Credov's researched list of the 6 faults the Mazda RX8 is known for (2005–2012), 6 of them serious or costly. Each one says what to look for when you check the car, so you can spot it before you buy. Not every car has these faults: they are the ones worth checking on this model.
What to look for: Ask for a recent hot rotary compression test printout; without one, price the car as needing a rebuild.
Why it matters: A normal piston-engine compression gauge cannot read this engine properly, so without a proper hot rotary compression test you have no real way to know how much life is left, and the only fix once compression is low is a full rebuild or replacement engine.
What to look for: After the full test drive, switch off, wait 10-15 minutes, then restart and check it fires within a second or two.
Why it matters: A poor hot restart on a car with good ignition and a healthy battery usually means the rotary engine is near the end of its life, so this simple wait-and-restart test is one of the most telling checks you can do on an RX-8 before buying.
What to look for: Ask when the coils were last replaced, check for cracks on the coil bodies, and feel for a stumble under hard acceleration.
Why it matters: Worn coils do real damage beyond themselves: the unburnt fuel they let through overheats the catalytic converter and washes oil off the rotor housing seals, so an overdue coil set is worth more than its own price in avoided damage elsewhere.
What to look for: Test drive hot and check it pulls cleanly past 4,000 rpm; listen for a metallic rattle under the car at idle.
Why it matters: A clogged or broken cat pushes hot gas back into the engine, which is blamed for further rotor seal damage, so a sluggish feel above 4,000 rpm or a rattle under the car is worth investigating, along with whatever ignition fault caused it, before buying.
What to look for: Pull the dipstick on level ground, warm, and check the oil is near the top mark and clean amber-brown.
Why it matters: An owner who says the car never needs oil may simply never check it, and an engine run low on oil on this model is quickly destroyed, so confirming the owner actually tops up and checking the dipstick yourself matters more here than on almost any other car.
What to look for: Open both doors each side and look at the sill and B-pillar area with a torch for bubbling or holes.
Why it matters: Rust is now a bigger threat to RX-8 values than the engine, and UK specialists say it is cheaper to rebuild the engine than to fix rust that has gone too far, so a careful torch check of the sills and arches is essential before buying.
Got a question about a Mazda RX8? Ask Credov: a noise, a warning light, a part or how to fix it.
On top of the faults above, every Credov inspection covers the basics: fuel smell, leaks or filler rust, engine oil leaks, power steering fluid leak, drive belt cracks or squeal, rust underneath: chassis and mounts, engine mounts, engine oil level and colour, coolant level, colour and leaks, head gasket failure signs, cold start: rattle, knock or smoke, rough or hunting idle, engine running hot on gauge, gearbox or diff oil leak, swapped gearbox without lvv and more.
Researched by Credov from manufacturer recalls and service bulletins, owner reports and workshop sources. Repair prices are typical ranges, not quotes. See also fault codes and repair costs.