Hi everyone I've had my rx8 for years now I take care of it and never have problems as of late I've had a few problems I don't know how to fix.

Problem 1, my check engine light is on when I got it checked initially it said vapor leak. I changed the gas cap and it went away for a bit then came back. When I got the car serviced the guy checked the light and it said it was from the catalytic converter. Do I need a new one or a sensor?
Problem 2, my coolant tanks radiator coolant has been bubbling and after running the car wren it's hot outside it spills some out the bottom. I had it checked for leaks they can't see any and after I stop my fan runs for a while! Help!

 

Post year, mileage, any modifications, and a brief service record of the car. That will get you the quickest and best answers.

 

It's 2004 107,000 miles and just stock.

 

So if the catalytic converter is original it is probably on its way out, if it isn't clogged already. You ever flush and change the coolant?

 

It could probably use a flush but doesn't explain the leaking out the bottom I assume the overflow

 

From your description, it sounds like you are boiling coolant, so flushing/changing coolant if it's old may help for now. Unless of course the coolant seals have gone bad and you are getting air in it.

 

For the cat, the easiest first step is to remove and examine it visually for clogging. If it is clogged or damaged, then you'll need a new one and you shouldn't drive until you have it. You'll also want to replace your ignition coils, wires and spark plugs since they are what leads to cat failure.

For the bubbling coolant, see if your radiator cap is holding pressure. There should be no hissing or bubbling from it when the car is fully warm and off. I had mine fail, not sure why. It's an easy first check. While you have the cap off, check for cracks on the plastic neck of the overflow bottle where the cap sits. It's a known failure point and a hairline crack there will prevent the system from holding pressure thus boiling early.

 

If your cap and cooling system passes the pressure test, then you likely have a thermostat and/or radiator partial failure, I would recommend replacing them together anyway, and they are cheap from Mazmart.

 

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.