Mazda iridium plugs

my girlfriend has a 2004 Mazda Rx8 (edited) with 65k miles on it and had the plugs and coils changed then a month later the car won’t start. After two months the shop figures out the plugs are bad - apparently she’s supposed to redline it when driving to keep from having carbon build up, which is what caused the new plugs to go bad. She was told iridium plugs cannot be cleaned and had to be replaced even though they had less than 200 miles on them.
She was charged $500 for changing the plugs and a compression test. This sounds bogus to me but she’s happy she didn’t have to have the engine rebuilt, which is what they originally said was needed.
Does this sound legit?

Sounds bogus to me. I’ve never heard a requirement that red-lining the engine is necessary for any car. If the plug tips were coated with gunk or burned beyond recognition after only 200 miles, and the car hasn’t been mistreated, you’re going to have to figure out why. Common causes would be too rich or too lean mixture, oil fouling, or coolant getting into the combustion chamber. Mixture problems are usually posted in the computer’s diagnostic trouble code history. Has that list been read out of ECM memory yet? If not , that’s where I’d start. Also, were all the plugs affected or just a subset?

If carbon is building up that quick, it is running WAY rich, and that needs to be addressed.

If the plugs were killed in a few hundred miles there’s an issue which killed them.

The redlining the engine bit to keep the plugs from fouling is utter BS. If the plugs are oil fouled there’s an engine problem. If the plugs are badly sooted there’s a fuel/air mix problem due to carburetion, etc.

What is the model year of this Mazda Rx3?

Is this a '70s rotary-powered car? Good luck keeping it on the road.

Five hundred bucks for a compression test and a set of overkill Iridium plugs. Wow.

If it really is an RX-3 (1971-1978) it does NOT take iridium spark plugs. Hope you have a good Mazda-specific mechanic for this ‘antique’ rotary.

Your GF is getting screwed and the redline suggestion is pure unadulterated bull.
My guess is that they didn’t have the correct plugs in stock so they stuck a “colder” plug in. However, whatever the true cause ends up being, I strongly recommend that she try a different shop.

And now, my second suspicion…
We’re getting this information third hand and incomplete. It’s entirely possible that as well-meaning as you might be what actually transpired is very different from what we’re reading. It would be a great help if your GF could join the thread so we can ask her some questions, like was there an operating problem before the plugs and coils were changed, if so what was it, how many miles the car has, and a few more questions.

There’s an old and commonly used illustration of how stories change as they travel from one person to another. One person in a small group privately reads a joke off of a piece of paper to a second person. The original written joke stays with the first person. The second person tells the joke to a third person in private, the third to the fourth, etc. The last person in the chain tells the joke out loud to the group. At that point the joke rarely even resembles the original. It’s human nature.

Here’s my guess - it’s a 1990s MX-3, with either the 4 or V6. NONE of them are listed as using iridium plugs, either.

I believe its an 09 or 2010. She was told by different people that she needs to get the rpm’s up high occasionally to keep from building up carbon - I may have mispoke when I used the term “redline”. They gave her the old plugs - she didn’t want me going in to talk to them because I was pissed and already in a bad mood and I knew I’d end up yelling at them. I’ll post a pic of the “old” plug as soon as I’m able - there is buildup on it and I thought it was really odd that it happened so quickly so the comment about it running too rich makes a lot of sense.

I’ll ask her about the diagnostics - but if it took the shop two months just to figure out the plugs were bad I doubt they even know what the word diagnosis means!

I’m sorry - it’s a 2004 RX8 with 65k on it.
The comment about the joke being passed from person to person was spot on!

Since this apparently an MX instead of an RX this means fuel injection. If the plugs were sooted up badly then the fuel/air mixture is too rich. A number of things can cause this but being that bad I would check the fuel pressure regulator first for a ruptured diaphragm. Remove the vacuum line and note if there is any gasoline in it.

Another possibility could be a clogged catalytic converter which is easily checked with a vacuum gauge.
As quickly as this is happening it has to be something obvious.

It’s an Rx8. Here’s a pic of the bad plug. Thank you very much for the replies - next time I’ll check here first!!
Trouble posting pic… I need a drink.

Successful finally

Unfortunately, this vehicle uses a rotary engine (2 rotor) not a conventional reciprocating engine. Rotary engines were a fantastic concept, because they used spinning rotors with seals at the apexes rather than pistons. They did have an inherent weakness, however… when the apex seals begin to wear, they burn oil, often prodigiously. It is also pretty much impossible to successfully rebuild a Wenkle rotary engine.

I’ve attached a link to illustrations of how the rotary engine works.

I don’t know of any way to compensate for worn apex seals. This engine is a very unique engine, used only in this car, and you might get more help on an RX8 forum. Perhaps there’s a higher heat range plug that can be used, or some other trick that RX8 afficiados know. These are “niche” cars, and have very specific requirements and weaknesses.

I truly wish I could be more help, but the engine truly is unconventional. It’ll take someone who has worked extensively with these engines, and an RX8 website would be the best place to find them. Why the mechanic didn’t explain to her up front that these engines are unique and refer her to a specialist is beyond me (or did he?).

I truly wish you the best with this.

Those plugs look kind of sooted up for only a few hundred miles but I can’t tell from the pics if it’s baked oil or a rich mixture.

Has the Check Engine Light been on and/or flashing?
Has any kind of diagnostic code or codes shown up?
Was it running at lease decent before the no-start and was the car towed to them?
Did they happen to provide any compression numbers? Those should always be written down.

Just to clarify one thing. Are you saying these guys had the car for 2 months after the no-start before they came to the conclusion the new plugs were bad?

Please excuse the questions but they are relevant.

Yes, they had it for two months before concluding the issue was bad plugs. The car was fine after the plugs were changed and the car sat a few weeks due to the weather then it started once and then wouldn’t even make any noise when trying to start - it just wouldn’t do anything at all.
I’m going to take the plug to my mechanic and ask what he thinks - I just wiped it with a paper towel and a lot of the gunk wiped of but there’s still some that feels naked on.
There were no lights flashing and the diagnostics were not run but we have an auto parts store that will run them for free so I’ll try that, too.

I will check with a specific RX8 forum - good suggestions- thank you very much guys!

Does not making any noise at all while trying to start mean that the engine is not being turned over by the starter motor or that it is turning over but simply won’t run?
The former could point to a weak battery, poor cable connection, or the possibility of a bad neutral safety switch which controls the starter motor operation.

I can’t say much for a shop that has a car for 2 months before coming to a spark plug conclusion while running no diagnostics.

Without seeing the gunk on the plugs personally I can’t tell if it’s oil or excess gas. If the latter I would check the fuel pressure regulator as that only takes a minute.