I have an annoyance in my 99 Yukon, and can not locate it.
Sounds like.....a cross between a wind/vacuum-kinda bearing/whine thingy, but then again it don't...?
Not present when NOT in A/C mode....
When in heat mode, I've run thru all speeds and all actuator door positions and cannot replicate the noise.
This would lead me to believe it must be connected to the A/C, or at least the increased torque on some rotating part when the compressor cuts on.
A stethoscope on the A/C compressor does not reveal the noise @ idle or acceleration in the drive way.
Vehicle is for around town, and long distance vacation travel...no off road, no abuse, 150,000 miles.
I've owned this 99 since 99, and replace the following because of age, and
in hope that one may be the culprit.
1) A/C compressor:
I replaced it when I opened the system earlier this year for a vacuum down and recharge.
2) Serpentine belt:
the old one was fine, it's now an emergency replacement item.
3) Idler pulley:
This was the second time I replaced this, thought it may be the noise.
4) Tension-er pulley:
pulley wobbled slightly....thought this was it, but..........no.
5) Blower motor:
Not the problem, but the new one is quieter, and pushes more air.
When replacing this I found very little trash behind the blower motor, cleaned it out, not the problem.
6) Transmission:
I had it serviced, filter/fluid change. Noise still present.
I'm beginning to suspect something to do with shifting, only because it don't seem to be easily identifiable else where.
As I type this......I realize it cant be Transmission if it don't do it in heat mode......so the circle continues.
This is what I know about the noise.
Not present @ idle
Starts @ very low acceleration.
Can be controlled with with a light on/off touch on the gas pedal.
I appears to change pitch thru a transmission shift??
I can initiate the noise or quite it with the gas pedal at slow/moderate speeds.
The common denominator appears to be 1500 rpm but it is not present @ 70+ mph @ 1700+ rpm.
So if it's not (presumably) one of the above..... What the hell is it?????
I'll believe almost any thing now, so any assist appreciated.
Ron.
Sounds like.....a cross between a wind/vacuum-kinda bearing/whine thingy, but then again it don't...?
Not present when NOT in A/C mode....
When in heat mode, I've run thru all speeds and all actuator door positions and cannot replicate the noise.
This would lead me to believe it must be connected to the A/C, or at least the increased torque on some rotating part when the compressor cuts on.
A stethoscope on the A/C compressor does not reveal the noise @ idle or acceleration in the drive way.
Vehicle is for around town, and long distance vacation travel...no off road, no abuse, 150,000 miles.
I've owned this 99 since 99, and replace the following because of age, and
in hope that one may be the culprit.
1) A/C compressor:
I replaced it when I opened the system earlier this year for a vacuum down and recharge.
2) Serpentine belt:
the old one was fine, it's now an emergency replacement item.
3) Idler pulley:
This was the second time I replaced this, thought it may be the noise.
4) Tension-er pulley:
pulley wobbled slightly....thought this was it, but..........no.
5) Blower motor:
Not the problem, but the new one is quieter, and pushes more air.
When replacing this I found very little trash behind the blower motor, cleaned it out, not the problem.
6) Transmission:
I had it serviced, filter/fluid change. Noise still present.
I'm beginning to suspect something to do with shifting, only because it don't seem to be easily identifiable else where.
As I type this......I realize it cant be Transmission if it don't do it in heat mode......so the circle continues.
This is what I know about the noise.
Not present @ idle
Starts @ very low acceleration.
Can be controlled with with a light on/off touch on the gas pedal.
I appears to change pitch thru a transmission shift??
I can initiate the noise or quite it with the gas pedal at slow/moderate speeds.
The common denominator appears to be 1500 rpm but it is not present @ 70+ mph @ 1700+ rpm.
So if it's not (presumably) one of the above..... What the hell is it?????
I'll believe almost any thing now, so any assist appreciated.
Ron.
