2008 Pontiac G8 Long Term Road Test - Maintenance

2008 Pontiac G8 Long Term Road Test

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2008 Pontiac G8 GT: Lab Results on 13,000-Mile Oil

January 07, 2010


Just before we sold our 2008 Pontiac G8 GT the oil change indicator came on. We had driven an amazing 13,000 miles without changing the oil. We were curious to know whether this was too long between changes or whether we could have kept rolling. We sent a sample of the oil off to Blackstone Laboratories to have them check the quality.

Here's what the lab had to say. And we also have some thoughts from our Edmunds engineering editor.

First, the report from Blackstone, which was emailed to us as a pdf. It lists all the trace metal levels and other technical data. But it also summarizes the report:

"13,000 miles on the oil seems to have worked pretty well for you. Copper, from brass/bronze
parts, was a bit high but with everything else looking good we just can't bring ourselves to get too upset about it. The average oil run for the GM 6.0L is just ~4,500 miles so your engine wears far better than most. You could try going a little longer but the excess wear metals make the oil abrasive and may limit how long you can go. Try 14,000 miles next time. The TBN read 1.5 so you still had some active additive left, though not much. 1.0 is too low."

We forwarded the report to Jason Kavanagh, Edmunds Engineering Editor and he had a few comments and explanations.

"TBN is Total Base Number, AKA detergency," Kavanagh reported. "Basically, new oil is inherently 'basic' in order to neutralize the acidity that is produced in an engine over time (that would be represented by TAN, or Total Acid Number).

"New oil has high TBN. Once an oil's TBN gets low, even if all else in the analysis is 'good,' the oil is essentially used up. It can no longer neutralize the acidity which, left unchecked, will damage internal engine components.

"It looks like 13k miles was fine for the G8," Kavanagh said. He went on to explain, "The copper and other wear metals are basically tiny bits of the engine suspended in the oil. Copper is from the bearings. Aluminum is the block/heads. And so on. Things like phosporus and manganese are part of the oil's additive pack. Basically, in UOA, you want these to be high, and the wear metals low."

So the verdict seems to be that the GM sensor accurately measured the effectiveness of the engine oil. Most of the oil was used up but not all of it. If we still owned the car, I don't think we would push the interval any higher. Going this long seemed almost like driving on borrowed time. Especially since many of our other vehicles seem to need new oil after only 7,500 miles.

I'm surprised that GM dealers aren't up in arms about this cutting into their revenue stream. A steady parade of driver's asking for oil changes is a nice chance to upsell them other services and boost dealership profits.

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2008 Pontiac G8 GT: 13,000 Mile Oil Change Interval

December 26, 2009


The oil sensor in our 2008 Pontiac G8 GT finally told us it was time for an oil change. We checked records and the last time we got new oil was 13,000 miles ago! We wanted to send an oil sample off to Blackstone Laboratories to see what they could tell us about the condition of the oil. We wanted to know if the oil was truly done, as the sensor indicated, or whether there was any life left in the slippery stuff.

Our first stop was to look in the owner's manual to see what Pontiac had to say about oil changes.

"When the system has calculated that oil life has been diminished, it will indicate that an oil change is necessary. ... It is possible that, if you are driving under the best conditions, the oil life system might not indicate that an oil change is necessary for over a year. However, the engine oil and filter must be changed at least once a year."

Still, we were curious about the condition of the oil and why the sensor finally went off. We tried to use the "vampire gun" that Blackstone gave us to suck out a sample by inserting a long tube down the dipstick opening into the oil pan. However, we came up dry. We took the G8 to Boulevard Buick Pontaic GMC, in Signal Hill, CA, where the service advisor said the baffle over the oil pan prevented anything but the dipstick from being inserted. We asked him to keep a sample for us while doing the oil change.

By the way, the oil change, inspections and tire rotation was only $39.95. It took them two hours to do the service and clear two recalls. We'll report back on the condition of the oil after we hear from Blackstone labs.

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2008 G8 GT: Little Things Make a Big Difference

December 18, 2009


How can we even dream about selling our 2008 Pontiac G8 GT when there is a huge scratch under the driver's door handle? It's the first thing a buyer would see on a test drive.

Some folks from Turtle Wax came by and showed me this product so I thought I'd give it a try. Michael Deddo, Turtle's senior research chemist, said the scratch was probably just in the clear coat. He was right as you will see in the before and after pictures on the next page.

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2008 Pontiac G8 GT: Brakelight Fix-it Ticket

September 18, 2009


"There is an auto parts store in town. Should be easy to just stop in there and get a new bulb." That was the advice given to us by the CHP officer writing a citation for the burnt out driver-side brakelight on our 2008 Pontiac G8.

We couldn't remember the last time we were issued a fix-it ticket. But the voice in our head was reassuring, "Spend a couple of bucks on a new bulb, replace it and have the next cop we see sign it off. Then mail it in. Done." Well, it wasn't quite as simple as our internal advisor remembered.

A new bulb set us back $5 and we replaced it in 10 minutes. Easy. We searched out our nearest certification station to approve the work, and found it closed. With some effort we found the next closest station. We pulled up and the inspector said, "Yep, it works. That will be $40. There is a correction fee of $25 and inspection fee of $15."

Disgusted, we handed over our debit card to pay the charges and were greeted with, "Cash only, sir." In our pocket sat exactly $27.26 worth of not enough. We left to find an ATM, withdrew the cash and returned to pay the fees. This wasn't what we expected.

We'll have to remind our inner voice that these fix-it tickets aren't so easy after all.

Mike Schmidt, Vehicle Testing Manager @ 30,833 miles

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2008 Pontiac G8 GT: Fresh Meats

July 20, 2009

G8 Stokes.jpg

As Dan Edmunds said back when the 2008 Pontiac G8 was our Car of the Week, the rear tires were dead and gone and needed immediate replacement. And by immediate, we meant right after we had some more fun with worthless rubber.

Anyway, a new set 245/40R19 Bridgestone Potenza REO50As ran us, including installation and tax, $684.67 and took just about an hour from the time we called until we drove off with new shoes.

I can't figure out why the fronts were fine and the rears were so worn down.

Mike Magrath, Vehicle Testing Assistant @ 25,112 miles

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2008 Pontiac G8 GT and 2008 Cadillac CTS V6: Dealer Differences

July 03, 2009

G8 Service reciept.jpg

So I get asked all the time, "Hey, what's the difference between dealerships?" "What happens when a dealership has both premium and non-premium brands under the same service roof?" Well, here's a good visual representation for the only difference in service when you bring a premium (Cadillac CTS-- Top) and a non-premium (Pontiac G8 GT -- Bottom) to the same dealer (Martin Cadillac in LA). Notice the difference? That's the only one.

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2008 Pontiac G8: Oil Change and Brake Check

July 03, 2009

G8 Service Blog.jpg

Just about a week-or-so ago, we brought our 2008 Pontiac G8 over to The Martin Automotive Group in LA for its second called-for oil change. While we were there, we wanted them to check out a vibration we were getting through the brake pedal, and to replace the flip-style key that had long ago stopped flipping.

When we arrived we waited a solid 15 minutes before someone spoke to us, and even then it was only the lot attendant asking us to back up so they could get that limo around. Another 10 minutes passed and a service advisor beckoned. They said, contrary to what they'd said earlier that morning, that they were quite busy ( good for them I suppose) and if we wanted the brakes inspected we'd have to leave the car with them overnight.

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2008 Pontiac G8 GT: Dipstick? What Dipstick?

June 26, 2009

555 castrol-use-your-dipstick.jpg

Our excitable Scottish tie-wearing mechanic friend implores folks to "Think with your dipstick!" He's so fanatically passionate about the benefits of regular lubracatory monitoring practices that he'll even resort to physical violence to force people to submit to his agenda.

None of us around here wants that, least of all me.

And while our favorite demented Scot is primarily focused on engine oil, it pays to keep tabs on your transmission fluid level, too.

I thought of this while driving the Pontiac G8 GT the other day, as the shifting action didn't seem to be as crisp or regular is it did when it was new, especially in the "normal" shift mode. (Sport mode seems fine.) And I'm not the only one who has experienced this.

The slight shifting delay I noticed once or twice while starting from rest reminded me of what low automatic transmission fluid feels like, so I popped the hood for a quick check.

Imagine my surprise when I discovered that I couldn't. Why? No dipstick.

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2008 Pontiac G8 GT: It's Finally Time for the Second Oil Change

June 05, 2009


Last night, I started our long-term 2008 Pontiac G8 GT, and the car flashed the above message (at 22,788 miles). Finally. It has been 11,540 miles since our first oil change seven months ago.

I like the warning system in this car. In addition to the 30-second flashing warning at startup, there's another reminder right after you shut the engine off. So even if you've managed to forget your car needs an oil change in the course of a commute, you get that extra nudge to call up the dealer as soon as you stop.

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2008 Pontiac G8 GT: 20k Mile Tire Wear Update

May 05, 2009

car-of-the-week-banner.jpg 555 tire update oa size.jpg

Recently we talked about the sticky 18" tires on our new 2009 BMW M3. Well, our 2008 Pontiac G8 GT has sticky shoes, too, and they're fast-approaching the 21,000 mile mark.

And these Bridgestone Potenza RE 050A tires are Z-rated, as well -- sort of. That's because the ill-defined Z rating ( >149mph) was split into two clearly-defined "W" and "Y" ratings a few years back. The G8's skins are of the W-rated sub-category, and that makes them good up to 168 mph (270 kph).

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2008 Pontiac G8 GT: Needs Another Quart

April 28, 2009

addoiltog8.jpg I checked the oil in our long-term 2008 Pontiac G8 GT today, and it registered below the low mark. I've come to know that this means the car is down a quart . So I gave it a bottle of 5W30.

Believe it or not, we haven't been neglecting the car. Oil service intervals are computer-indicated on the G8; there's a shot of the owner's manual in the thumbs below. And since its last service at 11,800 miles, the maintenance light has yet to illuminate again.

A check of the Edmunds Maintenance Calculator suggests that 12,000 miles is the absolute longest you could expect to go between changes and the owner's manual notes that you shouldn't go longer than 10 months -- we've reached neither threshold.

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2008 Pontiac G8 GT: Feels Best at 92 MPH

December 04, 2008


I drove our long-term Pontiac G8 GT 420 miles to the Napa Valley yesterday -- St. Helena to be exact -- and I am quite happy with my choice. The G8 is an excellent high-speed cruiser. The cabin is quiet and the seats are wide and roomy, yet supportive enough for a half-day behind the wheel.

Though I know the suspension was softened somewhat from the Holden version, there's still an edge to it that I didn't quite expect from such a big car. Whenever I hit a rut or joint, I felt the exact shape, size and severity of the impact through the driver seat. It's fine, though. And far better than an isolating ride.

Every time my thoughts drifted slightly from the task at hand, I'd look down to see I was traveling at 92 mph. So I think this is the car's happy zone. Of course, I often added to this during passing maneuvers, and the 6.0-liter V8 showed few signs of strain. It reminded me of my inaugural road trip in the GT-R. I grew to like the small-block V8's low roar, too.

I'd neglected to check the oil before leaving, so I tended to this after fueling up in St. Helena. It was indeed low -- oil registered on the dipstick but below the "low" mark. I bought a quart of 5W30 and added half of it. I drove a couple miles more to my hotel and checked it again. Still low. So I added the rest and will recheck before leaving town.

The car's fuel log indicates that Brian Moody also added a quart at 10,693 miles, so apparently, the G8 does like some oil between changes. (It was last serviced at 11,247 miles.) At least, it's the regular old stuff that you can buy at any gas station.

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2008 Pontiac G8 GT: Cheaper than the Smart...

November 06, 2008


...well, at least as far as a routine oil-change-and-glance-at-the-fluid-reservoirs service goes.

We had the G8 GT in for said service recently and the tab came to just $32.48. Keep in mind that's for a big V8. The smart just had a similar service as I'm sure you all saw, and it cost $211. So it cost over six times that for the smart which has an engine one-sixth the size.

So there's another advantage (other than not giving you whiplash upon gearchanges) that our G8 has over the fortwo. Yes, I know the G8 is really an Australian GM product, but it's sold and serviced as a Pontiac. These days, our country could use a little pride -- USA! USA! USA!

John DiPietro, Automotive Editor @ ~ 11,800 miles.

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2008 Pontiac G8 GT: FIXED!

July 25, 2008


Fourteen (14) days ago I dropped our 2008 Pontiac G8 GT at Martin Cadillac in Los Angeles to fix a malfunctioning traction control with the promise of a quick, easy fix and same day return. Wednesday night we picked up our Pontiac, fixed, from Hooman Pontiac in Culver City.

What follows is a tale of deceit, frustration, anger, a damn-fine commitment to service from Pontiac and international espionage, though that last bit can't be discussed... >

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2008 Pontiac G8 GT: Six days waiting

July 16, 2008


Remember my blog last Friday? The one where I took our 2008 Pontiac G8 GT to Martin Pontiac in Los Angeles for a malfunctioning traction control light and the service advisor said it was an easy fix, and that it would be done by the end of the day? Ringing any bells?

Well, it's been six days now and the G8 is still in the dealer's possession. I had to call them on Tuesday to find out what was going on. They don't seem too keen on informing their customers. Or being nice to them. The service advisor we have doesn't understand the service, or advisor, aspects of his job.

After a few calls I got to the bottom of it: It was not, as they suspected, the wheel speed sensor. The cause of our traction woes was a brake sensor. A brake sensor that GM's parts dept. can't get because they don't have a part number for it.

So, it's been six days and there's no light visible at the end of the tunnel. We'll keep you posted.

Mike Magrath, Vehicle Testing Assistant @ 6,626 miles

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2008 Pontiac G8 GT: Traction (control) Trouble

July 11, 2008


Who doesn't love a good powerslide? I mean good, smoky, high-speed hooliganism. The type of slide where slip angle matches velocity and the road is coming at the driver through one of the side windows.

Problem is, they're not the most low-key form of driving excitement. The neighbors, and the local constabulary, may take notice if someone were to enter their neighborhood in this fashion.

Our long-term Pontiac G8 cares not for neighbors or the police. We have, apparently, been too kind to our V8. On the way home the other night with Executive Editor Michael Jordan, the G8 decided to live on the wild side and turn the traction control off. By itself. On the highway. It wants us to be bad. It's daring us.

If it starts calling us Dave, though, I'm driving it into the ocean.

While some of our staffers thought this would be great fun, other more rational heads prevailed and I took it to the Martin Automotive Group in Los Angeles.

"Does it have aftermarket wheels?" our service advisor asked. Nope. "Is it lowered?" Nope. "Hmm, this is the first time I've seen this issue on a car without rims or a lowering kit. It's a common issue on the CTS and this car with big wheels or when lowered."

By 'this issue' he means a failed wheel-speed sensor. The issue he's talking about is a malfunctioning wheel-speed sensor that talks to the stability control system. He said that it was an easy fix and we'd have it back later this afternoon.

Mike Magrath, Vehicle Testing Assistant @ 6,626 miles

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