Oil change in a 2006 GMC Envoy with 138,000km

[squatchy]

Hello,

I recently purchased my 2006 GMC Envoy 4.2L I-6 about a year ago (used obviously). At that time, it had ~129,000km on it and I had an oil change done at the GM dealer. I want to start doing my own work on the car, and I've been getting some really conflicting advice about oil changes: specifically, what OCI and which oil I should be using.

I called up my dealer and one person started telling me that I need Dexos 1 oil and I was like [censored] is that I don't think I've heard of it before... Long story short, I found that it's not even required for vehicles older than 2011. My service rep told me that you should just go by the GM Oil Life Monitor (when it gets to 10%) or every year if you don't get to 10% in a year - that seemed reasonable.

Moving on to oil - the owner's manual says 5W-30 and my the car has been serviced at the dealer from when it was new until now (so conventional oil is my guess). Right now, I'm seeing Castrol GTX 5W-30 at CAD $54.99 / 12L (CAD $4.58 / L or USD $3.33 / qt) at Costco but I dropped by Canadian Tire to pick up a filter and noticed that Penzoil Platinum was on sale for CAD $31 / 5L (CAD $6.2 / L or USD $4.5 / qt). The dealer people were adamant that I should never switch from conventional to synthetic with my mileage... so I held off on making a decision. Is that something I need to be worried about?

Should I consider moving to synthetic if the price is comparable? Sometimes, clearance synthetics are within $1-2 / L of conventional so that seems pretty good. If I do make the move, and given my mileage, do I need to stick with synthetic from then on (or is that a myth)? From what I can tell, the car has been maintained very well (it was a company car, so it was driven a lot - but maintenance was always done regularly and at the dealer). I checked the oil about a month ago and it was sitting happy in between the markings on the dipstick. Looked pretty black however...

Any advice? I'm new to car ownership, but I'm pretty handy and want to learn how to do these things on my own. Figured I'd make a post on here and have some informed people try to educate me!

Thanks!

 

[czbrian]

It was probably getting a synthetic blend since it was changed at the dealer which likely stocks and uses a Dexos certified oil. You can go to a synthetic or conventional depending on how much you want to spend or how long you want your OCI to be. I would just use another synthetic blend like Pennzoil Gold, Castrol Magnatec, Valvoline Maxlife, etc... and change when the monitor is around 10%.

 

[czbrian]

Originally Posted By: squatchy
Should I consider moving to synthetic if the price is comparable? Sometimes, clearance synthetics are within $1-2 / L of conventional so that seems pretty good. If I do make the move, and given my mileage, do I need to stick with synthetic from then on (or is that a myth)?


If you can get a good deal on the synthetic, go for it. You can change back to conventional or a blend later. Or if you find a really good deal, just buy a few years worth like others on this site.

 

[FCD]

Consider a High mileage full synthetic oil

 

[beanoil]

There is nothing special about that engine that requires anything beyond a conventional oil every 5-6k. Your filter will not have an anti-drain back valve, it's upside down and vertical. The oil pressure sensor is a known failure item, indicating no pressure at idle when there is. Don't put much faith in the oil pressure gauge, it is at the end of a line of conversions from the ECM, and is not accurate.

 

[JC1]

Where are you located in Canada? Synthetic is always good up here. I'm using Pennzoil Platinum myself and it's a very good oil (Esp when it's on sale). 5w-30 would probably be the best for your truck. Does the truck burn any oil?

How many kms do you drive in a year? What has been your avg OCI?

Canadian Tire and Walmart usually have good sales (check the flyers).

 

[squatchy]

Originally Posted By: JC1
Where are you located in Canada? Synthetic is always good up here. I'm using Pennzoil Platinum myself and it's a very good oil (Esp when it's on sale). 5w-30 would probably be the best for your truck. Does the truck burn any oil?

How many kms do you drive in a year? What has been your avg OCI?

Canadian Tire and Walmart usually have good sales (check the flyers).


I'm in Toronto - so definitely sticking with 5w-30 for the winter starts. Yeah, I'm tempted to get PP because it's on sale - but I was worried about the switch to synthetic from conventional. Again, the dealers were really adamant about not doing this - is it just fear mongering? What price do you usually see PP on sale for?

Truck isn't burning any oil to my knowledge, but then I have not been especially religious checking the oil - something I plan to do now that I'm taking care of it on my own. I don't drive too much - roughly 6,000-8,000km a year. Last oil change was a little over a year ago, when I bought the car. Before then, it was always done according to the OLM (since it was driven a lot, probably 1-2 times a year at the dealer).

 

[squatchy]

Originally Posted By: beanoil
The oil pressure sensor is a known failure item, indicating no pressure at idle when there is. Don't put much faith in the oil pressure gauge, it is at the end of a line of conversions from the ECM, and is not accurate.


I was just reading about this on some other forums... That's a little stupid - how are you supposed to tell if your oil pressure is okay? Is it just a switch that turns on at a set oil pressure? What about oil pressure being too high?

 

[Garak]

They call for dexos1, simply because GM consolidated their specifications. Any ordinary 5w-30 will do fine with the factory recommended oil change intervals. You certainly are free, however, to buy something more expensive.

 

[BrianF]

I have run synthetic since I bought my 06 TB with 25,000km on the clock. I was doing 10,000km oil changes until I started on this site. My oil life monitor gongs me at 16,000km intervals. I surmised that if the OLM is set up for conventional oil, running synthetic with a good filter should get me to the 20,000km mark with ease. Currently I run PPPP 5w30 and it runs great all year long. I think the girl is starting to use a touch of oil, maybe 1/2 a liter in that 20k span. It now has just shy of 200k on it.

I cleaned the camshaft actuator solenoid several months ago tracing down a rough idle. The thing came out [censored] near as clean as it was put in at the factory. Gave me an idea of how clean the inside of the engine is.

These things are not hard on oil. Use a decent brand and good filter to ensure she runs like a top. This thing runs 6.6 liters of oil for 4.2 liters of displacement.

I run synthetic because I run one type of oil all year and prefer one that flows well in the cold. Sometimes I forget to plug in during the winter time.

I usually get PPPP for 31 bucks before tax.

 

[IllinoisSparky]

Originally Posted By: squatchy
Hello,

I recently purchased my 2006 GMC Envoy 4.2L I-6 about a year ago (used obviously). At that time, it had ~129,000km on it and I had an oil change done at the GM dealer.

The dealer people were adamant that I should never switch from conventional to synthetic with my mileage... so I held off on making a decision. Is that something I need to be worried about?

Thanks!


I got the same line from the MB dealer after resurrecting a 1992 MB 190E - That they would not put synthetic oil in a car that old. 120k miles.
So, I did it myself for the last 3 years, and never had to add oil between oil changes.
They don't want to have people coming back whining about leaks or consumption.

If yours is not leaking or consuming oil, then don't worry about the switch.
And you can also switch back to dino after synthetic.
My 2004 Ford has been switched back and forth several times, and also never uses oil.

In northern climates, synthetic is your friend for cold starts!

 

[Falcon_LS]

Forget about set drain intervals, just follow the OLM. Forget the high mileage business, a decent synthetic blend or full synthetic would be the way to go IMHO.

Mine is an export model, calling for ACEA A3 oil in the manual. My assumption is the PCM programming may be slightly different. That said, I personally run full synthetic in mine and do a simple drain and refill at the 50% mark and change out the filter when I change the oil at 1% or so. It's anywhere between 16,000 - ~18,700 km for the OLM to hit 1%.

 

[squatchy]

Originally Posted By: BrianF
I have run synthetic since I bought my 06 TB with 25,000km on the clock. I was doing 10,000km oil changes until I started on this site. My oil life monitor gongs me at 16,000km intervals. I surmised that if the OLM is set up for conventional oil, running synthetic with a good filter should get me to the 20,000km mark with ease. Currently I run PPPP 5w30 and it runs great all year long. I think the girl is starting to use a touch of oil, maybe 1/2 a liter in that 20k span. It now has just shy of 200k on it.

I cleaned the camshaft actuator solenoid several months ago tracing down a rough idle. The thing came out [censored] near as clean as it was put in at the factory. Gave me an idea of how clean the inside of the engine is.

These things are not hard on oil. Use a decent brand and good filter to ensure she runs like a top. This thing runs 6.6 liters of oil for 4.2 liters of displacement.

I run synthetic because I run one type of oil all year and prefer one that flows well in the cold. Sometimes I forget to plug in during the winter time.

I usually get PPPP for 31 bucks before tax.


Nice - that's good to hear from a fellow Trailvoy owner

Yeah, I just noticed that Canadian Tire had a sale on PP for $31 and apparently Pennzoil has a mail-in-rebate going until the end of the year ($2 off per litre up to $48 per household)!

Out of curiosity (and quite unrelated), how did you get the knowledge to clean out the camshaft actuator solenoid? I feel like all the repairs I do is just off some Youtube videos and some forum posts. I want to learn how to do it properly, but don't really have the time to take a full course at a college. Any shops teach drop-in classes or something on weekends?

 

[squatchy]

Originally Posted By: Falcon_LS
That said, I personally run full synthetic in mine and do a simple drain and refill at the 50% mark and change out the filter when I change the oil at 1% or so. It's anywhere between 16,000 - ~18,700 km for the OLM to hit 1%.


Wow - I haven't heard of that before. So you drain out the old oil at 50% OLM and then put the same oil back in? What is the purpose of that? I've read that the OLM was designed for use with conventional oil, so I suppose it's fair to extend it for synthetic. I guess the only sure way to tell would be to do a used-oil analysis but I don't really know the process for that or if its worth it given the mileage on my car.

 

[FastLane]

Mobil 1 comes on sale all the time in Canada. Put 5W30 in it with a quality filter. Change it as you see fit. I still change it at 5000 kms. I would change your oil once a year.

 

[BrianF]

PPPP seems highly revered on this site and I find it cheaper than M1. Cambodian tire sells 4.4 liters of M1 for 35 or so bucks a liter and the PPPP is 31 or so for 5 liters.

I learned quite a lot on the maintenance side from trailvoy .com back in the day and now on gmtnation .com. Good formum for this platform.

 

[Falcon_LS]

Originally Posted By: squatchy
Originally Posted By: Falcon_LS
That said, I personally run full synthetic in mine and do a simple drain and refill at the 50% mark and change out the filter when I change the oil at 1% or so. It's anywhere between 16,000 - ~18,700 km for the OLM to hit 1%.


Wow - I haven't heard of that before. So you drain out the old oil at 50% OLM and then put the same oil back in? What is the purpose of that? I've read that the OLM was designed for use with conventional oil, so I suppose it's fair to extend it for synthetic. I guess the only sure way to tell would be to do a used-oil analysis but I don't really know the process for that or if its worth it given the mileage on my car.


I drain the sump at 50% and refill with 6 quarts of fresh oil, why would I waste my time draining and putting the same oil back in?

 

[artificialist]

Originally Posted By: squatchy
Originally Posted By: beanoil
The oil pressure sensor is a known failure item, indicating no pressure at idle when there is. Don't put much faith in the oil pressure gauge, it is at the end of a line of conversions from the ECM, and is not accurate.


I was just reading about this on some other forums... That's a little stupid - how are you supposed to tell if your oil pressure is okay? Is it just a switch that turns on at a set oil pressure? What about oil pressure being too high?

Some oil pressure switches also detect if the oil pressure is too high. That in mind, I have never seen a warning light for oil pressure being much higher than normal. It might set an error code, and depending on the situation that may illuminate the check engine light.

As for being able to know your exact oil pressure, there is a specialty tool for that. On one end is a hose fitting that threads into the oil pressure sender/switch hole, and on the other end is a mechanical oil pressure gauge. This means it can diagnose if the car has abnormal oil pressure, if the oil pressure switch doesn't function, or indicate that an electrical problem causes the analog oil pressure gauge in the car to not read correctly.

 

[slacktide_bitog]

Use the cheapest 5w30 on sale and run it to the OLM-suggested OCI

Is Napa synthetic on sale in Canada? Down here, it's only $2.99/qt. Most synthetics, and some blends, meet dexos standards.

 

[squatchy]

Originally Posted By: slacktide_bitog
Use the cheapest 5w30 on sale and run it to the OLM-suggested OCI

Is Napa synthetic on sale in Canada? Down here, it's only $2.99/qt. Most synthetics, and some blends, meet dexos standards.


Napa Synthetic does go on sale. Currently, the price is approximately USD $3.96/qt with the exchange rate. I snagged some Pennzoil Platinum with the $2/litre off rebate. Came out to approx USD $3.08/qt which is pretty good I think. Engine is humming nicely after the change - I'm surprised that there's a noticeable sound difference after switching to a synthetic.