Free boat! The trailer is the real prize. So even if the boat is worse than expected Ill have a great bonfire
What did you do to your GMT today? [Part II]
- Thread starter Mooseman
- Start date
My wife tells me that the AC in the Trailblazer has died. Last year she says it was weak but we never really drove anywhere with it so never noticed.
Well no cold air. Fan works, checked fuses and swapped relays. Nothing. Did a rip down the road to increase airflow, no dice. Jumped low pressure switch.... no dice. Clutch is not engaging. So over the next few days I'll dig in further as I read into the system more.
Well no cold air. Fan works, checked fuses and swapped relays. Nothing. Did a rip down the road to increase airflow, no dice. Jumped low pressure switch.... no dice. Clutch is not engaging. So over the next few days I'll dig in further as I read into the system more.
If clutch itself is burnt, there is a kit available with just the clutch if the compressor itself is healthy.
A/C Clutch Kit from AliExpress
A/C Clutch Kit from AliExpress
Rather than wait for RA to send the missing exhaust valve stem seals I went to the local dealership and bought the kit. Yeah, it was nearly double the price but at least I was able to start working. Temps are 10-15degF lower than normal so I opted for comfort over cost. First couple of seals, both intake and exhaust, showed significant wear when compared to the new AC Delco OEM replacements. Had a little excitement when one of the valve keepers jumped and I could not find it right away; subsequently found it so all now good.
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Bumper fascia was long overdue to be secured better on mom's TB. Years ago an impact left the bumper fascia hanging on the driver side, and loose on the passenger side. She had her handyman do a quick fix with a couple of stainless self tapping screws on each side. It's held all this time, but the gap on the driver side was over an inch, and everything was loose.
Removed it. Fashioned a replacement brace for the driver side, added some screws to the underlying plastic mounting point that's near each turn signal to eliminate their wobble. Reinstalled, tightened everything, and now we're good.
brace missing (at red arrow)
passenger side brace
driver side homemade brace
kind of visible, not a big deal
straight and firmly secured, gaps look good now
Removed it. Fashioned a replacement brace for the driver side, added some screws to the underlying plastic mounting point that's near each turn signal to eliminate their wobble. Reinstalled, tightened everything, and now we're good.
brace missing (at red arrow)
passenger side brace
driver side homemade brace
kind of visible, not a big deal
straight and firmly secured, gaps look good now
Attachments
Finished replacing the valve stem seals. Called it quits for the day just as the happy hour gong sounded; will button everything back up tomorrow. Out of curiosity, I compared the old vs. new seals using a go/no-go test with drill bits. The new seals were a firm go at 19/64" (.2968") and no-go at 5/16" (.3125"); the old seals were a loose go at 5/16" (.3125") for a difference of at least 1/64" (.0156"). The new seals have a lip at the inner edge of the seal face that wipes against the valve stem; that lip was gone on all of the old seals. Time will tell if this is the root cause of the oil consumption.
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Blckshdw
Moderator
CEL came on solid during the evening commute. I was dreading a P0305 again, but there was no hesitation or missing. Pulled up Torque at a red light to see this... 
I know I had replaced my IAT years ago, and I wanna say it's an aftermarket from AZ or something. Pulled up the live data and the temp readings were all over the place. HU wouldn't record, so waited until after I got home to record from my phone. Video was taken after the truck was parked for an hour, so that's why the coolant temp isn't at closed loop.
When I unplug the sensor, temp drops to -40 and stays there, so a new OEM IAT has been ordered.
I know I had replaced my IAT years ago, and I wanna say it's an aftermarket from AZ or something. Pulled up the live data and the temp readings were all over the place. HU wouldn't record, so waited until after I got home to record from my phone. Video was taken after the truck was parked for an hour, so that's why the coolant temp isn't at closed loop.
When I unplug the sensor, temp drops to -40 and stays there, so a new OEM IAT has been ordered.
CEL came on solid during the evening commute. I was dreading a P0305 again, but there was no hesitation or missing. Pulled up Torque at a red light to see this...
View attachment 108293
I know I had replaced my IAT years ago, and I wanna say it's an aftermarket from AZ or something. Pulled up the live data and the temp readings were all over the place. HU wouldn't record, so waited until after I got home to record from my phone. Video was taken after the truck was parked for an hour, so that's why the coolant temp isn't at closed loop.
When I unplug the sensor, temp drops to -40 and stays there, so a new OEM IAT has been ordered.
I would check all associated wiring and terminals for a loose or mildly corroded connection.
Blckshdw
Moderator
Yep, did check the wiring, nothing burnt or melted, although the loom had seen better days and that section coming off the coil pack bundle will need to get replaced. Connection was pretty solid when disconnecting and reconnecting the pigtail.
Truck seems to still drive fine, although my MPGs took a hit on this tank. I thought it may have been because I ran the AC during a few evening commutes, which I don't usually do. But if the air temp readings have been all over like this, I'm sure the PCM has felt like a frustrated parent with a bad ass child running around.
Blckshdw
Moderator
New OEM IAT sensor (on the right) showed up today, popped it in and temps held steady as you'd expect. Almost time to fill the gas tank, so will be interested to see if my MPGs improve before the next time. 
northcreek
Member
Replaced the fuel filler assembly on the Nox. (Hard to believe that a 2015 could get this rusty) trying to chase down the cause of the PO442 code. Couldn't find any leaks pressure testing but, it probably would have leaked soon. Couldn't believe "made in USA"... 
The TB developed the usual noise in the front left. So ordered and got a hub from work. Once it came in, turned out to be an ACDelco Advantage. Took it anyway as the noise is pretty bad. And as luck would have it, my manager let me go early today because this week was a shit show, despite being only 4 days long, and I pretty much kept our dept going.
So got home, jacked it up and confirmed the noise:
I won't bore you with pics of the hub job however it did take me only 35 minutes from jack up to jack down.
However, during that job, found something else that will need attention:
Looks to be the low pressure return line however I will replace both. In the meanwhile, I put some 75w90 gear oil, as recently suggested in another thread, to slow down the leak until I can get it done. It did quiet down the pump.
So got home, jacked it up and confirmed the noise:
I won't bore you with pics of the hub job however it did take me only 35 minutes from jack up to jack down.
However, during that job, found something else that will need attention:
Looks to be the low pressure return line however I will replace both. In the meanwhile, I put some 75w90 gear oil, as recently suggested in another thread, to slow down the leak until I can get it done. It did quiet down the pump.
Driving the Sierra to work today, got a low pressure warning on the RR tire. It was low but not dropping. Got it into the shop and there was a nail. Patched up fine. Good thing I found this out before the weekend and able to get it done at work for half price. Love this aspect of working at a dealership
I also ordered a tranny cooler thermal bypass "bypass" for the Sierra. The tranny runs a bit on the hot side, especially anytime while stopped. This will provide continuous full flow of fluid to the cooler. And if that doesn't cool it enough, I'll add fans to the 4"x33" cooler or add an aux cooler with fan. PPE also has a beefier cooler to replace the stock one but dang! it's expensive. I'll try other stuff first.
I also ordered a tranny cooler thermal bypass "bypass" for the Sierra. The tranny runs a bit on the hot side, especially anytime while stopped. This will provide continuous full flow of fluid to the cooler. And if that doesn't cool it enough, I'll add fans to the 4"x33" cooler or add an aux cooler with fan. PPE also has a beefier cooler to replace the stock one but dang! it's expensive. I'll try other stuff first.
northcreek
Member
In chasing down the PO446 or better said throwing parts at it. I believe I found the culprit. Did a forensic on the replaced Purge sol/valve and found a ruptured valve membrane. Even with all the parts still only about $150.00 and some swearing.
Matt
Member
- Dec 2, 2011
- 3,974
If it doesn't involve swearing, did you actually do anything?
northcreek
Member
northcreek
Member
Funny thing about this hunt/repair was that my wife started micro managing by saying things like “don’t put the new part in yet, let’s see how long it takes for the cel to come on”. Reminded me of the Seinfeld gas gauge episode with Kramer…lol
Hoping to pull the Envoy into the garage to reset the blend door motor. It was operating correctly, and its new last year, than I reset the battery, and it started clicking. I am thinking I installed it incorrectly, and never did a Recalibrate of the HVAC. And then when the battery got pulled, it auto-recalibrated.
flyboy2610
Member
I replaced that on my wife's '06 TB last year when I had it torn apart to replace the valve cover gaskets. She'd been getting a CEL for emissions, and since the part was right THERE I replaced it.