Automotive Air Conditioning Information Forum (Archives)

drhill on Sat July 27, 2013 12:21 AM

Year: 2003
Make: Mercury
Model: Marauder
Engine Size: 4.6
Refrigerant Type: 134a
Ambient Temp: 105
Pressure Low: 25-60
Pressure High: 150-250
Country of Origin: United States

Hi Everyone, just got a new denso compressor - turned it a bit by hand with the supplied pag46 oil that came in it (full 7oz Charge) and it was still really tight. I installed it along with a new condenser, orifice tube, accumulator and flushed the lines and evap. did a deep vacuum and during charging the ac comp cycled on and off as the charge was put into the system. FYI - I left 4 oz in the compressor and spread the other 3 oz around the system.

The High side charge hose and the high side gauge vibrated with the clutch engaged? Also, once a nearly full charge was achieved, the compressor tried to stay on continuously but the clutch kept slipping (high side hose still vibrating). I shut her off to avoid any damage and pulled the compressor - still just as tight as it was out of the box. Any ideas? Is it bad?

Thanks!!

GM Tech on Sat July 27, 2013 8:14 AM

It is tight- probably been on the shelf a few years before you bought it-- the clutch needs burnished- I'd run it in- your pressures are not that bad- so I don't suspect any restrictions- you need to let the clutch cycle- or force it to cycle ( plug/unplug compressor relay) about 50 times and things should get better.

Hi sidew hose vibration is not uncommon- it is showing the compressor pulses - usually hi side gage can vibrate as well- I'd say just run it in and it will be fine..

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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......

drhill on Sun July 28, 2013 2:27 AM

drhill on Sun July 28, 2013 2:41 AM

Awesome...thank you! I was hoping this was the case, but once I smelled burning clutch I figured I better ask the question.

Also - most recommend to spread out the oil based on manufacturer recommended oil matching proceedures...is there any reason why I couldn't just leave the full oil charge in the compressor upon replacement in the future? Of course, assuming accumulator is replaced as well as a system flush performed...

GM Tech on Sun July 28, 2013 7:45 AM

Every engine ever started on an assembly line has the a/c compressor filled with the entire oil charge amount- so I never distribute the oil- It is a wive's tale.

-------------------------
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......

drhill on Sun July 28, 2013 10:33 PM

Ha...i suspected as much. The compressor is the only part in the system that needs lubrication.

iceman2555 on Mon July 29, 2013 9:01 PM

The compressor may be the only part that needs lubricant, however, the lubricant does not remain in the compressor. It is migratory and if the system is not serviced properly, the lubricant flow will be reduced and the compressor will pump itself dry and fail.
A complete and through service should be considered with any compressor installation. Short cuts often lead to premature compressor failure.
Good luck

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson