'01 E430 A/C blows warm (readings inside)

[pmizell]

A couple of weeks ago my A/C degraded from freezing cold to sorta cool to current warm air. My compressor engages (clutch and hub) and the pushbutton diagnostics showed I was a little lacking on the low side ... no error codes (except sun sensor) were pulled. Seemed like a classic low refrigerant issue. That is until I tried to pour a can of 134a in the system but there was too much pressure at the low port and it wouldn't take it.

Bought a manifold gauge to see what's really up and today with 85F ambient and engine rev'ed to 1500 rpm my pressures settled in at 95 low, 145 high. That's obviously a high low and a low high. Any experts have a general idea what's going on here? Sounds to me like there's either a restriction in the system or the compressor is almost shot although it has never made any unusual noises to indicate possible failure.

I'm at a loss. Any help would be much appreciated!

[mbdoc]

99% of the time...those readings are due to a bad compressor,
the other 1% are from a bad expansion valve.

[pmizell]

Thanks DOC for the reply. I figured it was the compressor but I'm not too disappointed because I'm one step closer to solving the problem. I've found a new Denso replacement for ~$300 which sounds very reasonable and the drier and expansion valve are cheap.

I see some other "OE" compressors out there that looked tempting until I found out they're from China.

[pmizell]

AC is back on! Installed a new Nipondenso compressor, receiver/drier and expansion valve, changed the V belt, flushed the evaporator, condenser and all the hoses, added PAG 46 DEC oil to meticulous specs, pulled a vacuum for a few hours (very hot and humid in Houston) and 3 cans of 134a later the system is blowing icicles.

With 95F ambient here I'm getting 37F from the evap temp sensor! (seen it dip to 35 a few times while highway driving)

What a relief....