Medium Duty GX Pump
GX Pump CS4
5,800 PSI max · Water + fan cooled
Water-cooled, 4-stage, 350W, 5800 PSI. Auto-stop, hour meter, rated for 5 hours continuous. 12V with a 110V converter included.
#2 Roger's
Pick
Pick
GX Pump CS4-I
The CS4 with the 110V converter built in. Water-cooled, 4-stage, 350W, 5800 PSI, auto-stop, 5 hours continuous. Roger's champion pick.
Overview
Everything the CS4 does, with the 110V-to-12V converter built in. Plug it into the wall or clip it to a car battery, with no separate power brick. It's a real 4-stage compressor with a built-in water-cooling loop and a 350W motor, and it reaches 5800 PSI (40 MPa). GX rates it at 70 dB and up to 5 hours of continuous running. It has a dual-needle gauge, two-level auto-stop, an hour meter, and a built-in oil/water separator. Before the first run, fill the coolant tank with neutral (pH 7) distilled water or antifreeze. Use antifreeze if it freezes where you live. Turn the grease knob one turn every 6 hours of running, but not before the first 6. GX says the CS4-I is meant for small high-pressure tanks up to 6.8L, not large cylinders. For those, they point to the 5K series. It weighs 29 lb and uses an M10x1 / 8mm quick connector. In the box: the compressor, fill hose, 12V DC cable, AC cable, and manual.
"My #2 pick. It's a water-cooled machine from a reputable company that has been building compressors for other brands for a long time. Parts are available if you ever need them, there's an active Facebook owners group for support, and I like that the inverter/converter is built in, so there's nothing extra to carry."
Water-cooled: don't let it freeze.
Stored in an unheated garage, shop, or truck, plain water in the cooling loop can freeze and crack the water jacket, pump, or lines. Use an antifreeze mix rated for your coldest temperatures, or drain it before storage. Additives like WaterWetter and Purple Ice do not prevent freezing.
Coolant GuideRecommended Add-On
GX Pump Professional-Grade Filter
Heavy aluminum 5800 PSI oil/water filter with a pressure-maintaining valve. Mounts upright on the side of a GX CS4 or CS4-I.
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