Ok so I'm new here but I've been browsing the site for a while before actually registering. I'm buying an 04 RX-8 tomorrow for a really good price. Its on its second engine, because it had an intake manifold issue. I had the VIN run and its been regularly maintained at a Mazda dealership, and its been adult owned. It recently had spark plugs, wires, and coils done. The owner used the standard 5w-20 in it.

We both live in New England, and it gets hot and muggy here until around September. I'll be driving the car a little harder and as my daily. I was wondering if I should be running something heavier like a 10W-30. I'll obviously be putting premium in it also. I dont know if it matters but its a manual. I appreciate your time guys and any response I get will be great.

 

The reason for the prior engine failure wasn't an intake manifold, that I can assure you.

Have you read the new owner's thread yet?

 

I have actually. I'm only going by what the dealer and the owner are telling me. They told the guy that since they have to remove the engine, he might as well buy a new one since the labor is the same. So he did, and they dropped it in.

 

Ah, ok. Your first post says that the intake manifold is the cause of the engine failure.


Well, if you read the thread, then you have your oil answer. I could re-type it, but...

 

I'll give it another look. I've read so much in the past 24/48 hours that I don't remember where half of anything is. Thanks for the heads up. Appreciate it.

 

I was thinking that 10w-40 would be best since the bearings are the same as the rx-7. I'm curious though why you think it wasn't the intake manifold though.

 

There are plenty of ways that this engine fails. "The intake manifold" isn't one of them. I mean, it's a tube (essentially). Literally shattering and ingesting parts of the manifold is probably the only way it could possibly cause an engine failure, and even that is a huge stretch. The only way they break is with improper nitrous use pretty much, and even then they just split along a seam.

Flood Mazda is your local dealer right? If they are the one telling you this, I wouldn't be surprised. I'd be very wary of anything they tell you (or the prior owner) anyway. I met another 8 owner that had an engine failure diagnosed by that dealer, and they told him that the engine was going to be $10,000, and another $6,000 for labor to install it. It wasn't until after he refused that they "remembered" that he had a warranty. Even if he didn't, that is simple scamming, since their list price for an engine is $2,001, and labor is usually around $1,000.

(Yeah, I lived in RI for 6 years)

 

Flood Mazda is one of the dealers around where I live, but I'd be mostly dealing with Tasca Mazda honestly. The car was bought out of state at Alden Mazda, so I was going by their information since they were servicing the car. They stated it was well taken care of.

 

Gotcha. I only had my 8 at Tasca twice, once for warranty replacement of my heater control ****, once for a compression test. I found their parts prices to have a higher than normal markup. Largely the reason I started learning how to do everything myself.

I ended up bringing my 8 to Liberty Mazda in Wakefield MA (north of Boston) for anything I couldn't do myself. The 90 minute drive was totally worth it. Great dealer.

 

Yeah dealer's tend to be higher in RI I've noticed. I used to work for a few dealerships. Two in florida actually and not only was the mentality towards the customer completely different there, the pricing range was much different also. I've driven many a high end European car and few high end Japanese cars, but this will be my first time owning an RX model. I got to drive an 09 RX-8 and loved it. I'm curious how much different they are.

 

The oil I use. 100% mineral, 15W40. Just FYI.

 

from the new owner thread
"Which oil to use
The most debated question in the community, bordering on a religious war, so I won't try to cover every point here.

It boils down to deciding for yourself.

Some go with 5w20, to stay with Mazda's recommendation in North America. Some go with 5w30 to go with Mazda's recommendation outside North America. Others go to 10w40 or even 20w50, the most common weights among RX-7s. The general arguement revolves around if 5w20 is too thin or not. Typically, you want to go with a heavier weight oil (higher numbers) the hotter the environment you live in. Many manuals outside of North America state something to this effect. So research up on it, and make your own decision."

I am running shell 5W-30 non synthetic, just plain ol'oil. Why you ask? Because I was walking through a Costco and picked it up at 2.86/L So I picked up 3 cases. Wanted 10-40 but 5-30, good enough. Can't beat that price either.

 

I recommend you put in 20w50 or 10w30 only because anything less will wipe out your bearings. Also I dont know if anyone has told you but I would also recommend premixing with every full tank of gas. I suggest Protek R developed by Pettit Racing it gets pricey but its better than a rebuild sooner than needed.

 

Just wondering. Can you just put a thicker oil in with the thinner oil?

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Short answer you shouldn't. Long answer you can.

You *can* it *shouldn't* be that bad as long as they are the same type and close in weight/viscosity (not synth with non synth) If you mix a 0W-30 with a 5W-30 you will have like a 3W-30... From a 0W-20 to a 10W-40 they may not mix well . I have had friends do it in their trucks in a pinch, but in a rotary - I am honestly not sure. Not something I would advise to do either.

Before I bought the shell oil I had to top up my car with 10W-30 synthetic oil which I picked up at a gas station, only used enough to get it to half way up the stick then went straight home (18kms). I was below the low line on oil (I don't know how that happened, I'm keeping a super close eye on my oil level every quarter tank of gas), then didn't drive the car until I changed the oil 3 days later, which was another 5 km trip to my buddy's shop down the road, but I did not run the car during that period at all.... Yeah, I'm spoiled, I get to use a car hoist, but also did other work on the car at that time lol otherwise I would have done it in my driveway.

Since rotary engines BURN oil, having oils that are a different type could effect how they burn off, and could possibly strain your pump (pocket of light oil to heavy). If you plan on driving the car more than around the block basically, to be safe, yeah change it. Better off spending the bit of money to prevent engine damage. Being cheap never turns out well nor does it save money in the long run. If you don't know how to change your own oil there are DIYs for that! Literally just involves taking the oil filter off, putting a new one on, jacking the car up, putting down a oil pan or jug, undoing one bolt, waiting 3 minutes, putting the bolt in, and fill with 4ish quarts of oil. Super easy, 15 minute job, or if your car is lowered like mine, as long as it takes you to find sufficient wood to raise the car up enough to get a jack under it +15 minutes (lmao).... or just wait till your next oil change and give the mechanic the oil you want to have put in the car.

 

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That helped a lot thanks. I don't have a problem changing my own, but but my local mazda dealer does ten dollar oil changes and they check a few things while theyre at it, so I usually just run downthere.

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