# RX8 rotary engine failure **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [January 15, 2009, 2:06pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952 "2009-01-15T14:06:24Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![blackbelt](https://avatars.discourse-cdn.com/v4/letter/b/9de053/32.png) [@blackbelt](https://community.cartalk.com/u/blackbelt)\ **Post date:** [January 15, 2009, 2:06pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/1 "2009-01-15T14:06:24Z")
I recently purchased a 2008 rotary engine Mazda RX8. Now I’m reading all over the Internet that the only reason Mazda North America requires the use of 5W-20 weight motor oil is to meet Federal fuel mileage standards, and that the oil is too think to adequately protect the engine, resulting in early engine failure at 30,000+ miles. I have confirmed that in the rest of the world Mazda recommends 5W-30 weight oil, and have read documented cases from Australia of rotary engines lasting 200,000+ miles. Does anyone know if it is alright to use 5W-30 weight oil in the RX8, or would it void my warranty? ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [January 15, 2009, 3:04pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/2 "2009-01-15T15:04:14Z")
How long is the powertrain warranty on that car? If it is the typical 5 years/60k (or more) coverage, then at least you don’t have to worry about engine failure until the expiration of that coverage. Unless you can confirm from a reliable source (note: Internet sources of information are not necessarily authoritative or unbiased) that there are indeed many early engine failures in the US that can be attributed to 5W-20 oil, I would suggest that you stick to what is specified in the Owner’s Manual. ---
**Author:** ![oldschool](https://avatars.discourse-cdn.com/v4/letter/o/e19adc/32.png) [@oldschool](https://community.cartalk.com/u/oldschool)\ **Post date:** [January 15, 2009, 3:08pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/3 "2009-01-15T15:08:37Z")
You conclude that 5W-20 is thicker than 5W-30 (the word you use is “think”). 5W-20 and 5W-30 oils do have a difference but not one so great that engine failure at 30,000 would be the result. The 5W-30 may be the oil that is “to think” to protect the engine. Use what Mazda requires. On the practical side why would you admit to Mazda that you used a oil they don’t recommend? how would they know unless you told them? maybe you are just the “tell all” type. ---
**Author:** ![blackbelt](https://avatars.discourse-cdn.com/v4/letter/b/9de053/32.png) [@blackbelt](https://community.cartalk.com/u/blackbelt)\ **Post date:** [January 15, 2009, 3:46pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/4 "2009-01-15T15:46:41Z")
Apologies; typo. “Think” should actually be “thin”; the articles I read suggest the 5W-20 weight oil is too thin to protect the rotary engine, citing Castrol as stating on their bottles that their version of 5W-20 should only be used in vehicles that make short trips. ---
**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\ **Post date:** [January 15, 2009, 3:56pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/5 "2009-01-15T15:56:38Z")
The Mazda rotary engine has a well-deserved reputation for long life, often lasting 300K miles with normal maintenance (200K is nothing, really, to these engines). I’ve never heard this story about RX-8 engines lasting only 30K. The twin-turbo 13B engine in the gen-3 RX-7 has sort of a “hand grenade” reputation, but not the normally aspirated engines. Changing oil at the recommended interval is the key to long life with a rotary, and you can NEVER let one overheat. Other than that, drive it as hard as you like. I suggest you use the oil specified in the owner’s manual. Read it carefully, it may allow more than one multi-grade oil. ---
**Author:** ![andrew\_j](https://avatars.discourse-cdn.com/v4/letter/a/91b2a8/32.png) [@andrew\_j](https://community.cartalk.com/u/andrew_j)\ **Post date:** [January 15, 2009, 3:58pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/6 "2009-01-15T15:58:46Z")
I would highly advise you to use specified oil and check it often. The rotary engines have a habit of burning it at a higher rate than piston based engines. Mazda even extended the warranty on all RX-8’s to cover the components—\> [http://www.google.com/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=mazda+rx8+extended+warranty&spell=1](http://www.google.com/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=mazda+rx8+extended+warranty&spell=1) ---
**Author:** ![gruppe-b](https://avatars.discourse-cdn.com/v4/letter/g/bc8723/32.png) [@gruppe-b](https://community.cartalk.com/u/gruppe-b)\ **Post date:** [January 15, 2009, 4:06pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/7 "2009-01-15T16:06:06Z")
i’ve read that Rotary engines require regular(non-synthetic)oil of a specific formulation.if i were you,i’d use exactly what the owners manual suggests.i think it has something to do with the fragility of the engines sealing surfaces-the oil needs to have a certain mix of lubricants,additives in it to keep the engine happy.vw vortex has a very good technical section on motor oil(you don’t need to be a member to view it)i believe that is where i read about it. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [January 15, 2009, 5:14pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/8 "2009-01-15T17:14:23Z")
“citing Castrol as stating on their bottles that their version of 5W-20 should only be used in vehicles that make short trips” Have you seen that wording on a Castrol container? I know that I haven’t! Right now, I would put those articles (internet based, I assume) into the same category as those junk e-mails that claim the CEO of Procter & Gamble stated in an on-air interview that “all of our profits go to the The Church of Satan”. Anyone with a functioning brain realizes that the CEO of P&G never made any statement of this sort, and with that as an example of the type of tripe that is bandied about on the internet, I would suggest that you go to a store, and look at some Castrol bottles for yourself, rather than accepting that information at face value. ---
**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\ **Post date:** [January 15, 2009, 9:32pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/9 "2009-01-15T21:32:03Z")
``` I put a lot of miles on my RX7 and I used the recommended oil and weight. As I recall it was 10W30 then. Those engines are great. Mazda knows what they are doing. 200,000 miles is not old for a modern rotary engine that had the Mazda recommended maintenance performed. ``` ---
**Author:** ![rocketman](https://avatars.discourse-cdn.com/v4/letter/r/eada6e/32.png) [@rocketman](https://community.cartalk.com/u/rocketman)\ **Post date:** [January 16, 2009, 3:31am UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/10 "2009-01-16T03:31:46Z")
I have an RX-8 . . Mazda just extended the engine warranty to 100,000 miles. Rocketman ---
**Author:** ![rocketman](https://avatars.discourse-cdn.com/v4/letter/r/eada6e/32.png) [@rocketman](https://community.cartalk.com/u/rocketman)\ **Post date:** [January 16, 2009, 1:12pm UTC](https://community.cartalk.com/t/rx8-rotary-engine-failure/24952/11 "2009-01-16T13:12:46Z")
Mazda sent owners (well, I got it, anyway) . . . an extension to their original warranty and a video which addresses a few problem areas . . . one is type and weight of oil to use . . . they said to use regular (dino) 5W20 and to check the level every other fuel fill-up. Rocketman