Home Reliability Mazda RX8 Reliability: Is This Car Worth Your Money?

Mazda RX8 Reliability: Is This Car Worth Your Money?

by Kelvin Yates

Mazda has long been known as the brand that pushes the envelope, explores new boundaries. But few releases were as interesting as the Mazda RX8, and over the years, this car is more fascinating than it was during its launch in 2003. True rear-wheel drive, manual-gearbox, naturally-aspirated sports cars are infrequent in today’s market, even if you don’t count the innovative features like the RX8’s coupe-esque body style and Wankel rotary engine. Let’s talk about Mazda RX8 reliability.

At launch, the RX8 had to go up against cars like the Nissan 350Z and Honda S2000, while we also compared it to mechanically nifty rides like the Volkswagen Golf R32 and Subaru Impreza WRX.

Today the Mazda RX8 is an affordable find, and although buying secondhand models bears risks in contrast to many of its rivals, there are rewards too. If the fuel bills are something you can live with, the RX8 will give you entertaining and unique driving experiences. After all, there are few cars today that can influence the mind like a Mazda RX8.

The sound the rotary engine produces as it hits the 9,000 rpm mark runs a shiver down your down; not to mention how the car moves through corners. However, these emotions come with a trade-off. The RX8 is arguably one of the most unreliable vehicles money can buy. What affects the Mazda RX8 reliability?

Mazda RX8 Design

At the core of the Mazda RX’s design is its unique rotary engine. Termed the Renesis, this engine was a heavily enhanced variant of the 2-rotor 13B equipped in the RX-7, with exhaust ports newly placed on the side of the rotor housings instead of its periphery, along with new rotor seals – something the rotary design had struggled with for some time.

Dissimilar to the RX-7, the Renesis wasn’t turbocharged by rather naturally-aspirated, yet still able to produce 237bhp at 8500rpm. A 189bhp variant was available too. The latter was equipped with a 5-speed with various ratios whereas the former got a 6-speed manual transmission.

Underpinnings bore a close resemblance to the ones in 3rd gen Mazda MX-5 as engines used prototypes from that model to evolve the gearbox. Suspension is multi-link at the back and double-wishbone at the front, and Mazda kept the weight relatively less: 1300kg figure. In comparison, the less powerful and more conventional 1.8-liter Mazda 6 came in at 1345kg.

Mazda RX-8 Reliability

What Else Did They Do?

The interior wasn’t as great as some from other German alternatives but a uniquely-designed dashboard and low-slung driving placement gave the RX8 a special feeling – and it was practical by coupe standards too.

Multiple special editions were released during the production run of the problematic model, but the most interesting one would be the PZ. Prodrive developed it and the majority of the changes were made to improve the car’s handling. Therefore, power remained the same, but Bilstein dampers, OZ-racing wheels, and a pumped-up exhaust combined to form a more serious sports model.

More significant changes were brought about in 2008, with a facelift to represent the brand’s theme for that time (corporate), revised geometry, a high specification, chassis stiffening, and a brief final drive. Mazda announced that they were going to halt production of the RX8 in 2011 due to growing concerns about the emissions standards and the car’s poor sales.

What Engine Does A Mazda RX8 Have?

Our protagonist for today derives energy from a 1.3L Renesis two-rotor rotary engine. This engine generates 212 HP at 7,500 rpm alongside 159 lb.-ft. of torque at 5,500 rpm. Add a manual transmission to the mix and the Mazda RX8 rotary engine can climb to 232 HP at 8,500 rpm. Despite all the red flags, customers were always intrigued by Mazda’s RX-series’ rotary engine. There’s a reason for that.

Mazda RX-8 Reliability

This engine offers many advantages over a conventional piston engine. For instance, they offer high output with minimal displacement (the engine on the RX8 is only 1.3 liters but generates 232 HP), with fewer moving parts and a lighter frame. The engine’s small size and reduced weight allowed the engineers to enhance engine placement.

Moreover, when it comes to dynamics, not many cars have achieved the perfect balance between ride quality and handling precision – a trait acquired seamlessly by the RX8. But even though the rotary engine is quite impressive in output, the poor fuel efficiency is a problem. Not to mention how the torque only peaks high in range.

Mazda RX8 Reliability Issues

What makes the Mazda RX8 a car to stay away from? Weigh in these factors if you want to get this one:

Mazda RX8 Reliability: Engine Problems

Low Thermal Efficiency

The RX8’s Achilles heel lies under its hood. The worst bit is that it isn’t just a part of the engine, but rather the whole thing, since the Renesis 1.3-liter rotary engine is infamous for being an unreliable, gas-guzzling machine. Instead of pistons, rotors are used by this engine, and over time, they deteriorate.

In simpler words, the engine is too rev-happy and thus, the apex seals found on the corners of the rotors and work with the rotor housing degrades faster. You have to replace these seals if they wear out, which warrants an engine rebuild. But there are measures you can take to increase longevity.

The Wankel engine offers reduced thermal efficiency by its very design. Part of this can be owed to the low compression ratios – thanks to the poorly constructed combustion chamber.

Problems With Keeping The Engine Sealed

Inside the engine, gas in the chambers is not allowed to enter an incorrect chamber and/or cross-contaminate. The apex seal is meant to keep the gas in the right chamber but it may fail sometimes. Although combustion always happens on a side, a big temperature differential can happen and thus, cause issues. As the metal expands, the seal refuses to secure the gases.

Poor Fuel Efficiency

More often than not, you will have to inspect the fuel levels to ensure your car has an adequate amount of gas.

Terrible Emissions

This is unarguably the biggest issue with the rotary engine. You burn through a significant amount of fuel with this engine, while it can also be a challenge to secure different chambers of gases. And the thermal efficiency is low as well.

Longevity Of RX8 Engine

There are numerous speculations and answers regarding how long the average Renesis rotary engine will last. Similar to any other engine, proper maintenance and care will extend its service life. However, that can also mean 80,000 miles and under. Sadly, if you aren’t aware of what you are getting on early on, you will run into problems later.

This is why maintaining a routine maintenance procedure is essential – and not just for the RX8; any vehicle. Unless you can pay to rebuild an engine every two years, we suggest you do that. Keep in mind that the Mazda RX8 isn’t low-maintenance. It has a distinct “aesthetic” face value that comes with a lot of expenses later.

If you would rather not deal with that, go for a Mazda Miata or Honda S2000. Both of those are fine choices.

Mazda RX8 Reliability: Overheating Issues

Many owners of the Mazda RX8 complain about how this car has nasty overheating tendencies. If you drive for too long, you may start seeing a little smoke or steam coming out from under the hood of the car. Additionally, there are chances there may be smoke emitting from the engine temperature gauge’s needle.

Failure to supply coolant to the car consistently will result in leaks and a chance of the fan connection system exploding.

Mazda RX8 Reliability: Brake Issues

When the Mazda RX8 was fresh off the production lines, it boasted an incredible braking system. However, over time, owners started noticing how the car was just a bit noisier than its first hours. At one point, it got so loud that people would have to stop driving. Dirt and debris would accumulate easily on the brake drums and creaky noises would come from the brakes.

Mazda RX-8 Reliability

If you want to fix these conditions, try taking some brake parts cleaner and running through the dirty area. Moreover, you might need to adjust the brakes a little if you see them touching the drum when the wheels are moving.

Mazda RX8 Reliability: Ignition Difficulties

Ignition is a bit of a problem area for the RX8, along with the engine, of course. Drivers complained that it would take them too long to start the vehicle, and it wouldn’t even start at times. People assumed there was an issue with the car’s battery terminals or cable connections going to the battery.

Furthermore, there are general issues with the fluid level sensor found in the expansion tank. This car is a thirsty one, meaning it will require a lot of gas to operate smoothly. Owners got tired of constantly refilling the oil just enough for their cars to run.

If you have gone over all possible reasons your car may not be starting, make sure to double-check anything that you might have brushed over fast to check where the problem was.

Mazda RX8 Reliability: Transmission Issues

Second to the rotary engine, the Mazda RX8’s most problematic factor would be the transmission. Owners found that even after pressing down on the clutch pedal and trying to move the stick shift, the car transmission wouldn’t budge. Not the ideal scenario for any car owner! This is why many sports car drivers decided to ditch the RX8 models on their tracks.

In addition to this, the RX8 riders during a race had worrying complaints. They said that when they attempted to shift the vehicle from a stop position into first gear, the gears fixed in position, making it difficult for the driver to speed up.

The problem might be the RMS level the engine is at and trying to understand the acceptable way for the gearbox to shift. Also, you may have to tinker around quite a lot with the clutch linking and shift cables of this model as they do need some adjusting. For sports cars, in particular, it can be next to impossible to repair and adjust the settings each time they accelerate.

Mazda RX8 Reliability: Gear Issues

Cars aren’t designed to last forever. But, a car is meant to drive fine without causing any issues until the gearbox or transmission starts to wear down. The Mazda RX8 reliability is once again questioned due to its weak gear issue. In its case, slipping gears becomes a concern much faster. With any kind of vehicle, you have to check the transmission fluid (for more insight, check out our guide on when to check transmission fluid) and oil regularly. This is more applicable for the RX8.

Car problems transmission manual rotary engine

Drivers tend to get aggressive on the roads and encounter transmission fluid and oil burn at times from lack of fluid or high engine temperature. Bits of metal might also be moving around in the fluids and starting to wear down the transmission’s moving parts and the engine. If you are facing difficulties changing gears, make sure you have a look at these fluids first.

You might have to inspect your transmission, gearbox, and engine for problems. Make sure to inspect the fluids regularly. If the gears start slipping too easily, it’s time to get the clutch checked as well.

Mazda RX8 Reliability: Clutch Problems

Perhaps racers have nightmares of their cars struggling with a dragging clutch on the track. For example, if you are pressing entirely on the gas pedal to avoid a collision but the clutch does not fully engage into gear, your car will not have the required power to quickly move away from the opposing force.

Another example would be seeing the RPM increase before it should after the car has been put into gear. The clutch either doesn’t engage or drags. A clutch is said to be dragging when it fails to disengage from the flywheel and clutch disk when the driver presses the clutch pedal. As the driver tries to shift the gears, the car would refuse to shift to another gear since the clutch could not pull away from the flywheel in time.

The problem might be the cable connected to the clutch pedal coming loose. Tightening it should resolve the issue. If problems persist, bring your car to a mechanic. Any time your car shows difficulty in shifting gears or makes strange noises when doing so, it’s time to get a check-up. If you are shifting gears, keep an ear out for any sounds that might become a problem as they could be causing a little gearbox damage.

Mazda RX8 Reliability: Engine Light Issues

Engine light indicators are an essential element on the dashboard. They indicate issues that are happening within your car so you can repair them before major damages are caused. Some owners reported that their RX8 was displaying issues with these lights as the sensors would not work properly. However, the problem might also be caused by an aftermarket part, which was realized by an owner after diagnosis.

It would be difficult to confirm that the sensor is the problem without having the car checked by a certified professional. Owning an OBD-II scan tool is recommended for every car owner. You are spending some money now but you will find the benefits outweigh the cost. This diagnostic tool will effectively let you know about the components of your car that are showing erratic behavior. The hands-on approach is quite efficient.

Mazda RX8 Reliability: Engine Noise Problems

Many owners have also noted heating a slight buzzing or humming sound when driving an RX8. When a racer or driver changes gear, they may hear a clunking noise. While noises are normal from anything mechanical, we do recommend getting your car checked just in case. Some mechanics and auto repair shops offer free diagnoses if you vouch to let them repair your vehicle if something is wrong.

Before starting your RX8 again, you should for slippage, wire connections, seals, and anything out of the ordinary in the clutch cable. With an attentive ear and keen eyes, you can identify when you have to stop and decipher the reasons for clunking and humming noises.

For all our enthusiastic DIY-ers, you will be happy to know that many of your cars can be done by you with the help of a few simple tools and the perfect guide. Save yourself a few bucks and take the leap – you can surely repair a few small issues by yourself.

Minor Issues

Apart from the major problems mentioned above, the Mazda RX8 reliability is debated because it suffers from an array of small problems. Although not as irksome as engine or transmission problems, these minor defects sure can annoy an owner. “Quirks” to keep in mind include:

How To Resolve Mazda RX8 Reliability Concerns

Pre-Mixing The Fuel

As the engine of an RX8 is used to consume fuel voraciously, we recommend pre-mixing the fuel before putting it into the tank. All you have to do is add a little 2-stroke motor oil to the fuel tank during filling it up so the engine seals are lubricated better, resulting in reduced oil consumption. For the Mazda RX8, the recommended amount is 0.5 oz. oil for each gallon of gas. This technique is very popular so you can find multiple video tutorials online to help you get started.

Note: Remove the stock catalytic converter using a straight pipe before the process since the pre-mixed fuel could make it explode. As a result, the car would stop passing smog.

Replace Ignition Plugs And Coils

Another step to take in making the Mazda RX8 more reliable is to replace the ignition coils, plugs, and wires. This is a pretty simple process and a typical maintenance item in most cars, however, it’s more crucial if you’re planning to make the RX8 last longer.

Buy A Cooling Fan Control Kit

We mentioned before how the RX8 has this tendency to rev high. Naturally, it builds up the heat at an extended pace. Experts recommend that you replace the cooling hoses and radiator with aftermarket finds that flow a bit more freely, but a cooling fan control kit is a good choice too. This kit allows you to change the temperature of the cooling fan’s operation.

At stock setting, a cooling fan will turn on once the engine temperature reaches 206 degrees Fahrenheit. However, with this kit, when the engine temperature gets to 180 degrees, the fan turns on at high-speed mode.

Pros And Cons Of Mazda RX8


  • Although this car isn’t the fastest one you can get from the RX lineup, it has an undeniably amazing feel. Perhaps the only model that can compare is the RX-7.
  • Affordable. Since general buyers tend to underestimate the Renesis rotary engine, you can get used RX8 models for good prices (particularly true for the U.S.).
  • Very sleek and classic chassis. Mazda pays special attention to styling and it shows with the RX8. The styling isn’t aggressive but rather refined with its defined curves and smooth lines.
  • The latest technology is incorporated even in a model that is old. Includes dash-integrated sound system, proximity keys, and electric operations.
  • Great sound.


  • Poor gas mileage.
  • The interior is weirdly small. For taller drivers, they would find the top of their heads brushing up against the top of the cabin.
  • No payload. Despite the nice trunk, there’s simply not enough space in there for anything more than some groceries.
  • Due to its low-end torque, the car takes some time to take off. But the acceleration is smooth.
  • In comparison to other models from Mazda, the RX8 requires more maintenance. Plus, you don’t get the luxury of holding onto anything. One missed oil change could mess up the rotary engine, and you don’t need anything else harming the already temperamental component.
  • Emissions, insurance, and registration. As the RX8 has some emissions concerns, these documentations cost higher and will have you working on them every other year.
  • No AUX port on the radio.

Facts: Tips for Maintaining the Mazda RX8 Engine

  1. The Mazda RX8 has had a reputation for being an unreliable car, mainly due to issues with the Renesis engine, but it can be a reliable car if treated like a rotary engine.
  2. RX8 engines fail due to a variety of issues, including excessive carbon buildup, overheating, fuel starvation, catalytic converter failure, and clogged oil injection lines.
  3. To keep the ignition system alive and well, change ignition coils and spark plugs every 30,000 miles or sooner, or install aftermarket coils.
  4. Symptoms of ignition failure include power loss, drop in mileage, inconsistent idle, shaking at idle, unstable high rpm, misfiring, overheating catalytic converter, flooding, and inability to start.
  5. The cooling system components, including the radiator, thermostat, water pump, expansion bottle, and coolant lines, are sensitive and prone to failure, so regular coolant system flushes and maintenance are vital.
  6. Replacing the thermostat with a 172F thermostat can give the cooling system more headroom, and OEM replacement radiators are superior to many aftermarket options.
  7. Other reliability mods that can be considered include a BHR ignition kit, catless midpipe, silicone coolant lines, monitoring gauges, REMedy oil pressure kit, REMedy water pump and thermostat, COBB AccessPort, CSF3164 Radiator/Koyo V2695, SOHN adapter, fender liner slits, and premix.
  8. Regular maintenance such as keeping the oil topped up at all times and replacing all the necessary fluids, such as coolant, brake, transmission, and differential fluid, is essential.
  9. The sensitive nature of the rotary engine requires meticulous care to keep it running smoothly, which is why many enthusiasts lovingly bring one into their garages, only to let them go shortly after.
  10. Despite the challenges, owning an RX8 can be a fun and rewarding experience if properly maintained and treated like a rotary engine.

Mazda RX8 Reliability: Is Buying It Worth The Money?

Mazda RX8 started as the perfect buy for people who were searching for a stylish and cute family couple, with details like sleek bodywork and rear-hinged back doors. In the process, perhaps, the makers forgot about the silent killer they were put under the hood which affects the Mazda RX8 reliability. Suffice to say, a rotary engine isn’t everyone’s cup of tea.

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