Originally Posted by 9krpmrx8

My extended warranty was through USAA, the name of the warranty company was Federal Warranty I believe.

Originally Posted by pistonhater

I was one who said it .....but i said in the context of so many arguments being made that oil weight (meaning, the use of 5W-20) is what kills these engines.

From what I gather, the bulk of the evidence seems to indicate that low compression and coolant leaks are the primary reasons for short engine life.

But you are correct about the bearing issue. I've have reviewed the information about abnormal bearing wear in the renesis (and consulted with a couple of engine builders on this matter recently to confirm), and it seems like there's a correlation between that issue and the use of 5w-20.

The question remains: at what point would the "abnormal bearing wear" cause the engine to fail - provided that it had good compression all along? 10K? 50K 100K? I've been told that engine failures due to bearing wear/failure are mostly seen in highly boosted/high performance race engines.

In other words, have these engines been failing (and replaced under warranty) because of abnormal bearing wear?

I'm really trying to understand this issue better.

Originally Posted by pistonhater

How ironic. And other people like the OP went without changing the oil and got more miles than you in 4 engines combined!! I guess you never know.

BTW, was that a Mazda warranty?

Originally Posted by nycgps

Engine bearing, just like anything else in the engine, decides how the engine "rolls" inside the engine. we're talking about differences in thousands of an inch. might not seem like a lot, but from 0.015" to 0.020" could means a fail in some case.

While I agreed that most failure came from failed coolant seal or broken Apex, that's why aftermarket Viton seals exist (vs stock teflon/rubber/teflon type of seal) but bearing good/bad does affect engine life. Usually Rotor Bearing/Stationary Gear Bearing is reusable in the engines, even if it has over 100K on it. the key is you have to use the right oil.

The last guy who build my FC's engine got it all wrong, wrong type of springs, wrong clearance, and wrong way to install some things. explains why the engine leaks like a **** with just 30K on it (if what the last owner said was true) so clearance does play a big role in modern engines.

Originally Posted by nycgps

Engine bearing, just like anything else in the engine, decides how the engine "rolls" inside the engine. we're talking about differences in thousands of an inch. might not seem like a lot, but from 0.015" to 0.020" could means a fail in some case.

While I agreed that most failure came from failed coolant seal or broken Apex, that's why aftermarket Viton seals exist (vs stock teflon/rubber/teflon type of seal) but bearing good/bad does affect engine life. Usually Rotor Bearing/Stationary Gear Bearing is reusable in the engines, even if it has over 100K on it. the key is you have to use the right oil.

The last guy who build my FC's engine got it all wrong, wrong type of springs, wrong clearance, and wrong way to install some things. explains why the engine leaks like a **** with just 30K on it (if what the last owner said was true) so clearance does play a big role in modern engines.

Originally Posted by pistonhater

Thanks a lot for explaining that. It really helps me understand this issue better. So it seems like rebuilding a renesis might also require replacing bearings and stationary gears - provided 5w-20 was used in it. Whereas other engines with different oil weight might be able to reuse those parts as you described.

Originally Posted by pistonhater

This whole issue puts us owners in a bind. I still have warranty left on my car, and would consider using a different oil weight, yet I assume Mazda would give me hell in case of a warranty claim. I'm somewhat familiar with the Magnuson-Moss law, but I can imagine how messy and frustrating it would by trying to enforce that law in case of a denied warranty claim (having a lawyer involved, down time with the car, etc. )

Originally Posted by nycgps

Most dealership just put 5w30, so I would have to assume most of them are ok with 5w30 as well. ...

Originally Posted by jsight

Exactly right... the dealer here seems to use 5w30. I don't think I've ever heard of anyone having a warranty problem that had regular changes with 5w30, but obviously there could be some dealer somewhere that might complain.

Originally Posted by Squidward

Mazda has produced an incredible car, despite its ****-poor gas mileage and terrible customer service and deceptive warranty.

Would I buy another one had they kept producing them? Absolutely!

Originally Posted by HiFlite999

If you're doing your own oil changes and faithfully documenting them, a friendly clerk at your AutoParts store may just mistakenly issue a receipt for 5W-20 when you bought 5W-30.