AC flush TXV question - PeachParts Mercedes-Benz Forum

Phillytwotank · #1 06-08-2022, 07:44 AM

Y’all,
I’m flushing the evaporator. Must the txv be removed.
I have no reason to believe that the TXV is not operating correctly. I did order another one because of an expensive price. But I am concerned about installation challenges, new part quality. Easiest thing for me to do would be to just flush through the hoses, the valve and through the evaporator.
???~Phil

engatwork · #2 06-08-2022, 07:48 AM

The valve will need to be removed to flush the evaporator.

Benzman53 · #3 06-08-2022, 09:54 AM

Whether proper or not, I flushed through mine for the same reasons you state. Works like a champ.

Phillytwotank · #4 06-08-2022, 12:48 PM

ok, so one for remove and one for don't
for some clarification... i am only wanting to flush out any old oil so i can try to make sure it gets refilled with the correct amount after a condenser and dryer swap. not dealing with a compressor failure so I'm not too concerned about debris.

Benzman53 · #5 06-09-2022, 02:56 PM

I was only flushing old oil; no compressor failure. A compressor failure will require TXV removal.

Phillytwotank · #6 06-19-2022, 06:55 AM

I went ahead with thwbflush with the tc valve in place. Seems to flow pretty well in both directions. Up the suction line and out the liquid line then up the liquid line and out the suction line. I have the new part but I figured I take a chance on this first. Put in a new dryer, got it all vacuumed down. Will charge with new refrigerant later today.

BillGrissom · #7 06-20-2022, 01:25 PM

Quote:

Originally Posted by Phillytwotank

... Seems to flow pretty well in both directions. Up the suction line and out the liquid line then up the liquid line and out the suction line. ...

"Should work". I haven't spotted a last-chance filter just before the compressor suction inlet. Older cars often had a damper can on the suction line, though don't know if they had a filter inside. I suspect they were more because the 2-piston compressors of the day gave more pulsing. The Harrison R-4 has 5 pistons, and newer Sanden have up to 7 double-acting pistons (like 14), so very smooth. The aftermarket York on my 1965 Chrysler has 2 pistons, but no surge tank on the inlet and I don't notice any strange noises or issues. My 300D has a large suction hose (-12, 5/8"ID) compared to most cars (-10, 1/2"ID), so gas velocities are slower and perhaps debris isn't easily swept to the compressor, plus an uphill climb from the evaporator. Chevy installed the R-4 up high in 1980's cars, which gave less chance for debris to reach there but also starved them of oil, to caused apparently more failures than in our cars.