral oils.

The point of using a multi-grade viscosity oil is so that it's lighter than a single grade when it's cold, providing better protection at startup. The viscosity of a 5W20 and 5W30 is IDENTICAL when cold - the first number(5) is the cold viscosity, the second (20 or 30) is the hot viscosity.

For me, personally (mechanical engineer), I would never use any sort of additive in the oil - DuPont themselves will tell you that Teflon additives are useless in engines at best, and possibly harmful (I believe it's even on the DuPont Teflon information web sites).

Regards,
Gordon

 

ok, that's all fine and said, but sometimes I'll need to see results in documented lab testing - being the skeptical guy I am. I read so many different opinions on this subject, it gets to be very confusing. And not like I'm never wrong, but I do rely upon personal experiences and be it either the advance in automobile manufacturing technologies or compositions of engine block alloys or whatever - I keep all my autos well into 10 years plus. The engines that have lasted the longest without oil consumption have been the ones that I have treated every 50,000 or so and have been a big fan of Castrol GTX 10W40. I had a 86 Pontiac that I experimented with nothing but Mobil 1 in it it's whole life and it did wonderfully until I gave it to my daughter. No visible varnish or deposits that whole life I had the car. I made my '76 Astre (a Pontiac version of a Vega) last 179,000 miles on its original engine - an almost miracle from what people saw me driving it would say. Maintenance pays for itself.

You see, like others, I'm sure - I really love this Rx and have plans to keep it forever (well, while I'm walking or should I say zooming around this earth). I just want to make sure I'm doing the right thing to my baby.

I will go out and keep looking at all the information and articles and test results, but the sake of argument is not enough to make me go one way or the other concerning synth or dino.

I would want to know what Mazda's warranty states I can or cannot use, and I haven't read that thread or seen any manufacturing statement, yet. Not that it's not out there, I just haven't seen it. I mean, they engineered the dang thing........

Tall..........

 

Mazda requires 5W20 (in North America - everywhere else, they spec 5W30), with API spec SL. That's it - no mention of not using synthetic.

Re burning synthetic, etc. - there are several comparative studies on the internet with dozens of synthetic and mineral oils analysed and detailed results posted. A good place to start is www.bobistheoilguy.com .

Regards,
Gordon

 

I changed to synthetic oil but now Mazda states thatthey do not recommend it. How can I change back to conventional oil. I hear that once you go synthetic, you can't switch back.

 

You people have mw so confussed i know alot of you have had yor cars for some time now i just bought mine 1 week ago a 2005 AU TRAN i am so confused on the proper oil to use please let me know if you have had this car now for more then 6 months. I don't want to make a mistake.
Thanks

 

This is (and always has been) a very controversial topic. You will get several different answers to your question.

For me, it all comes down to this.

If you keep your oil level full and changed routinely, you will never see any real difference between synth and dyno (non synth) oil. I am very picky with my car, and drive it real hard. I use valvoline 5w20 standard oil.

Somewhere along the way Mazda recommended using non synthetic oil for the rotary, without really explaining why. Some say its because dyno oil burns easier than synth oil does and the rotary engine burns oil by design.

I was involved in a few articles for RXTuner magazine which required me to follow a Racing team's progress with the RX8 in SCCA. This team has had years of experience with racing RX7's. If you want to see a rotary engine pushed hard, try 45 minutes of full throttle at 8500 RPM's in the heat of summer. They use synthetic (10w30 I believe) without any problems.

My advice is to use a quality oil at the 5w20 weight. Keep it changed and full on the dipstick. Beyond that... dyno or standard.....use what makes you feel better, because I won't make any discernable differce throughout the life of you car.

 

Why are you confused? Go by the manufacturers recommendations in the owners manual that came with the car and you can't go wrong. Simple.

You will NOT get a definitive answer on this forum to the question of what kind of oil to use. The topic has been debated on this forum ad nauseum, so if you really want to delve into the topic, do a search and spend the next couple of days reading all of them. In the end, you will be just as confused as you are now.

 

thanks guys

 

Don't worry about it. You can mix any brand or weight of oil with no fear of damage.

The only concern might be if you were to switch to synthetics at a high mileage. You might start to see some leaks.

I used to have a Mustang Cobra that had used Moble 1 since it was new. It had developed a couple of small leaks that weren't worth the cost of fixing. At 140,000 miles I changed to regular oil and the leaks mysteriously disappeared. When I researched this on the internet I found that quite a few other people had the same experience.

I recently sold the car with 215000 miles and it was still strong. So half it's life was with synthetic and the other was with regular oil. But I always changed it regularly.

 

Well, I've read every thread on this forum I can find about oil, brands, changes, synthetic vs. petroleum and I have to agree with Gyro, "Use a quality oil at the 5w20 weight". All this reading and trying to decipher what is best just hurts my brain. I'm going to buy a case of Valvoline or Castrol, whichever cost 2 cents less and not read another thread about oil changes.

I will do as Charlie "marietta_8" of Mazcare in Marietta, GA suggested to me the other day; purchase Mazda oil filters, tear the top flap off and write the date of the oil and filter change on it and file away in records for warranty purposes.

Now, I'm done with this subject!

 

Motorcraft 5W20-1 quart about evey 1500 miles-factory fill i think-can't be all bad!

 

i have had my RX8 now a few month i found that they have castrol 5w-20 partial synthetic oil i think this is what i will be using it was around $11 for a 5Qt container just thought i would pass the info along.