What did you do to your GMT today? [Part II]

Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
One possibility is that they changed suppliers since the last set, especially if both are the same. They don't make their own parts, they just rebox whatever parts they get. The best I've ever seen were the original GM parts. Oddly enough, the MAS, FVP and Dorman look like the originals, same for the fronts.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,027
Brighton, CO
I replaced the wheel seal on my XUV some months ago while Chasing a Vibration I replaced the wheel bearings and wheel seals... I must have dont something wrong, as the passenger side has been oozing since.

Going into winter, I dont want to be crawling under there every month to top off the diff, or god forbid, forget, and have to replace the diff.

So I got to re-replace the axle seal. I couldnt see anything wrong with the one I pulled out... Hopefully the new one doesnt leak.
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
I've had that happen on my 02. Replaced the seals and one leaked, getting all over the parking brake. I remember saving that shoe by soaking it in solvent and lots of brake cleaner.
 

Blckshdw

Moderator
Nov 20, 2011
10,654
Tampa Bay Area, FL
As mentioned in a previous post, I had noticed some battery issues after the EXT was parked for a few days. With a 4 year old battery, thought I may be due for a new one. Had gotten into the habit of throwing the charger on it overnight, when I new I had to go somewhere after being idle and that was working OK.

Here's a couple of screen grabs of the battery monitor when getting home after the evening commute, when I first noticed the problem, and after about a month of the 'Monday night' pre-charge routine. Somewhat of an improvement at holding a charge, but dropping this low after turning the key off was still a concern.

Screenshot_20231024_170957_Battery Monitor.jpgScreenshot_20231109_164936_Battery Monitor.jpg

So this weekend I decided to throw the charger on Sunday mid day, all day Monday, and pulled it off this morning as I needed to hit the grocery store for a few things. The graph looked the same as always before pulling the clamps off, but the voltage stayed at 12.8V instead of dropping to 12.5 immediately, and slowly going down to about 12.3. When I opened the driver's door and woke up some modules, it dipped to 12.5 but held steady.

Screenshot_20231121_102619_Battery Monitor.jpg


After the short round trip to the store, checked it again, and got a steady 12.6. She'll be parked for the rest of the day, but I've got some pretty lengthy drives ahead of me Wednesday and Thursday, over an hour 1 way, so I'll really get to see how the battery looks after some heavy usage by the amp, and then be parked for the weekend.

Screenshot_20231121_110826_Battery Monitor.jpg
 

Mike534x

Member
Apr 9, 2012
879
Received the new links from RA. I can't tell if this is a current or old batch/stock. Differences I noticed were the boxes says "AC Delco Professional", whilst the Amazon links are just in a white box with a AC Delco sticker and part nunber slapped on the end. But packaging wise, these are identical to the ones I've got on the Envoy.
 

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Mike534x

Member
Apr 9, 2012
879
Thermostat crapped out over the weekend on the TB (already knew it needed to be replaced), got the new one in and sits happily at 210. Temps ranging from 192-200 so its within spec now. Also replaced the battery, the previous owner had an autocraft in there from 2018. Snagged a Everstart Maxx 800CCA from Walmart last night, so that's one less thing off the list.

Oddly enough, when loading Torque it showed the first current fault to be the knock sensor (that I've been chasing down and assumingly fixed), but no check engine light. Right underneath was the pending P0128 for the Thermostat, and the only light on the dash was the "check gauges" one. Very strange.
 
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azswiss

Member
May 23, 2021
853
Tempe, AZ
Tackled the ball joint replacement job over the last couple of days. Everything was going as expected until I got to separating the lower ball joint from the knuckle. I was using a pickle fork so I knew that there would be some heavy smacking required but this went way beyond what I was expecting. After multiple sessions (I had to walk away, lunch, etc.) I had to conclude that something was not right.

I was using a HF pickle fork that I had used previously (& successfully) on my CJ7. For some reason, it felt as if the fork was bottoming out. On a hunch I checked the fork (now all beat to hell) against the new lower and, to my surprise, found that the width of the ball stud was larger than the separation between the fork tines. So, went back to Autozone, and picked up a loaner fork with wider tines (I already had the ball joint press & accessory kits from them).
20231130_151825.jpg

But . . . the wider fork also bottomed out, despite being wider than the ball stud!!!!

By now the grease boot was all gone so I checked the thickness of the fork tines and compared against the separation between the knuckle face and the control arm face. The problem was that the fork was not able to go in deep enough to fully engage the max thickness of the fork before bottoming out against the knuckle body.

I fabbed up a couple of spacers (1/4" total) to slip around the ball stud, slipped them in place, and after a dozen good shots the knuckle separated.
20231201_121814.jpg

From there, pressing out the old joints and pressing in the new was straightforward. Rinse & repeat on the other side (albeit a lot quicker).
20231201_122825.jpg

20231201_163527.jpg
 
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Blckshdw

Moderator
Nov 20, 2011
10,654
Tampa Bay Area, FL
Took a staged pic in front of it. :laugh:

20231212_111137_resize.jpg

Fresh oil, new filter, hit all the zerks with a few squeezes for good measure. Ever since I had that experience with a bad (probably wrong filter in the wrong box) my anxiety always shoots up for that first start after an oil change.

Noticed things were a little wet around the CPAS. Sprayed some degreaser and hit the areas I could reach with a scrub brush, will check again after a few drives and see if it's just that spot weeping down, or if I've got more issues to look into.
 

Ilikemy3s

Member
Dec 3, 2011
364
Knew for a little while the drivers side front axle shaft was on its way out along with various bushings needed to be replaced as well as a trailing arm. Planned to do them next week while on vacation. On way into work via I95 yesterday at 5 am i hit a nice sized unseen pot hole and that took something out as the clicking noise and steering told me it was probably the axle. Limped it to office as was closer there than home. Called the local shop to my work that I have used before (and that has discount rates for local businesses) and he was able to get me in .. Yup the axle left the building. So i asked him while he had it up in the air, could he do the other items. So while I was at, work, his crew was at work on my truck and ready by end of the day. While I was not planning on spending the $1k, I did not have to work outside, in the cold, on my days off and now I got peace of mind. She rides and steers better as well.
 

Ilikemy3s

Member
Dec 3, 2011
364
Ever since I had that experience with a bad (probably wrong filter in the wrong box) my anxiety always shoots up for that first start after an oil change.

How did you know it was a bad / wrong filter if it looked the same? Engine not right on start up ?
 

Blckshdw

Moderator
Nov 20, 2011
10,654
Tampa Bay Area, FL
How did you know it was a bad / wrong filter if it looked the same? Engine not right on start up ?

It was a Napa house brand filter that was on sale, it didn't 'feel' right when I spun it on. There's usually that snugness when the rubber seal meets the metal, and then you can tighten it from there. In this case it had a hard stop, like when something bottoms out. Like the radiator or oil cap does.

I thought it was maybe a different type of rubber seal, but it turns out it didn't seal at all. When I started the engine, fresh oil puked out everywhere. Tried to tighten it, no dice, wasn't until I reached all the way up blindly that I could feel a significant gap between the top of the filter, and where it was supposed to seal. Have been back on my Mobil 1 filters ever since.
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
Had that happen to me years ago with a Fram orange can of death (before I knew any better). This was on the GF's (now wife) 89 Civic CX. Figured it was just bad threads.
 
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northcreek

Member
Jan 15, 2012
3,295
WNY
I now check inside the filter box at the store, some cheap ass did a switcheroo on me at Wally World once.... :hissyfit:
 
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Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
Brought the TB in to the dealership to have the engine mounts replaced. I had already bought them but never got around to replacing them because of the usual 10Hz shake. Since it was now winter, I had no desire to do it in my driveway. It also has a leaky tire and a loose heat shield. Book time for the mounts is 2 hours. OK, not so bad. The advisor later told me it was taking longer because of everything that was rusty. Damn. Even later, he tells me the tech now has a no crank problem. Go to the shop and he shows me the main ground wire broke when he jacked the engine to replace the mounts. Started fine when he used a pry bar from the battery to the block. He was able to strip and put a new eyelet connector of the end of the cable. Tire leaked around the rim which was resealed and the shield was a quick fix with a sheet metal screw and washer.

Final bill came to $581. Would have been double without my employee discount! :eek: I would have endured the shakes for the winter but at least it's done and no more shakes. Happy wife.

Get home with it and now notice creaking when turning the steering. Will try to check that tomorrow. :frown:
 

Blckshdw

Moderator
Nov 20, 2011
10,654
Tampa Bay Area, FL
Took it to the hardware store to get loaded up with some goodies. Some 12' 2x4s, and 8 foot roofing panels. These are the times I'm glad I've got the EXT for that little extra room. ☺️

Threw some towels in the front to protect the dash, and the windshield just in case the lift gate went up came down hard enough to try and push everything forward. Bungee cord through the hitch, hooks in the latch to hold it down. Since it was mid day, traffic was light, and I took extra caution with the speed bumps in the neighborhood.

20231221_120650_resize.jpg20231221_120703_resize.jpg

Time to get her unloaded and back to work!

20231221_122527_resize.jpg
 

Mike534x

Member
Apr 9, 2012
879
I get to spend this weekend/Christmas replacing the thermostat again! Been driving the Trailblazer the last few weeks (knock codes gone!), and noticed something was off with the themostat taking ages to creep up into its cozy 210 mark. Get to a stop light, and it hits 210, step on gas and it drops a few notches....don't tell me. Open torque at the next stop light, she's hovering dead set at 190* light changes again and she drops to 180*. Ugh...400 miles and this AC Delco thermostat has failed. Explains the drops in the gas mileage again. Pulled into the gas station to get the ole feel test going, top hose is nice and hot. Bottom hose leading to the t-stat? cool. Yep....just what I wanted to do.

This is literally the third AC Delco branded thermostat that's failed within a short period of time. The one for the Envoy lasted 6 months, the replacement for the Envoy lasted 2 months, and now this one. I went Stant for the Envoy's 2 years ago and its been fine, unforunately, the "Stant" thermostats on Amazon are Motorad's in a Stant box.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,027
Brighton, CO
That sounds like a water pump or a clogged bypass to me... Maybe something else clogged too.

Thermostat should be cold all the time, or overheating all the time.. Not a mix of in the middle.
 

Mike534x

Member
Apr 9, 2012
879
That sounds like a water pump or a clogged bypass to me... Maybe something else clogged too.

Thermostat should be cold all the time, or overheating all the time.. Not a mix of in the middle.
I was wondering if there was a clog somewhere, the lower pipe does stay cool. It's just a matter of the temps fluctuating 10 to 15* F while driving/stopping, when it would stay pretty solid. It did hover and stay over 195 after the change. I'm so used to the way the V8 is.
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
Pulled into the gas station to get the ole feel test going, top hose is nice and hot. Bottom hose leading to the t-stat? cool.
Don't forget that these engines are reverse flow, in other words, the coolant flows from the engine through the top hose into the radiator, is cooled, and then moves back into the engine from the radiator lower hose through the thermostat.

Did you check the fan clutch? When moving, the inrush of air through the radiator is cooling it. My temp hangs around 190f steady. At 210f, the fan should be starting to pull air. With the inrush of cool coolant, yours might be dropping to 180f

How to test the electro-viscous fan clutch
 
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Mike534x

Member
Apr 9, 2012
879
TB is an 08, so it has the thermal clutch. The temp fluctuations happen after its been completely warmed up and driven for 30+ mins give or take. I noticed it when I had spent an hour driving to the next town.
 

Eric04

Member
Dec 3, 2014
392
West Michigan
Drove it about 160 miles round trip to snag some second hand Cruze wheels with snow tires to fit my Bolt. I had a p0136 code pop last Friday. Cleared it out before the trip and watched sensor data for a good 80 miles. Nada. Everything looked fine, so no return of the code yet. The old mule is still a nice expressway cruiser.
 

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Mike534x

Member
Apr 9, 2012
879
Got the winter wheels put onto the Trailblazer, gotta drop her back off because Discount Tire isn't balancing the wheels properly. Rear ones are still vibrating when going over 50.

Been having an issue with the ABS warning light popping on and off randomly on the Envoy, recently it's been staying on longer then the other lights during startup. Today it stayed on before shutting off, and back on a few times before staying off. Not sure if there's a flaky ground, or one of the speed sensors on the new hubs aren't registering properly. What a pain.
 

azswiss

Member
May 23, 2021
853
Tempe, AZ
After replacing the ball joints and rotating the tires I checked the alignment (toe & camber). 20240114_131259.jpg
20240114_131341.jpg
The front & back reference bars have identical pairs of notches that ensure the string is properly located. The jack stands are set to pass the string thru the center line of the wheels. For toe-in, I measure out from the fore & aft rim edges of the front & rear tires tire to the line.

20240114_134604.jpg

Measurements are then entered into an Excel spreadsheet to get the results.
Capture.JPG

Camber calculation uses a similar technique.
20240114_140334.jpg
Results: total toe-in was in spec (+0.1deg actual vs, +0.1deg to +0.2deg) whereas camber was slightly out of spec (+0.1deg,+0.2deg vs. +.25deg to +.50deg).
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
Changed the oil and filter in the Sierra after work. Was at 29% OLM, about 10k km on it. Did it all in my driveway at a balmy -5c. Still cheaper for me to get my oil from RA despite my employee discount at the dealership ($8CAD vs. $20CAD /qt. x 7). Also now using Wix filters. Just 80¢ more and way better than ACDelco, which seems to be made by Fram.

And every time I change the oil, the engine just quiets down. Could be real or psychological.
 

Mike534x

Member
Apr 9, 2012
879
What a week! The battery in the Envoy took a crap, and I'm 4 months outside of the warranty period. It's a Duracell AGM I got from Sam's Club in 2020, and it's only been 3 years! I planned to get another, but they've gotten pricey as of late. Paid $139 in Sept. 2020, and the same battery is currently $199 and some change. Only store that had it in stock was an hour away, so off to Wally world to grab the same Everstart I put in the TB.

Power steering return line on the Envoy decided to gush fluid out all over the strut tower when leaving work. Managed to make it home, despite the pump groaning. Ripped out the bracket/rubber grommet, and used the dremel to cut out about 4 inches of the old line. Slipped 3/8 fuel hose onto both ends, and snugged it with two worm gear clamps. I did find a small pin sized hole from where the rust made it through.

Downside is the fluid ate away at the woolwax, so I need to get that touched up again :crazy:
 

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mrrsm

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Hmmm... You might want to check out @Redbeard 's ACDelco Spark Plug Purchase Thread that went sideways...

 

Redbeard

Member
Jan 26, 2013
3,450
Put new ACDelco 41-103 plugs into the trailblazer today. Was surprised that they were not gapped correctly out the box.
The biggest hint these aren't original OEM plugs is that they need gapping. With irridium plugs one does not gap them because it can too easily damage the irridium. Of the irridium plugs I have purchased I checked them with a dial indicator and the true oem A/C Delco plugs were all within .001" of each other! As MRRSM suggested read over the counterfeit ACDelco plug thread to see the ways one can check if they purchased counterfeit plugs. It is frustrating that we have to look our parts this closely to see if they are fake.
 

Mike534x

Member
Apr 9, 2012
879
Finally got around to chasing the rear end clink/pop/bang. Sure enough, the rear sway bar links were shot. The way they both failed has me scratching my head, so upon removal I found the upper half of both links where they hug the frame bracket to be nice and tight, just like out of the box. The lower half had a ton of free play in the socket. So grabbing the link, and trying to twist it gave a false they're "good" test.

So roughly, I got 3 1/2 years out of the ACD Pro Links, which is only a hair longer then the Moogs from my experience so far. Bought them mainly because I liked the o-ring that holds the rubber boot in place, and that it came with locking nuts. But cost wise? I don't think they're worth it. At the time they were replaced, I spent $10-15 more on them vs the Moogs, but they didn't really last that much longer. So with that, I went back to Moog. Feels great having the rear end feel tight again at least.

Sway bar bushings looked good still, but I may swap those out for the polyurethane ones just to help really "firm" it up back there. Otherwise, she's been great, and haven't spotted a drop of power steering fluid either with that "fix" in place. :thumbsup:
 

Mike534x

Member
Apr 9, 2012
879
Trailblazer developed the "low oil pressure, stop engine"/check gauges warning a few days ago. Bought a new sensor off RA, sprayed some electrical cleaner on the connector and the warning is still on. Oils still full from the oil change, and left it idling for a few minutes and its quiet as can be. Ugh...time to do some searching. :hopeless:
 

mrrsm

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Oct 22, 2015
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If you hear the slightest Valve Train Clatter...Don't Risk Running The Engine... I posted some links recently for a similar situation that might be the source of this issue with the 5.3L Engines...with a possible solution as well... Found here:

 
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Mike534x

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Apr 9, 2012
879
If you hear the slightest Valve Train Clatter...Don't Risk Running The Engine... I posted some links recently for a similar situation that might be the source of this issue with the 5.3L Engines...with a possible solution as well... Found here:


I was contemplating purchasing a mechanical gauge for the interior, I found the mechanical one I bought from HF way back to test the pressure this weekend (while its still nice enough out). Thats what bugs me, the valvetrain is quiet....quieter then the 5.3 in the Envoy.

So this was odd, I came across a post on here from awhile ago where another user had the same issue. Their solution was disconnecting the battery for 30 mins, and that corrected it. Sure enough, I did the dreaded disconnect, and the warning/messages are gone and the dummy gauge is working. I cannot fathom how, or why that did anything.

Before doing the battery reset, I unplugged the switch and started the truck up. The gauge was still pegged at 0, with the warnings on. My understanding is that dummy gauge should still read 40 PSI with the switch unplugged, and it didn't. So this partially leads me to believe there's a grounding issue somewhere, or I have a small electrical short in the pigtail/harness perhaps.
 
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mrrsm

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Your observations are Real GOOD News... But as far as the *Dummy 40 PSI* Reading on the IPC...That ONLY applies in the case of the GM 4.2L LL8 Inline Six Cylinder Engine... but NOT for the GMT360s bearing the LS Motors...all of which have the Direct TRUE Oil Pressure reading coming out of the Driver's Side Upper Rear Oil Gallery Port where the TRUE Oil Pressure is actually being captured. Again the Filter Basket Nested Below is the Likely Suspect here because Collected Black Oil Sludge and "Mung" can block the Pressure panel inside of the Oil Pressure Sensor ...and obscure the correct readings. Have I got the right vehicle ID'd from your Profile here?
 
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Mike534x

Member
Apr 9, 2012
879
Your observations are Real GOOD News... But as far as the *Dummy 40 PSI* Reading on the IPC...That ONLY applies in the case of the GM 4.2L LL8 Inline Six Cylinder Engine... but NOT for the GMT360s bearing the LS Motors...all of which have the Direct TRUE Oil Pressure reading coming out of the Driver's Side Upper Rear Oil Gallery Port where the TRUE Oil Pressure is actually being captured. Again the Filter Basket Nested Below is the Likely Suspect here because Collected Black Oil Sludge and "Mung" can block the Pressure panel inside of the Oil Pressure Sensor ...and obscure the correct readings. Have I got the right vehicle ID'd from your Profile here?

Oh yes I replaced that little screen a long time ago on the Envoy. The issue with the oil pressure warning is what is currently affecting the Trailblazer with the I6 :yes:, sorry I should've specified that!
 

mrrsm

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Oct 22, 2015
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Okay, Mike... NP... So the outstanding issues and questions to be determined are:

(1) After installing an M16 X 1.5 X 1/4" NPT Adapter and Line leading to an Analog Oil Pressure Gauge...Do the Nominal Oil Pressure Readings fall into being at LEAST 12 PSI when @ an Idle of around 600-650 RPM ...and does the Oil Pressure also RISE to around 65 PSI @ around 3,000 RPM?

(2) If NOT...has the Gerotor Oil Pump Orange Gasket (or the Early Model "Blue" Viton "O" Ring) been Cut or Collapsed enough to cause a Loss of Suction & Vacuum into the Gerotor Oil Pump from the Oil in the Crankcase?

(3) Has the Oil Pump Pick Up Tube (Screen) become so blocked and occluded after ingesting too much Carbon Mung held in place on the Screen by Gas-Gum Lacquer forming from Engine Blow-By occurring in all LL8 High Mileage Motors? If the Dipstick bears a Heavy Odor of PURE Gasoline...it would be very symptomatic of having Trapped Low-Tension Compression Rings around all of the Upper Piston Lands & Grooves. An ACDelco TEC Solvent Treatment (Top Engine Cleaning) can help with this issue.
 
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Mooseman

Original poster
Moderator
Dec 4, 2011
25,177
Ottawa, ON
I'll bet that it is an issue with the throttle body and/or the PCM needing a reset. If the battery was disconnected and the TB wasn't cleaned, it will idle lower than normal and set off a low pressure warning as the threshold is about 12psi. Try cleaning the TB and disconnecting the battery for 30 minutes.
 

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