Mazda 3 and Mazda 6 Engine Failures

The Mazda 3 has three versions of four cylinder engines, two of which are shared with the Mazda 6 and displace 2.3L. Most (but not all) of APA's complaints concern the 2.3L 4 cylinder engines. We have received a small number of reports on the 2L engine, which is much more widely sold.

The 2.3L turbo engine is rare on the Mazda3 (likely less than 2% of production) and also shared with the CX-7, in which it equips all vehicles to 2009 and most in 2010. It has had several issues with the timing chain assembly, and turbo failures. Mazda has extended the warranty to cover repairs and made an internal change to the recommended oil (synthetic oil no longer recommended). Here is the list of warranty extensions:

2007-2009 CX-7 and 2007-2008 Mazdaspeed 3: oil consumption and smoke coming out of the tailpipe. PCV valve and routing changes, turbo repair covered if it has been damaged. 7 years/140,000 km.

2007-2010 CX-7: noisy engine, more noticeable on starting. Warranty on the turbo and timing chain extended to 7 years or 140,000 km.

The APA does not have specific info about warranty extensions for this engine on the Mazda6; we assume it's similar to above. The engine equips less than 2% of Mazda6 cars.

Non turbo 2.3L engine on Mazda 3 and 6: 2004-2007

The engine may begin to burn oil seemingly all of a sudden at 80,000 to 100,000 km. The consumer would likely be unaware of the condition unless they check the oil regularly. If the oil drops below 2 litres in the crankcase, intermittent oil starvation begins to occur, typically first at the location of the number 1 connecting rod -- by this time internal damage is severe. If the consumer does not stop driving the vehicle, the rod can fail completely and pierces a whole in the side of the block.

The cause appears to be gradual overheating of the engine, due to 1) an internal defect in the catalytic converter that can plug up over time OR 2) the catalytic convertor plugs up over time from burned oil in the exhaust stream. There may be other causes.

Failures appear more common with the manual transmission, perhaps because crankcase ventilation or some other factor is more affected by the overrun that accompanies gear changes. Used engines are in chronically short supply and expensive. In Montreal some recyclers have stopped selling the engines because they're too troublesome. APA has sourced rebuilt engines for about $3,500 in Montreal (plus installation). APA has recorded about 35 written complaints from consumers and confirmed a high rate of failures with rebuilders. We have not written Mazda directly about this issue, but could do so given the number of complaints.

APA can obtain a below retail price to replace the engine in Montreal, and likely a bit of break at our recommended engine specialist in Toronto. Either shop would be competent to report on the engine damage.

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