RoddyMac

I have had so many conflicting opinions on general maintenance for the RX8 thought I would post this to hopefully dispel any confusion..

1. I was told to get a compression check on my engine to show its condition and flag any issues. When at the Mazda garage they said they would do a Hot and Cold compression check and charge me for both, afterwards I was told I only needed the hot compression test and Mazda are pulling a fast one making me pay for both?

2. When using Petrol always use premium fuel (more expensive) yet at a local garage I met an RX 8 owner who said hed always used normal unleaded no problem?

3. Keep oil topped up as the Renesis rotary engine uses oil as part of the combustion process, when topping up use RX8 Mineral oil not semi or synthetic? yet I have met several people who use semi synthetic and a local garage put rx8 into computer and he fetched me semi synthetic oil..I currently use mineral oil Mazda bought but wondered is this a farce and can I use semi synthetic as apparently the car is designed to deal with it?

hope i can get some clarity 8)

Gravey

iTrader: (3)

1. Yes just hot test is required.

2. It is recommended to use premium, you will find arguments on that topic here with the majority leaning towards premium use.

3. The oil isn't used as part of combustion, it is used to keep the seals lubricated. Nonetheless it is consumed so you should always keep an eye on the level.

RIWWP

iTrader: (2)

1) Yes, the dealer instructions state that the engine needs to be hot, a cold compression test is entirely pointless.

2) Yes, some RX-8s can get away with regular fuel because their engines are failing and thus have low compression. High grade is mandatory if your engine is healthy, since high compression is what is working against the octane grade. Higher compression = more compression heat. Octane increases the detonation temp of the gasoline to compensate for higher compression engines. If an RX-8's engine is failing evenly, then lower octane gasoline can be used safely. So yes, it's possible, but it only means that you have bigger problems.

3) Top up with the same oil that you use during regular oil changes. You can mix oils, but there isn't a reason to explicitly try to mix them. Pick a good oil to do changes with, and then keep using the good oil for topping off. No reason to go inferior. Synthetic vs semi-synthetic vs mineral ... it's all a pointless arguement. All consumer oils are synthetic. All of them. The labels are almost entirely marketing labels. The only real difference between them is that oils labeled 'synthetic' hold their viscosity longer than oils not labeled 'synthetics'. The 'non synthetic' oils in the RX-8 can have lost all of their viscosity additives within 2,500 miles. The 'synthetic' oils can hold up to around 3,500 or so, depending on the oil. Mobile 1 0w40 is the oil that has consistently scored the best in used oil analysis testing in RX-8s from owners here on the forum. There is a big thread where people contribute their results, so it isn't some marketing somewhere or applying to some other car.

RoddyMac

Many thanks for advice given. I think were clear on Hot compression test only and best to use premium fuel unless your getting low compression. Regarding oil Mazda gave me ultra 5x30 mineral oil and the garage gave me 5w30 semi synthetic. I take from the posts both are safe but look into mobile 1 0w40 for better results. keep filling up the oil.

RoddyMac

Ahh sorry forgot to mention, it seems common practice to try and get to 6,000 revs at least once a journey, apparently this helps rid the engine of carbon particles that can damage the engine and seals? also I have been told at 6k revs or above secondary ports are opened keeping them oiled and in good working condition?
Any truth to these statements?

BigCajun

iTrader: (1)

Drive it like you stole it.

RIWWP

iTrader: (2)

Yes. Lugging the engine everywhere and not getting the RPMs up higher at full throttle will eventually kill an engine from carbon choking it to death. High RPM full throttle does not 'eliminate' carbon, but it helps keep the buildup down at more reasonable levels.

gwilliams6

RX8 Club’s recommended maintenance schedule, more comprehensive and proactive than Mazda's schedule.

30,000 miles:
- Replace Ignition coils
- Replace Plug wires
- Replace Spark plugs
- Clean MAF (mass air flow sensor)
- Clean ESS (e-shaft sensor)
- Reset ESS profile
- Clean power steering connections
- Clean battery terminals and clamps
- Replace transmission fluid
- Replace coolant (Mazda FL-22 is highly recommended)
- Replace air filter
- Replace brake fluid (fluid in the brake lines AND the clutch line)
~$300 USD in parts if you shop smartly.


every 60,000:
...all 30,000, plus...
- Clean all chassis electrical grounding points
- Replace accessory belts
- Clean OMP lines
- Replace rear differential fluid
- Replace thermostat
- Clean / Straighten AC condenser fins
- Clean / Straighten oil cooler fins
- Inspect catalytic converter
- Clean / Inspect intake valving
- Consider / inspect all points in 90,000+ as well, many items fail early
~$130 USD in parts if you shop smartly.

90,000:
...all 30,000, plus any 60,000 not yet done, plus...
- Replace coolant bottle
- Replace radiator hoses
- Replace radiator
- Replace front O2 sensor
- Replace motor mounts
- Inspect clutch pedal assembly for flex / weld breaks
~$900 USD in parts if you shop smartly.
At 100k, anything original in the cooling system is really suspect and failure prone. It represents the biggest threat to your engine.

RoddyMac

Yep made a copy of last post for its next service!