2005 GMC Envoy - 100K Maintenance Questions (long post)

[POW]

Very glad I found this site! I just received my Haynes manual in the mail (any good?) & am downloading the Service manuals as I type this.

I have a 2005 GMC Envoy. I bought it Certified Used from a dealer at about 67K miles. I was 21 years old (3 yrs ago), the dealership had some xxx # point inspection it passed & to be honest it hasn't had any major issues since I purchased it. All I have done is routine oil changes, oil filters, & tire rotations. Will need to check to see (if I can find) what other, if any, repairs were done before I purchased.

I am now approaching 100K miles. I have a wife & a baby daughter & all of our vehicles are paid for & I want to run this truck as long as possible, so I have started paying more attention to the vehicles as well as trying to teach myself how to do some of the maintenance myself. I am not the most mechanically inclined person but not afraid to try to learn. My dad was a great man but he was not handy at all, therefor I never took much of an interest myself until now!

At 95K I switched to Mobil 1 High mileage & started performing the oil changes myself, replaced air filter (K&N filter), & put on four new General Grabber tires.

Current issues/concerns:

• Check engine light has been on/off for last year or better. Always showing P0128 code (thermostat).
• Once the new tires were put on (Discount Tire), I started hearing sort of a humming/whinning from front end, at first I just thought it was road noise from new tires & didn't think much of it, I finally got smart & realized it adjusts w/ speeds & now believe it is either due to front differential fluid needing to be changed/replaced, or need a new wheel bearing (I believe Right front side). Those the first two things to check?

Here is a list of what I am planning on doing at 100K, would like feedback on what I am missing:

• All fluids flushed & replaced. (Transmission, coolant, brake fluid, power steering fluid, transfer case fluid.)
• Replace spark plugs (already purchased AC Delco 41-103 Iridium plugs)
• Clean Throttle Body
• Oil/Filter Change
• Tire Rotation
• Replace 02 sensor
• Replace/add front differential fluid

I am just starting to take a real interest in doing maintenance myself, my brother-in-law is pretty mechanically inclined & works on his cars, but he is going to be living out of state for the next 3-4 months. I barely have any free time as is & what I don't want to do is get in over my head & then be stranded without a running car or cost myself a lot of extra money. I want to pick a few things to start with & build my confidence up, I have a couple recommendations of quality local mechanics that should be reasonably affordable. I will also look to pick up parts & fluids myself & just pay the shop labor.

I am planning on doing next oil change, spark plugs, clean TB, & front diff on my own. If I need a new wheel bearing I think I might pay someone to do that as well as new thermostat (hoping new thermostat fixes P0128 code, need new inspection sticker in a couple months). If my BIL was around to help I would probably try to tackle those on my own... Is 02 sensor a good idea, can I do that on my own?

What would be reasonable rates/labor hours charged for following?

• All fluids
• Thermostat replacement
• Wheel bearing replacement

What else am I missing? Will check hoses/belts.

Sorry for the long post, but really appreciate any help.

Thanks!

 

[RayGumm]

Welcome to the Nation!!

Only thing I would add is rear diff fluid, but I am sure some more senior members will chime in if you missed anything else.. Also make sure to use ONLY Auto-Trak II in your transfer case. ANYTHING ELSE WILL KILL IT POST HASTE. Auto-Trak II is sold at many O'reilly's, NAPA, and GM Dealers, as well as online. Usually runs in the $7-$12 range, cheaper than the syn gear oil you will use for your diffs.

As far as tackling these things yourself, look them up on YouTube. A really cool member here, MAY03LT, has several videos on many of these things. Your Haynes/service manuals will help, too (haynes will be better for the beginner as it kind of dumbs down everything, but also can leave out important stuff, so do your research first.) Always read through the entire process for removal and installation of any part or fluid you plan to change out BEFORE you start. This will help you determine if you have enough time, experience, the right tools, etc. beforehand. Otherwise you might find yourself with a half disassembled something-or-other and realize you don't have the right tool, and the wife has the minivan at the mall... you get the picture.

A good labor rate will change depending on where you are, I have seen them as low as $75/hr at a shade tree mechanic in Wnchester, VA all the way up to $140/hr at a Subaru dealer in Fairfax, VA. They will more than likely charge the same labor rate for everything they do. Midas (which is hit and miss, my favorite and least favorite shops are both different Midases) will actually quote you a price for a specific job over the phone, and except for electrical diagnosing will not 'start a clock'. They will charge you the labor they quoted, even if it takes longer than the quote allowed. Some will allow your own parts/fluids, some won't. Ask. Some also charge a higher labor rate if you supply the part, which I consider to be a bunch of BS. ALL of them will have NO labor warranty if you supply your own part.

All that being said, as a member here, I would feel 100% confident tackling pretty much any job besides internal engine and transmission workings with little to no experience. These guys WILL help you and will ALSO warn you of things you may not want to tackle given your experience/confidence level. But if you do, expect walkthroughs and pointers along the way. You are in good hands.

Good luck, sir!

 

[Texan]

Welcome to the neighborhood. I grew up in the Houston area, but live in the DFW metroplex. My Dad was very handy, but never read instructions. I tend to be just
the opposite. Been a amateur gear head all my life. My TB is two wheel drive, so I do not have any experience on the 4x4 set up, but you will find a lot of good
information here. One item that seems important is to remove the fill plug before you remove the drain plug on the diff's and transfer case. Another item is if the
spark plugs have water or oil in the hole they are in, soak it out before you remove the plug. I have a plug socket that has a rubber insert in it that grips the plug that
works for me. Some people have had a problem with the plug porcelain breaking and falling into the cylinder. Do not let that happen. Good luck, and you will find
a lot of help at this site.

 

[The_Roadie]

You're getting good advice, but I have to ask why are you deferring the P0128 thermostat repair? It makes the engine run extra rich, costing you some mileage that could cost hundreds of $$ over the space of a year. And the excess fuel burns in the catalytic converter, overheating and clogging it over time, and that can also cost you performance, and again, $$$$ when you have to replace it. I've said for a long time that putting off a P0128 repair is misplaced frugality.

On the other cost question, you really don't care what the labor RATE is, but you want to get quotes from local folks (an independent GM-specialist mechanic is what I use for stuff I don't have time or the inclination to do). On an internet forum, our guesses aren't valid for your own neighborhood.

And honestly, we enthusiasts do so much ourselves that many of us have NO IDEA what a shop would charge because we shun shops to do the simple stuff.

 

[Wooluf1952]

Welcome

In case you haven't heard:
http://gmtnation.com/forums/topic/218-welcome-to-gmtnationcom-heres-the-story/

I may have missed it, but your 2005 doesn't have a rear diff drain plug. You'll need to remove the cover to drain it. You should be able to re-use the gasket.

 

[POW]

Welcome to the Nation!!

Only thing I would add is rear diff fluid, but I am sure some more senior members will chime in if you missed anything else.. Also make sure to use ONLY Auto-Trak II in your transfer case. ANYTHING ELSE WILL KILL IT POST HASTE. Auto-Trak II is sold at many O'reilly's, NAPA, and GM Dealers, as well as online. Usually runs in the $7-$12 range, cheaper than the syn gear oil you will use for your diffs.

As far as tackling these things yourself, look them up on YouTube. A really cool member here, MAY03LT, has several videos on many of these things. Your Haynes/service manuals will help, too (haynes will be better for the beginner as it kind of dumbs down everything, but also can leave out important stuff, so do your research first.) Always read through the entire process for removal and installation of any part or fluid you plan to change out BEFORE you start. This will help you determine if you have enough time, experience, the right tools, etc. beforehand. Otherwise you might find yourself with a half disassembled something-or-other and realize you don't have the right tool, and the wife has the minivan at the mall... you get the picture.

A good labor rate will change depending on where you are, I have seen them as low as $75/hr at a shade tree mechanic in Wnchester, VA all the way up to $140/hr at a Subaru dealer in Fairfax, VA. They will more than likely charge the same labor rate for everything they do. Midas (which is hit and miss, my favorite and least favorite shops are both different Midases) will actually quote you a price for a specific job over the phone, and except for electrical diagnosing will not 'start a clock'. They will charge you the labor they quoted, even if it takes longer than the quote allowed. Some will allow your own parts/fluids, some won't. Ask. Some also charge a higher labor rate if you supply the part, which I consider to be a bunch of BS. ALL of them will have NO labor warranty if you supply your own part.

All that being said, as a member here, I would feel 100% confident tackling pretty much any job besides internal engine and transmission workings with little to no experience. These guys WILL help you and will ALSO warn you of things you may not want to tackle given your experience/confidence level. But if you do, expect walkthroughs and pointers along the way. You are in good hands.

Good luck, sir!

Thank you, RayGumm! I actually found this site by watching one of MAY03LT's spark plug replacement video, he had a little icon that popped up that said follow me to GMTnation. Whenever I googled something regarding my envoy I always googled it and then put Trailvoy at the end, but always wondered about how inactive that site was & due to the non-user friendly site I never even bothered to register over there, so glad I found this site. I am planning on calling all around and visiting a few shops to get some quotes. While I wish I could just tackle everything myself, I don't ever have a full day to mess around & being stranded is what I am afraid of. I am 24 years old now, I plan to continue to take interest in my vehicles & maintenance, but for now, I don't want to bite off more than I can chew & discourage myself, as much as everyone here is opposed to contracting work out, I am okay with that. I want to be at least knowledgeable about the repair going into it, whether I am doing it myself or not.

Welcome to the neighborhood. I grew up in the Houston area, but live in the DFW metroplex. My Dad was very handy, but never read instructions. I tend to be just
the opposite. Been a amateur gear head all my life. My TB is two wheel drive, so I do not have any experience on the 4x4 set up, but you will find a lot of good
information here. One item that seems important is to remove the fill plug before you remove the drain plug on the diff's and transfer case. Another item is if the
spark plugs have water or oil in the hole they are in, soak it out before you remove the plug. I have a plug socket that has a rubber insert in it that grips the plug that
works for me. Some people have had a problem with the plug porcelain breaking and falling into the cylinder. Do not let that happen. Good luck, and you will find
a lot of help at this site.

Thank you for the tips, Texan! Spark plugs will definitely be the most "advanced" repair/replacement I will have worked on but I don't think I will have a problem with it, lots of good information on this site to help me out.

I am originally from Minnesota, born & raised, but spent 4 years in undergrad in North Carolina, after I graduated received some job offers here in Houston, & have been here the last 4 years. I love it here in Texas though and my wife is a diehard Texan. We don't plan on leaving due to the strong job market and low cost of living.

You're getting good advice, but I have to ask why are you deferring the P0128 thermostat repair? It makes the engine run extra rich, costing you some mileage that could cost hundreds of $$ over the space of a year. And the excess fuel burns in the catalytic converter, overheating and clogging it over time, and that can also cost you performance, and again, $$$$ when you have to replace it. I've said for a long time that putting off a P0128 repair is misplaced frugality.

On the other cost question, you really don't care what the labor RATE is, but you want to get quotes from local folks (an independent GM-specialist mechanic is what I use for stuff I don't have time or the inclination to do). On an internet forum, our guesses aren't valid for your own neighborhood.

And honestly, we enthusiasts do so much ourselves that many of us have NO IDEA what a shop would charge because we shun shops to do the simple stuff.

Thank you, Roadie for your reply. To be honest, everything I have read about the thermostat repair made me believe it wasn't an urgent repair. That is my fault for being ignorant and not truly looking into the effect it could have on my vehicle. Like I said, I haven't been as proactive with my Envoy in the past as I am hoping to be going forward.

I am going to do some research in my area to select a handful of quality shops, and look to get quotes from all of them. While I hope to become an enthusiast myself & do all of the work, like I said in the OP I don't want to bite off more than I can chew at once & screw things up. I have virtually no experience working on cars at all and with my BIL being away for the next 4 months I am a little hesitant to try and tackle too much by myself.

Thanks again for the reply, I am going to look into clearing that P0128 code much quicker.

Welcome

In case you haven't heard:
http://gmtnation.com/forums/topic/218-welcome-to-gmtnationcom-heres-the-story/

I may have missed it, but your 2005 doesn't have a rear diff drain plug. You'll need to remove the cover to drain it. You should be able to re-use the gasket.

Hello Wooluf, thanks for the link! Very interesting. I always wondered about Trailvoy, while that site did help me out with a few items I always was curious about how much content was over there but how inactive the site was, very glad I found GMT nation!

Thanks as well for the tip on the rear diff!

 

[Mounce]

Welcome! You've definitely came to the right place.

Idk if you knew it or not
but the transfer case fluid is supposed to be changed every 50k. Hopefully it got done by the previous owner even 50k rolled around.

 

[Mark20]

Welcome aboard. You've found where the enthusiasts hang out and we're more than willing to help. Even rescue you from the middle of nowhere and crank a wrench.

If you're going to replace the coolant you might as well replace the thermostat and coolant temp sensor. Just check the temp sensor. GM put way more than needed teflon tape on the threads on mine. Two wraps max. There's a suggestion on here on how to cut a standard deep socket to let it fit over the wire pigtail on the sensor. That will make your life much easier. Also a 15mm flex head stubby ratchet to get at the bottom alternator bolt.

You may want to consider replacing your serpentine belt, idler on it and tensioner. Also the CPAS.

One thing to also consider is a good quality tool set. The TB & Voy are metric. (All new US designs went metric around 1993.)

 

[qsp01]

What is your temperature gauge reading? The thermostats change is pretty straight forward and can be easily done in an afternoon.

 

[KNBlazer]

Bandaids of all sizes!!!

 

[KNBlazer]

if possible try sticking with AcDelco parts... the majority of the time, you get a better deal buying AcDelco online over buying aftermarket from your local auto parts store...

 

[POW]

What is your temperature gauge reading? The thermostats change is pretty straight forward and can be easily done in an afternoon.

Thanks for everyones replies! Sorry for the delay. Temperature gauge stays pretty steadily right around the 210 mark, I will keep a closer eye on it. Forgot to add the CEL does go on and off periodically, but mainly is on. Do you recommend removing the alternator or no? Are there any good video tutorials out there for thermostat change?

Welcome! You've definitely came to the right place.

Idk if you knew it or not
but the transfer case fluid is supposed to be changed every 50k. Hopefully it got done by the previous owner even 50k rolled around.

Thanks for that reminder.

if possible try sticking with AcDelco parts... the majority of the time, you get a better deal buying AcDelco online over buying aftermarket from your local auto parts store...

Yes, the spark plugs I just purchased were AC Delco. Will remember that for future parts. Thanks.

Welcome aboard. You've found where the enthusiasts hang out and we're more than willing to help. Even rescue you from the middle of nowhere and crank a wrench.

If you're going to replace the coolant you might as well replace the thermostat and coolant temp sensor. Just check the temp sensor. GM put way more than needed teflon tape on the threads on mine. Two wraps max. There's a suggestion on here on how to cut a standard deep socket to let it fit over the wire pigtail on the sensor. That will make your life much easier. Also a 15mm flex head stubby ratchet to get at the bottom alternator bolt.

You may want to consider replacing your serpentine belt, idler on it and tensioner. Also the CPAS.

One thing to also consider is a good quality tool set. The TB & Voy are metric. (All new US designs went metric around 1993.)

Thanks for the tips & suggestions, I will keep that all in mind when I figure out everything I am going to do/attempt to do. Have most of the needed tools.

 

[triz]

The fluid changes are pretty simple, even for the novice mechanic. I would think you could knock all the diffs and transfer case out in just a few hrs. For the transmission you either will need more time or pay to play.

I just did mine today and I was lucky enough to have a friend with a flush machine. So much simpler and not very messy.

At 100k I would do both diffs, transfer case as well as transmission. Coolant and definitely brake fluids. I 'll the PS fluid up to you.

 

[qsp01]

If you ECT is getting to 210 then the theromstat is probably closing ... how long does it take to get to 210 on the guage? Some people are able to get to the bolt through the wheel well but I wasn't able to for the one bolt. I had to remove the bolt holding the alternator but just slid it forwards with out disconnecting any of the wires to the alternator. A short open end wrench helped to get at one of the bolts that is up against a tube although when I was bolting the alternator back up I ended up slightly bending the tube away from the alternator. Here is a description of P0128:


- Doug

DTC P0128

CIRCUIT DESCRIPTION
An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control and as an enabling criteria for some diagnostics.

The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the regulating temperature of the thermostat, diagnostics that use ECT as enabling criteria may not run when expected.

This DTC will only run once per ignition cycle within the enabling condition. If the PCM detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0128 Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature

CONDITIONS FOR RUNNING THE DTC

* DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0335, P0336, P0351-P0356, P0442, P0446, P0452, P0453, P0455, P0480, P0496, P0502 and P0503 for automatic transmission only, P0601, P0602, P0604, P0606, P0621, P1133 are not set.
* The ECT is less than 75°C (167°F) , but less than 70°C (158°F) .
* The intake air temperature is more than -7°C (+19°F) .
* The engine is running between 30 seconds and 30 minutes .
* The vehicle has traveled more than 2.4 km (1.5 mi) at more than 40 km/h (25 mph) .
* The mass air flow (MAF) calculated is more than 15 g/s .
* This DTC runs once per ignition cycle when the above conditions are met.

CONDITIONS FOR SETTING THE DTC

* The calibrated amount of engine run time has been met
* The calibrated amount of engine air flow has been met
* The calibrated vehicle speed and distance have been met.
* The calibrated ECT of 80°C (176°F) has not been met

ACTION TAKEN WHEN THE DTC SETS

* The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC

* The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.

 

[POW]

Alright, a few more questions.

• Last couple oil changes I have done I have used the Mobil Super (high mileage conventional). Right now, doing them every $5K miles. Should I switch to full-synthetic? If I do, what is the recommended time interval (miles) between changes? Here is the oil filter I use.. http://www.amazon.com/gp/product/B004D5LAFC/ref=ox_ya_os_product_refresh_T1 . Is this alright?
• Can anyone link me the best/most appropriate wheel bearing I should order? I am confident that it is the front-right wheel bearing that needs to be replaced.
• Can anyone link me the best/most appropriate thermostat replacement?
• Also, this may be a real newb question, but me jacking up the front end to get underneath for the oil changes, will the car being uneven create any draining issues when doing the oil change? Should I jack up the back end as well so that it is level or am I just looking to make things more difficult. I've always just jacked up the front & used 2 jackstands, if I do the back, will a rear-centered 3rd stand be sufficient or should I try to have 2 in the front & 2 in the back? I have 4 jack stands, the two I always use are 3.5 ton & I believe the others are as well but have to double check.

I will just use this thread for all of my questions. Appreciate everyone's help.

 

[Mark20]

I went with Amsoil OE at about 75K miles. I first put a new filter on and ran a bottle of their Engine Flush through. Just let it idle for 10 or so minutes. Then a normal oil change using Amsoil and a Wix filter. I've just been following the oil life monitor changing it with around 5 - 10 % left.

IIRC what I've read on Bob is the Oil Guy, the Mobil filters are fine. You can probably find a cut it open review on YouTube.

I us ACDelco T-stat and temperatuer sensor ordered through Amazon.

I think you'll leave about a pint of old oil in the pan since the drain is at the front. I just squeeze under, unbolt the skid plate and go to work. The filter is a little "fun" to reach but you can get it done with all wheels on the ground.

 

[The_Roadie]

...what is the recommended time interval (miles) between changes? ...

The vehicle comes with a built-in Oil Life Monitor system. The vehicle will tell you when it's time to change the oil, and the system keeps track of how you drive it and the engineers (in this case) went to some trouble to try to SAVE the owner money. It's typically around 10K miles.

Is there any compelling evidence you have that the OLM can't be trusted? The 3K intervals still touted by the quickie-lube places are self-serving lies. All lies.

 

[POW]

Thanks. Yeah, I used to just stick to 5K miles with dino, but I just picked up the Mobil 1 full-synthetic 5w30 & planning on changing it tonight. Was reading about best way to transition to synthetic but I am planning on just switching all at once & then changing the filter again in 3-4K miles & probably doing another full oil change around 40-50% & then follow the oil life monitor from there on out.

Anyone strongly object against this approach?

Thanks.

 

[POW]

Another newbish question... Sorry - trying to learn!

When I go to do my plugs & throttle body, do I just need to pull the 10 & 28 fuses shown in Mayo3LT's video? I have read elsewhere to disconnect negative terminal but if that isn't necessary then I don't want to mess with it.. Otherwise, just planning on following Mayo's videos as instruction.

Thanks!