AC Whine?

[BG1988]

Have you confirmed that it is the compressor bearing, and not the tensioner pully bearing?

it's an industrial High voltage 360vDC electric compressor, it can also be the hamster wheel too.. No clutch

special install instructions are needed one misstep and it will COST $10,000 to replace the entire system....( one mistake and the whole a/c system will need to be replaced)

 

[BG1988]

That's exactly what it was. The eco-mode lifters failed in Cyl 8. They tried to do a top overhaul but it failed about three months later. It is an aluminum LS so it's not quite as robust as the steel case V8s. Does AutoStop work when you turn off 4cyl mode with hptuners? Honestly, I'd rather keep that - it's the only thing that lets me get a reasonable MPG - especially when my wife drives it in M4 all the time

i'm still getting 22.5mpg IN V8 mode around town on 12 year old worn out batteries royal purple improved it quite a bit (suspect clogged injectors) as my fuel trims were hella high positive +16-18 range.... dumped two cans in it then ran it 170 miles it's between 0-7 now which is normal range..

i was barely getting 9-13mpg that is a nice bump to 22.5mpg

I use the range technology They calmed it did not work but it does work with the hybrid model.... Make sure the 12v battery is connected good other wise the shift points are off for Super OVERDRIVE i.e 40mph 6th gear "EVT mode" 1,000 rpm would be about 48mph (I used battery shims)


Yes auto stop still works'


i'm reconditioning my batteries by driving it everyday like 12 miles aday but i plan to get the lithium battery upgrade


https://projectlithium.com/products/gm-tahoe-hybrid-lithium-upgrade-pack-20-blocks

 

[BG1988]

Yeah - I know it's an electric drive compressor, but I have read that it mounts similar and in the same place as the engine driven pump. I can handle the whine. Truck is on its last legs, but it ain't gonna be cheap to replace.



So - I had to replace the engine about 4-5 years ago. I replaced the Hybrid battery just before that with a Greenbean. Was initially happy with them, but when the replacement started faltering, they refused to replace it under the tiered warranty because the Tahoe doesn't have battery life messages on the info screen or check engine light. That was when it was $1500 to replace. Now it costs over $3k. The only real symptom I have is that it lunges when it's transitions to/from auto stop. It totally went away for about two years after I got the battery. Now, I shift in and out of M if I'm city driving. Wife only drives it in M (getting a whopping 13mpg). I drive in "D" when on the highway. I still get around 20 mph when i baby it.

use some royal purple I was getting 9-13 now it's 21-22.5 mpg that is with the 12 years old battery 107k exactly 35mph you can get like 22+mpg... just try and time the lights and use google maps to find an optimal route with less traffic and posted signage or lights..

see my fuelly log

HyHoe (Chevrolet Tahoe) | Fuelly

even in 100% M4 it should be about 17-19mpg as you don't have the super OD, if it's not obvious it's a whole another issue

the best I had ever done was 32mpg... on longer 170 mile trips about as good a Toyota corolla

 

[dnt1010]

Lithium battery upgrade sounds interesting, any Links that you could provide? Not seeing anything on my initial google search here.

 

[BG1988]

Lithium battery upgrade sounds interesting, any Links that you could provide? Not seeing anything on my initial google search here.

GM Tahoe hybrid battery pack - 20 blocks

V3 pre-orders will be fulfilled within 1 month Say goodbye to the old and refurbished NiMH battery, replace and upgrade to the award winning NexPower battery pack with better performance and affordable price. This NexPower battery pack with 20 V3 GT blades in reverse will fit the following...

projectlithium.com

also the A/C whine or noise is normal from what i have been reading should not be able to hear it in the cab with it going though, outside of the cab is normal


Air Conditioning The Two-mode Hybrid SUV's have no belt drive air conditioning (A/C) compressor. Instead, there is a 300V A/C compressor that bolts into the same location as a standard belt-driven A/C compressor. The A/C compressor includes a high-voltage A/C pump and an inverter module that converts 300V DC from the APM into 300V 3-phase alternating current. The A/C compressor is serviced as a unit, and uses POE (Polyol Ester) refrigerant oil instead of PAG (Polyalkylene Glycol) because it is less hygroscopic. The purpose of using an electric air conditioning compressor instead of a belt driven compressor is to provide air conditioning performance while the engine is in auto-stop. The A/C compressor features a high RPM scroll compressor that is pulse width modulated. During conditions with high ambient temperatures and high humidity, the driver may notice a unique high-pitched sound from the compressor. This is considered a normal characteristic, and it will be heard most noticeably in auto stop mode with the window lowered
8th page down

https://testing-public.carmd.com/Tsb/Download/115351/2713742