2006 Infiniti M35x
2006 Infiniti M35x; photo by Greg Wilson. Click image to enlarge

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By Chris Chase

You’d be excused for not knowing the Infiniti M sedan existed. It first appeared in Canada in 2003 and lasted little more than a year, and while the second-generation model introduced in 2006 fared better in the market than the original, Infiniti sold just 410 in Canada in 2008 and a measly 217 in 2009. Compare that to sales of its smaller G37, of which Canadians bought 4,000 examples in 2009.

The 2006 Infiniti M became the brand’s flagship sedan after the larger Q45 was dropped the following year. It could be argued that the smaller M was a better all-round car, offering a choice of V6 or V8 power to the Q’s V8-only powertrain. The engines were familiar: the M35 used the Nissan/Infiniti “corporate” 3.5-litre V6 (280 hp; 270 lb-ft) while the M45 was powered by the 4.5-litre V8 (335 hp; 340 lb-ft) that powered the Q45 and FX45 crossover.

The M was a rear-drive car in base form, but all-wheel drive was offered, initially with the smaller engine only; all-wheel drive models are distinguished by an ‘x’ appended to the model name (M35x, for example). The only transmission offered was a five-speed automatic.

2006 Infiniti M35x
2006 Infiniti M35x
2006 Infiniti M35x
2006 Infiniti M35x; photos by Greg Wilson. Click image to enlarge

2007 models got a mid-cycle refresh that included a new V8/all-wheel drive M45x model and revised styling; the engines’ power outputs were revised too, to 275 hp/268 lb-ft for the six-cylinder engine, 325 hp/336 lb-ft from the V8.

In 2009, six-cylinder cars became all-wheel drive-only (M35x), and that model also got a new 3.5-litre V6 making 303 hp/262 lb-ft. The M45 was notable for its use of Infiniti’s Rear Active Steer, which makes automatic adjustments to the rear suspension to improve both low-speed manoeuvrability and high-speed stability.

Fuel consumption in 2006 models was rated 13.2/8.6 L/100 km (city/highway) in RWD V6 models and 13.3/9.0 with all-wheel drive; and 13.5/9.4 in V8 form. Adding AWD to the V8 in 2008 models boosted consumption to 15.1/10.2 L/100 km, while the 2009’s new V6 was rated at 13.3/9.1.

Reliability-wise, Consumer Reports gives the M better than average used vehicle ratings for 2006 through 2008 (it doesn’t have data for 2009), and recommends it as a Good Bet.

Trouble spots, then, are few: brakes suffering from premature wear, squeaking and rotor (brake disc) warpage are common, especially in V8 models.

The M35x gets a below average rating in CR’s suspension category, which is probably related to the car’s susceptibility to “tramlining,” or the tendency to follow ruts in the road. CR only mentions it in relation to the one specific model, but discussions in Infiniti web forums suggests it’s a problem in all M models. The car’s stock Goodyear Eagle RS-A tires appear to be particularly bad for tramlining, and a few posters online said that switching tires did a lot to improve the car’s performance on rutted roads.

2006 Infiniti M45
2006 Infiniti M45
2006 Infiniti M45. Top photo courtesy Nissan/Infiniti; bottom photo by Laurance Yap. Click image to enlarge

A number of owners posting online complain of noisy suspensions that seem to be caused mostly by loose rear sway bars.

The M’s navigation system is a source of hassle; this thread at NicoClub.com provides a good overview of what specific problems owners have with their cars’ systems.

The M is also prone to a fuel gauge problem that affects a number of Infiniti models. The majority of posts in this thread are by owners of first-generation M owners, but it does affect second-gen cars, too.

From the Insurance Institute for Highway Safety (IIHS), the M earned “good” ratings in both frontal offset and side impact crash tests; the National Highway Traffic Safety Administration (NHTSA) didn’t test the M.

According to Canadian Black Book, used values range from $27,900 for a 2006 M35 to $55,275 for a 2009 M45x. In comparison, a BMW 5 Series is worth $29,225 for a 2006 530i, to $70,500 for a 2009, V8-powered 550i, while an Audi A6 will cost somewhere in the neighbourhood of $29,600 for a 2006 base sedan model, to $56,225 for a 2009 V8 model. There’s also the Mercedes-Benz E-Class, which rings in at $27,750 for a 2006 E350 and ranges up to $64,200 for a 2009 E550.

2006 Infiniti M45
2006 Infiniti M35x; photo by Paul Williams. Click image to enlarge

The value of the high-end BMW and Benz aside, the near-parity between the Infiniti’s values and those of the 5er and A6 is surprising; German cars usually hold their value far better than comparable Asian models. Other competitors include the Acura RL and Lexus GS, as well as the Cadillac CTS and Lincoln LS/MKS, with the domestics being the bargains of the bunch.

The M35/45 looks like one of the more predictably reliable cars in the class, even faring better than the Lexus GS in long-term reliability, according to Consumer Reports. That makes it a solid bet for shoppers looking for a big, powerful sedan; my only advice would be to avoid the trouble-prone navigation option. As always, look for a used model that comes with service records and that passes an inspection by a trusted mechanic.


Black Book Pricing (avg. retail) xxx:

Price today
Price new
M45 Sport
M45 Sport
M45 Sport
M45 Sport

Online resources
  • The M35/M45 forum at NicoClub.com is full of good information, though for research purposes, a single thread dedicated to reliability issues would be a big help. Same goes for the M section at InfinitiForum.net, which is also a quieter place than the same section at NicoClub.com.
  • Transport Canada Recall Number: 2009283; Units affected: 18,358 (affects other models)

    2008-2010: On certain vehicles, material in the nut used to secure the sensor-transmitter of the Tire Pressure Monitoring System (TPMS) may corrode and crack in areas with heavy concentrations of road salt. If this occurs, the nut may come out of the TPMS sensor-transmitter causing a rapid loss of tire air pressure. This could adversely affect vehicle control and cause a crash resulting in property damage, personal injury or death. Correction: Dealers will replace the TPMS nut with a revised version.

    Crash test results
  • National Highway Traffic Safety Administration (NHTSA)
  • Insurance Institute for Highway Safety (IIHS)

    Used vehicle prices vary depending on factors such as general condition, odometer reading, usage history and options fitted. Always have a used vehicle checked by an experienced auto technician before you buy.

    For information on recalls, see Transport Canada’s web-site, www.tc.gc.ca, or the U.S. National Highway Transportation Administration (NHTSA)web-site, www.nhtsa.dot.gov.

    For information on vehicle service bulletins issued by the manufacturer, visit www.nhtsa.dot.gov.

    For information on consumer complaints about specific models, see www.lemonaidcars.com.

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