Cooling System Pressure Test Pump 4-30 PSI with Case

Hand-operated cooling system pressure tester, OEMTOOLS part number 27069. You get the steel pump body, a 4 to 30 PSI gauge, the hose, and the standard radiator filler-neck coupler in a blow mold case. It is the pump, not a full adapter set - the vehicle-specific neck and coolant-bottle adapters for imports are sold separately and this pump is built to accept the regular OEMTOOLS cooling system adapters. The case has empty room in it for exactly that reason.

The reason a transmission bench keeps one of these on the shelf: on a large share of GM and Ford applications the ATF cooler is a tube bundle sitting inside the radiator's tank, not a separate cooler out front. When that bundle cracks, coolant and transmission fluid trade places. You pull the pan and the fluid is pink and frothy like a milkshake, or the overflow bottle looks like strawberry milk, and the clutch packs and converter have been running on antifreeze. Pressurizing the cooling system and watching the needle tells you the leak is internal before you rebuild a unit and hang it back on the same bad radiator. It is also how you prove a job after a cooler line or radiator swap, before you fill and road test.

Bench and driveway procedure: engine cold. Take the radiator cap off, clamp the coupler onto the filler neck, and pump to the pressure stamped on the cap - most factory caps are 15 to 18 PSI, and the 30 PSI gauge covers those with room left over. Do not overshoot the cap rating or you will split a heater core that was fine. Let it sit ten to fifteen minutes and watch the needle. A needle that holds means the system is sealed. A needle that walks down with no puddle underneath means the coolant is going somewhere internal: heater core, head gasket, or the transmission cooler in the radiator tank. Pull the trans dipstick and look at the fluid to tell those apart. When you are done, use the lever relief valve to bleed the pressure off before you crack the coupler loose so you are not wearing hot coolant.

Steel construction, limited lifetime warranty from the manufacturer. Gauge face is marked in PSI with the common cap-rating bands printed on it, so you can read a pass or fail without doing math on the fender.