 2005 Pontiac G6; photo by Grant Yoxon. Click image to enlarge |
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By Chris Chase
The Pontiac G6 was the 2005 replacement for the Grand Am, a name that had graced many different cars since 1973. At the outset, the G6 was a much better car than the last Grand Am: it looked and drove better, but the elimination of the well-known Grand Am name suggested that Pontiac wanted to start fresh in the mid-size segment and try to erase the Grand Am’s legacy of so-so quality and performance.
First-year G6s were all sedans, all powered by a 3.5-litre V6, whose 200 horsepower was a good starting point for a car in this class. The only transmission was a four-speed automatic.
In 2006, the G6 line was expanded to include a coupe and a folding-hardtop convertible. New powertrain choices were added, too: the sedan could be had with a 2.4-litre four-cylinder with 167 horsepower, while all three bodystyles could be had with either the 3.5-litre V6 or a 3.9-litre six-cylinder making 240 horsepower. Sedans and coupes with the larger V6 could be ordered with a six-speed manual, too, though the convertible was stuck with the automatic regardless of engine choice.
  2006 Pontiac G6 GTP coupe (top, by Laurance Yap); 2007 Pontiac G6 Convertible (bottom, by Chris Chase). Click image to enlarge |
Fuel consumption figures range from 10.0/6.4 L/100 km (city/highway) for the four-cylinder and 11.7/7.7 for the 3.5-litre. The 3.9-litre engine was rated at 13.1/8.6 with the automatic transmission, and 13.3/7.6 with the manual.
In 2007, a 252-horsepower, 3.6-litre V6 became standard in the top-trim GTP model, with the 3.9-litre being made an option in coupes and convertible models; the GTP convertible was dropped. The 3.6-litre was matched with a six-speed automatic transmission, and fuel consumption rated at 11.9/7.6 L/100 km (city/highway).
More changes came in 2008, with a new GXP trim designation replacing the GTP. This model still used the 3.6-litre engine with six-speed automatic transmission; the 3.9-litre engine was only available in the convertible, and the switch from it to the 3.6-litre engine meant the elimination of a manual transmission option. Fuel consumption for the four-cylinder improved notably, to 9.6/6.5 L/100 km (city/highway). You may also wish to note that the 3.9-litre was de-tuned in 2008 (probably in deference to the more modern 3.6-litre engine) to make 222 hp, down from its previous 240 horses.
In 2009, the six-speed automatic was made available with the four-cylinder engine, a move that further improved that motor’s performance at the pumps, to 9.4/5.9 L/100 km (city/highway).
 2005 Pontiac G6; by Grant Yoxon. Click image to enlarge |
When a car comes with a reputation as lackluster as the Grand Am’s was, the hope is that a completely new model like the G6 will bring with it better quality. In some ways, this did happen: the 3.5-litre V6 is said to have eliminated the gasket issues that plagued the previous 3.4-litre, and the four-cylinder was a brand new, and much more refined and efficient engine than the 2.2-litre that it replaced. But with the G6’s new design came some new problems.
The most serious issue that affects the G6 is that of steering that locks up unexpectedly while the car is being driven (does that ever not happen unexpectedly?). It was a big enough problem to prompt the folks who run the forums at G6OwnersClub.com to dedicate a discussion section entirely to the issue. This problem appears to affect 2005 model year cars; the exact cause appears to be a mystery, but the best guess I found is that the problem is linked to the electric power steering system used in some G6 models. See this thread at GMInsideNews.com for information on the topic.
 2006 Pontiac G6 GTP coupe; by Laurance Yap. Click image to enlarge |
All 2005 models (all of which were V6-powered) used electric power steering, but the incorporation of a more traditional hydraulic system in later models suggests that GM was aware of the problem with the electric setup: in 2006, all G6 sedans got the electric system, while the GTP coupe and all convertible models used a hydraulic system. By 2007, all six-cylinder G6s used the hydraulic setup, which four-cylinder models continued with the electric system, and this was also the case through 2008 and 2009.
A clunk in the steering caused by a bad intermediate shaft in the G6′s steering column is common, too; this also affects the mechanically-similar Malibu and Saturn Aura. For more information, click here, here and here.
In the Malibu, another pervasive problem is a slight vibration at speeds between 60 and 100 km/h. As far as I can tell, the cause has never been determined, but guesses made by Malibu owners and the mechanics who’ve tried fixing their cars include out-of-round tires and erratic six-speed transmission performance. Given the G6’s mechanical similarities, this could be something to watch out for. Click here and here.
