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98 Tahoe- Noisy Compressor

kurf on Fri June 13, 2008 6:00 PM User is offline

Year: 98
Make: Chev.
Model: Tahoe
Engine Size: 5.7
Refrigerant Type: 134a
Ambient Temp: 83
Pressure Low: 34
Pressure High: 225

Hi Folks,
I have a 98 Tahoe with a noisy Harrison ht6 compressor. It has an internal clicking type sound, not a real loud sound but its not right. The sound is less when the cooling system first starts up, almost normal but you can hear it. The system has never been serviced. GM gives these pressure as normal low max- 28psi, hi 320. The ambient temp of my test was around 83F and humidify 75%. Running at idle speed the pressures were, lo-38,hi- 210. @ 2000 rpm the pressures were, lo-34, hi 225. When the fan kicked on, the hi pressure dropped to 128psi, the low stayed steady. The vent temp is around 40F. The cooling seems to be the same as it has been since new. I want to repair the system before it dies. I think the compressor is bad but would love to hear what you folks have to say. The GM manual suggest adding 3 oz of oil and .5lb of 134a. I don't see any indication of oil leakage and if I install a new compressor I really don't know how to compensate for the 3 oz added for the trouble shooting. I really don't want to evacuate the charge as GM manual requires, to add 3 oz of oil. I don't have any way to recoupe the 134a. The Tahoe has aux. cooling for the back seats. Thanks in advance for you opinions.


Chick on Fri June 13, 2008 7:12 PM User is offlineView users profile

Is the clicking only with the ac on? or all the time? Check around the halves of the compressor for oily green tell tale signs of a belly bleaker. If you need to change it, go with the Seltec or Sanden clones.. Right now at 80 degrees your high side looks low indicating a leak somewhere..Hope this helps..
Seltec and sanden clones

Email: Chick


Freedoms just another word for nothing left to lose

kurf on Fri June 13, 2008 9:42 PM User is offline

Thanks Chick for the response, The compressor only makes the noise when the clutch is engaged. The sound is internal from the compressor. It not just a klick,klick, its is generated by the rotation, sounds like the lack of lubrication but I don't any indication of such,tommorrow I will look closer at the compressor.


GM Tech on Fri June 13, 2008 10:01 PM User is offline

probably shoe ball lash - internal to the compressor- or if the high side is fluxuating- it coild be reed breakage- which will soon get worse-- as you rotate the compressor by hand- (with engine off) do you feel little "catches" or tight spots?? if so you have the reed failures- and will soon need a new compressor-- if not, then you probably have normal wear and shoe slap.....

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

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