2010 GMC Terrain Long-Term Road Test - Maintenance

2010 GMC Terrain Long-Term Road Test

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2010 GMC Terrain: Saga Of The Dead Signal Lamp

January 06, 2011

Noticed last night on my way home that the Terrain's right turn signal was out. When activated it exhibited the classic "fast blink" symptom I remember from my bulb-slaying high school ride. The video tells the story and reveals the culprit. Left turn signal shown first as standard.

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2010 GMC Terrain: "Top Kill" DIY Oil Change Video

October 08, 2010


In our last episode, Blackstone Laboratories suggested we change the oil now rather than wait until the oil life monitor told us to. Why? Our 2010 GMC Terrain is still new-ish, and Blackstone saw a few more residual break-in metals than they'd like to see in a sample of our current oil.

That gave me an excuse to try something I'd had in mind for a while: a stand-up or, as I like to call it, a "Top Kill" oil change. Instead of diving deep under the sea car, I'm going to do the whole job topside, from right under the hood.

This works because the GMC Terrain's 2.4-liter Ecotec engine has a cartridge-style oil filter. On top of that, Edmunds co-conspirator Phil Reed lent me his vacuum oil extractor.

Follow the jump to see a video of the process.

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2010 GMC Terrain: Oil Sample Analysis Results

September 30, 2010


Just over a week ago, I took an oil sample from our 2010 GMC Terrain and sent it to Blackstone Labs in Fort Wayne, Indiana, for analysis. Our GMC's built-in oil life monitor was telling us that the oil could last something like 10,000 or 11,000 miles, so I pulled 3 ounces from the crankcase when the oil had 5,731 miles under its belt (and the engine had 15,000-odd miles) to see what the oil had to say for itself.

In short, Blackstone told us we should change the oil sooner rather than later -- within the next thousand miles. Not every time, mind you, but this time, at least.

I talked to Ryan Stark of Blackstone Labs to understand why they're telling us this. Those are my scribbled notes, not his.

First, a recap of the basics:

The last change was done by a dealer at 9,615 miles, 5,731 miles ago. This was also the first oil change, as we had followed the owners manual's advice and keyed off the Terrain's on-board oil life monitor for the interval.

We have no way of knowing exactly what sort of oil the dealer put in, but the oil filler cap says that 5w30 is the right stuff. They did affix a tag to the windshield reminding us to come in 3 months or 3,000 miles. This little upselling gem set me off and got me digging into the subject.

Here are the highlights of Blackstone's results:

The average oil change interval for this engine family is 5,195 miles. But that's not the suggested oil change interval, by Blackstone or by GMC. This is nothing more than the average oil mileage at which all other Ecotech 2.4 samples were sent in to Blackstone for analysis. It's a measure of owner behavior. We can breeze right past this and look at the results themselves.

Our Terrain's oil viscosity measures 5w20. It's impossible to tell if the dealer installed 5w20 or 5w30 initially, because Ryan said "it could have sheared down". He went on to say this doesn't matter too much, because the ideal viscosity range has more to do with the local outdoor start-up temperature. They don't see a strong correlation between engine wear rates and oil viscosity in their historical database.

Certain wear metals (they measure 20 different ones) were detected at higher levels than would be expected for the typical "broken-in" engine. Iron is as 47 ppm instead of 12; Molybdenum is at 178 ppm instead of 64; Silicon is at 18 ppm instead of 11; Copper is at 7 ppm instead of 3 ppm. Most of the others are close to the norm. But Ryan says this does not mean the engine is still breaking in -- he says that wear-in is over and done with in the first 100 to 1,000 miles of operation.

What Blackstone is instead saying is these break-in "residuals" float around in there and hide in nooks and crannies within the block and head, something the oil life monitor may not account for in all cases. Oil and filter changes are the best way to get the stuff out, and you want it out because it's potentially abrasive stuff. While every engine design behaves differently with regard to this tendency, Blackstone thinks it would have been better in this case if we had gone with 4,000 to 5,000-mile intervals for the first three oil changes before we started to follow the oil life monitor's recommendation.

TBN is the Total Base Number of the oil. Jim, Ryan's dad, reminded me you can't run a pH test on a non-aqueous solution such as hydrocarbons, so the TBN test is run instead to measure how "basic" the oil is. The Total Base Number is a rough measure of the active level of detergent dispersants in the oil, additives that are there to keep dirt and solids in suspension so they can be captured by the oil filter.

Our oil's TBN is 1.8, and the recommended minimum is 1.0. But Ryan wasn't too concerned about this because he likes to focus on the number right below it on the report, the Insolubles Percentage. Our IP is still quite good at 0.2 compared to a target of 0.6 or less. He says that this tells him the detergent and filter are still doing a good job, whatever the TBN happens to be. From an insolubles and filtration standpoint, 10,000 miles still isn't out of the question.

He says the TBN test is more applicable to diesels, and it's more of a legacy test that some customers want to see. Oil (and detergent) sales and marketing efforts of the past used to tout their product's TBN as a measure of superiority versus the competition. (Remember Grandma's "Basic H" all-purpose cleaner? - I didn't until just now). They still run the TBN test for those that request it, but it's not part of the standard Blackstone test protocol. The Insolubles Percentage test, however, is standard.

The bottom line:

Ryan says the level of wear-in residuals is not alarming for an Ecotec engine of this relatively young age, but they are higher than he'd like to see. Blackstone suggests that we change the oil to get the levels down sooner rather than later. That said, the oil life monitor has not led us down the garden path into serious trouble. Oil life monitors are fine, he says, but the break-in residual issue leads him to recommend a more traditional timetable of 4,000 to 5,000 miles for the first two or three oil changes.

It's likely that Blackstone's conservative position on this comes from their typical customer -- fleet managers and trucking companies. These folks don't just want 100,000 miles of engine life, they want 300,000 miles and up, if they can get it. But they also don't want to spend any more money on maintenance and downtime then they need to. Strategic maintenance with an eye toward ultra-long engine life is their goal.

What's GM's take on these results? We'll see what we can find out and let you know.

In the meantime, can you guess what comes next? That's right, a GMC Terrain DIY oil-change post. But this one is going to be a bit different from the others I've done in the long-term fleet. That's as much of a hint as you're going to get.

Dan Edmunds, Director of Vehicle Testing

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2010 GMC Terrain: Collecting an Oil Sample for Analysis

September 19, 2010


The last time a dealer laid hands on our 2010 GMC Terrain, they put a sticker on the windshield reminding us to come in for our next change at 3,000 miles or 3 months. Wrong!

Modern cars and the modern oils they run don't need such frequent changes. And this very GMC Terrain has a built-in oil life monitor that tells the driver exactly when the next change is due, right on the dash. And the calculation it makes is based on driving style and conditions, not straight time or mileage. Our dealer's scare tactics are nothing more than attempt to get into our wallet.

At the same moment our Terrain's oil was 4,000 miles old -- 1,000 miles past the dealer's "recommendation" -- the Terrain's own on-board oil life monitor was telling us the oil still had 60% of its life left. In other words, a 10,000 mile oil-change interval was going to be cool.

Since then, the Terrain has been on some easygoing road trips. With 5,731 miles on the oil, the oil life monitor now says the oil has 48% of its life left. The projected oil life is up over 11,000 miles because of our recent light-duty use.

But does the oil life monitor really have things all figured out? Will this oil still have what it takes 5,000 miles from now?

I decided to pull a sample and send it to a laboratory for analysis. Blackstone Labs in Fort Wayne, Indiana will do it for between $25 and $35.

The standard $25 test tells you how your engine is doing, based on an analysis of the metal and "insolubles" in the sample. A worthwhile option is the $10 TBN or Total Base Number test. This is the test that measures properties related to oil life.

It's clear that we have time on our side. Before we change our Terrain's oil, we're going to send a sample in for a TBN test. Here's how we pulled the sample you see above.

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2010 GMC Terrain: Can You Trust Mr. Goodwrench?

September 03, 2010


This GM Goodwrench maintenance reminder sticker appears on the windshield of our 2010 GMC Terrain. As you can see, it's telling us that the next service is due at 12,615 miles or Sep. 30th, (whichever comes first, presumably), at which time we'll need to change-out the 5W30 motor oil.

I asked Mike to check our records, "When was the last oil change?"

"June 30th at 9,615 miles," said Mike.

You don't need a calculator to figure out that works out to EXACTLY 3 months or 3,000 miles.

I glanced at the odometer. It read 13,636 miles, just about 1,000 miles over. We've got just over 4,000 miles on this oil. Mr. Goodwrench will not be pleased.

2010 GMC Terrain: Wash Day

August 30, 2010


We wash our long-term fleet cars every Monday, weather permitting. The GMC Terrain wasn't terribly dirty. I don't have kids so the interior wasn't covered in animal crackers or anything like that but the outside was a little grimy.

If it were my car, I would have let it go longer. But it's not, so I followed our rules.

How often do you wash your car?

Donna DeRosa, Managing Editor @13,333 miles

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2010 GMC Terrain: Time for an Oil Change?

July 01, 2010

2010 GMC Terrain Oil Change.jpg

Sharp marbles that we are, we picked up on the subtle hints our 2010 GMC Terrain was throwing our way in the instrument cluster about an impending oil change (though we've added some, oil life was still impressive at 9,615 miles). For the vital fluid swap, we headed down to our nearest dealer, Martin GMC, following the cops into the service bay.

With no appointment we were greeted promptly and spoke with service advisor Marlene Bobrowsky. Beyond the regular oil service Marlene recommended a tire rotation and balance, but because The Mikes hadn't signed off on that we just went with the lube job. We waited for the truck, and downtime including a scrubbin' in the carwash was about 90 minutes. Total charge: $40.67. Invoice after the jump so you can howl about us spending too much.

Paul Seredynski, Executive Editor @ 9,615 miles

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2010 GMC Terrain: Actuator Strut Replacement

May 20, 2010

GMC terrain actuator.jpg

Well, after a few mis-steps, Martin Cadillac finally got the correct part in to fix out 2010 GMC Terrain's leaky liftgate actuator strut. We dropped the car off this morning and they called around 1 saying it was ready to be picked up at any time.

Days out of service: 0

Total Cost: 0

Mike Magrath, Vehicle Testing Assistant @ 7,823

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2010 GMC Terrain: Added Some Oil

May 10, 2010


On Saturday morning I decided to check the oil level in the engine of our long-term 2010 GMC Terrain. It was low. Real low. Like it was hardly registering on the dipstick.

It took more than a quart before it was full.

Scott Oldham, Editor in Chief @ 7,422 miles

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