2004 Mazda Mazda6 s 4dr Sports Sedan (3.0L 6cyl 5M)
I bought this car 2 months ago for $3000 at an auction with 196000km on it, or about 129k miles.
There oil kept disappearing quickly and I didn't know where it was going.
After about $2000 in repairs and getting some tires and rims, I find out that the cars' engine is through.
It was burning oil rapidly, the reason for that was the piston rings being worn out, and the reason for piston rings being worn out was the catalytic converter melting and blocking the exhaust creating excessive back pressure.
Not to mention the EGR valve recirulating exhaust gases as well as other particles into the engine which also screwed the engine over.
Very piss poor design by mazda.
the body design is beautiful, it looks better than 90% of the cars out there even though its 10 years old
poor engineering design, ford/mazda engineers should be fired over this.
Bought car with moderate mileage at low price (auction) and blame engineers not prior owner(s) maintenance habits? A poorly maintained car is going to behave as such.
The true warning is the fact that this was bought at a car auction. No test driving, no mechanical inspection, no maintenance records, no returns. That is why cars at car auctions are cheap. There is no guarantee.
Something caused the catalytic converter to go into meltdown, they don't do this on their own. It was getting unburned fuel (from a misfire most likely) into it. When it does it burns inside there and melts the substrate. The substrate usually breaks apart and clogs up the exhaust tighter than [non-permissible content removed]. When this happens to a vehicle, you will never see the back side of a stop sign. Top speed 20-30 mph with it constipated. You described a correctly functioning EGR Valve except for the "as well as other particles" part. That's what an EGR Valve does. Exhaust Gas Recirculation Valves or EGR Valves have been around for 40+ years. They lower combustion chamber temperatures to lower the formation of NOx emissions. Specifically, NO2 and N2O. NOx = NO2 and N2O Exhaust is tapped from an area well in front of the converter and the orifice on an EGR Valve is not large enough to allow something big enough to cause engine damage through it. Not the cars' fault it was neglected and driven with a misfire for too long.
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