Delphi HT-6 Compressor Wear Comparisons

To understand the premature failure of the untreated compressor, internal components of both compressors were closely examined. Several internal components show dramatic differences in wear on load surfaces.

Thrust Washer and Bearing

    Copper Plating                  NOTE: Width of Wear Pattern

The untreated thrust washer shows a wider contact of the thrust bearing rollers. The arrow points to the copper plating that developed on the surface due to heat. The untreated thrust washers showed evidence of spinning on the cylinder block and on the wobble plate. The treated thrust washers showed no such wear.

Shoe / Disc

         Untreated                     Treated                   S.E.M Untreated          S.E.M Treated

The untreated disc shows heat stress (darkened center and outer edges) as well as surface wear. The S E M pictures (photo on right) shows how the machined grooves have almost disappeared. These grooves exist to allow the lubricant to flow between the discs and 
wobble plate surfaces. With the grooves gone, lubricant cannot easily reach this critical 
high load area and therefore becomes a major cause of increased friction.

The treated compressor disc has groove quality and quantity like that of a new compressor.

NOTE: The copper material from the worn / overheated disc is consistent with the material plating the thrust washer of the untreated compressor (above left).

TEFLON Piston Rings

                                  TEFLON Piston Ring

                    Untreated                                     Treated

Loose metal particulates in the lubricant can accelerate deterioration inside the compressor. Piston ring comparison offers a visual confirmation of this process. The untreated Teflon ring is much darker due to the absorbsion of the metal particulates found in the lubricant. This condition causes the Teflon piston ring to become an abrasive surface resulting in accelerated cylinder wear.

Rear Crank Shaft Wear

                  Untreated               Load Surface         Treated

The rear crankshaft segment of the untreated compressor also shows evidence of lateral wear on the bushing in the rear of the compressor. 

These comparisons demonstrate the substantial differences in wear patterns from front to rear of the compromised non-treated compressor to the still fully functioning treated compressor.

Other GM HT-6 Tests
* GM HT-6 (Delphi) Compressor Life Cycle Test 
    (3 Yr / 36,000 Mile)
 * Delphi HT-6 Compressor Clutch Analysis
 * Delphi HT-6 Compressor Wear Comparisons