Coolant leaking?
 

2007 rx8 - So a while ago my coolant light came on and I filled it with coolant and took it somewhere to check for a leak. They found no leaks. But when I turn my Rx8 on I can hear a sort of sloshing liquid sound coming from behind my console. The light never came back on. That was probably a month or two ago. This week my check engine light came on. The code says something is wrong with the catalytic converter.

I was googling and I am thinking that coolant has leaked somehow and coated the cat.
It cant be a head gasket leak so how would this leak occur? And would be it be reasonably fixable?

Re: Coolant leaking?
 

How many miles are on the 8?

Google "coolant bottle sensor RX8", you will get a lot of post saying how the sensor is bad. Unfortunately, you have to replace the whole bottle since its integral part of the bottle. This could be the issue if you are not losing coolant. If you are, your right, it cant be the head gasket, rotary's do not have one. It is possible you could have a housing seal leaking, but you will notice loss of coolant and possible smoke when driving.


Cats go bad from too much unburnt fuel, high temps, oil being burnt, etc. When I worked in a shop I had a lot cars come in say the cat is bad. Most ended up being the O2 sensor not reading correctly because it was coated in soot or just age, but it was still reading. So the ECU thought it was the cat being bad. If you haven't changed your O2 sensor, try that first. If you have had worse MPG's, that could be your issue. But letting it run with a bad O2 sensor, causes more fuel in the combustion, which then could cause the cat to go bad.

If you are losing coolant on a regular basis, check the cap for the coolant bottle first, especially if it not a lot of coolant.

Re: Coolant leaking?
 

Hello thank you for your reply! It was very informative. I took it to a place and they are saying it is my front O2 sensor that needs to be replaced. They recommended me going through Mazda dealership to purchase it, however I'm sure that will take a while and be much pricier than buying it through autozone or online. Is the front O2 sensor the upstream sensor? I see a lot of downstream sensors online but less upstream, and even less saying "front sensor". I just want to make sure I am purchasing the right part. And if I need to go OEM or purchase an off brand? I'm not seeing much on amazon, which is where I bought my replacement spark plugs and coils in the past...

Thanks for any additional advice you may have to offer!

Re: Coolant leaking?
 

I would agree with them on going through the dealer to get O2 sensors. The ones at the auto parts store are not to the same quality as directly from Mazda. You can try the parts store, some have had luck with them, but most have not. You can always check out rockauto.com, usually they are cheaper than parts store, just take a few days to ship. Check the dealer, it may surprise you on the cost. Some have for me. You can also look online for other dealers which some are cheaper including the shipping.

Yes, front sensor is up stream sensor.

Re: Coolant leaking?
 

Yes the one I was looking at through autozone was:
https://www.autozone.com/engine-mana...=&model=&year=

But I will give the Mazda dealership a call as well and see their prices. Thanks for your help!

Re: Coolant leaking?
 

It looks like RockAuto has it for even cheaper - same part number as the autozone.

NTK 25673 Oxygen (O2) Sensor | RockAuto