RX-8 VITAL CHECKS
MAZDA IS a company renowned for taking risks, and over the years itís produced some brilliant cars that nobody else would have dared to make. The RX-8 is a case in point, with its ĎRenesisí rotary engine, rear-hinged ĎFreestyleí back doors and rear-wheel drive. That rotary engine allowed Mazda to create a car much sleeker than more conventional rivals, although itís not the most frugal powerplant and you have to explore the redline to make progress, as itís not over-endowed with torque at low revs. But if you want something interesting and great to drive that you can use every day, then look no further.
í03 TO í10 updated models from about $15K
All RX-8s are four-door coupes with a rotary engine tied to a four-speed auto (141kW) or six-speed manual (170kW). Just like the 25-run, Bathurst 12 Hour-winning RX-7 SP (and the turbocharged MX-5 SP), Mazda Australiaís skunkworks motorsport division (led by Allan Horsley) created its own limited-run SP version. It was a project aimed at tarmac rally events such as Targa Tasmania and was largely developed without the approval from HQ in Hiroshima.
Said to develop in the region of 220kW with a Garrett turbo running only 6psi of boost, the 13B also ran a PWR intercooler, a custom intake and a 2.75-inch exhaust. Few were made.
There were various other global special editions over the years, such as the Kuro, Evolve and Nemesis, which can be worth a small premium over a standard car because of their unique colour schemes.
BODYWORK Widespread corrosion shouldnít be a serious issue, although some localised areas can rust badly. The sills are the biggest problem areas (they rot from inside out) along with the rear wheelarches and around the central brake light. More problematic are the plastic bumpers, which crack if the car is nudged; check for poorly repaired damage.
The bonnet and rear doors are aluminium, which donít cause any electrolytic corrosion problems, but the softer metal dents easily while paint adhesion (or lack of) can be an issue. On special editions with rare colours, check thereís been no repainting as colour matching can be fiendishly difficult.
Crash damage is a strong possibility, so check the boot floor and inner front guards for rippling. The shut lines should be tight and even; if theyíre not, itís likely that the car doesnít wear all of its original panels.
Its relatively modest power outputs are countered by a brilliant driving experience. With near 50:50 weight distribution, wonderful steering, strong brakes and good grip, the RX-8 is memorable.
The Ďwhat the?í factor is high with the RX-8... especially with those who arenít car people. Itís a four-door coupe, but its rotary engine is the true point of difference here.
Those rear doors arenít just for show. Despite having to open the front door first to release the rear, they aid access to the rear seats - which can accommodate adults.
OILY BITS All RX-8s have the same 1308cc twin-chamber rotary engine in 158kW or 170kW form. The higher-output modelís extra power is largely thanks to a redesigned intake system, although a slightly different ECU set-up also allows it to rev to 9000rpm compared with the 7500rpm of the 158kW (auto) version. Codenamed Renesis, the Wankel engine is designed to use 0.25 litres of oil every 1600km. More oil is used when the engine is under load, so at a track the consumption will be higher. Youíre supposed to check the dipstick on every other fill-up of fuel - but as the capacity between minimum and maximum is 1.5 litres, you wonít always need to top up.
Officially the sump should be filled with Mazdaís semi-synthetic 5W30 Dexelia lubricant, but most specialists recommend a 10W40 for better oil pressure as main bearings have been known to wear out otherwise. Fully synthetic oils donít burn properly, leading to carbon deposits.
Cars built up to the end of 2004 could suffer from the engine flooding if switched on and then off again quickly, due to the way the ECU was set up to get the engine quickly up to temperature. This led to cars failing to start, and Mazda issued a recall to fix it; check that the work has been done. Some cars still flood, but hotter spark plugs help. Whatís more likely to be a problem is a tired ignition system. There are four coil packs which should be replaced every 50,000km or so. If theyíre not renewed, the subsequent misfiring will lead to the engine seals deteriorating and compression loss. A genuine coil pack has the part number embossed in the plastic, but there are convincing fakes around; the suffix should end with a C. The original (flawed) designs have an A or B suffix; sub-standard pattern or counterfeit coil packs are common.
While itís not quite the rally-bred Evo slayer we expected, the 190kW all-paw turbo Mazda6 MPS is a decent road car. Plus, itís something out of the ordinary with its boosted four-pot and topmounted intercooler. Itís manual, too.
While not an obvious performance option, with a 228kW/375Nm 3.5-litre V6, the IS350 is an intriguing choice. The naturally aspirated six sounds good and power is sent to the rear. Itís only available with a six-speed automatic.
With the boosted 3.0-litre N54 inline six churning out 225kW/400Nm, the 335i offer lots of bang for your bucks - and thereís plenty to choose from second hand. The other added bonus is it comes in sedan, convertible and wagon body styles.
Poor compression isnít unusual; specialists can check with a meter. However, a cheap and easy way of diagnosing a wrecked engine is to try to start it when hot, but this can be masked with an uprated starter motor. Good used engines are scarce, but not especially costly when they do turn up; donít buy without doing a compression test.
Thereís a float inside the coolant expansion tank which sinks, illuminating a warning light on the dash; disconnecting the sensor wonít affect the ECU and itís easy enough to check the level manually. The oil-filled rubber engine mounts fail, especially on the offside due to the exhaust manifoldís proximity; the rubber breaks up, leading to crunchy gearchanges as the engine drops. Genuine mounts are available, but aftermarket polyurethane-filled items last longer; a DIY swap is possible.
Inside the front bumper are twin oil coolers along with a heat exchanger for the air-con; these get hit by stones, leading to damaged fins. This damage is just cosmetic, but the oil cooler pipes corrode and split, especially on the nearside. There are three steel pipes (engine to cooler, cooler to cooler, cooler to engine); the first is usually the problem. You can buy a stainless steel replacement fairly cheaply.
The five- or six-speed manual gearboxes are very strong, but some GL5 oils can cause problems with the baulk rings of a six-speed box, so see if the service history shows GL4 having been used. GL5 is fine for the five-speed transmission though. The MX-5 unit fitted to the 2008-on R3 can suffer from tired synchro rings on fifth and sixth gear. Feel for crunching into fifth and sixth; if itís evident, budget for a rebuilt gearbox or you can pick up a decent used unit.
Mazda replaced quite a few clutches on early cars due to premature wear, but wear can be an issue even now, especially on hard-driven cars. A clutch can last for 130,000km, however any sort of track use can cut this by two-thirds, so feel for slipping under acceleration.
When the RX-8 was facelifted in July 2008, it was given a lower-ratio diff (4.777:1 instead of 4.444:1) to improve acceleration, and the six-speed manual gearbox got a taller top gear ratio to maintain lower fuel consumption.
The catalytic converters hang down, potentially leading to them getting bashed. Itís worth tapping the back boxes and listening out for rattling sounds that signify disintegration. If theyíve done so the car will feel less responsive under acceleration and will be hesitant to rev fully. Blocked cats are common and itís worth paying for a new cat thatíll last.
The sliding pins in the brake calipers can seize up so the carrier has to be refurbished.
TRIM AND ELECTRICS The interior tends to last well, but the front seat bolsters wear with high mileage and the front seats get bashed by people getting in and out of the back. Check the outer edges of each front seat for wear from the seatbelt anchored on the rear doors.
The catalytic converter sits under the front left mounting for the driverís seat - it can run hot and roast the carpet. Alloy wheels were fitted to all RX-8s.
All RX-8s came with climate control which needs to be re-gassed occasionally. Electrically adjustable and heated seats are fairly common, so check all of the functions work - missing controls are common. Lower-spec RX-8s came with halogen lights, while higher grades got xenons that also came with washers and self-levelling. The self-levelling can fail, which means a replacement sensor is required. The electric power steering should feel light, so if it doesnít, vented coolant may have fouled the electrical connectors under the vent tube or the steering UJ on the rack may need regreasing to free it up.
While the list of cons looks extensive, the pros of owning a rotary (and its uniqueness) canít be forgotten.