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Allows use of The 'Cooler Bleeder to purge air from the engine's cooling system. If you've already committed to a Cooler Bleeder, significantly less expensive option versus buying a vacuum lift kit to purge air pockets in the engine. Also works with our leak tester to pressure test your engine cooling system for leaks.


Modified Astro Pneumatic radiator adapter to be used in conjunction with The 'Cooler Bleeder and Series 2 fitting.  The Astro Pnuematic Style 41 adapter, which works for many late model GM (Including C7/C8 Corvette) and Ford fitments is our standard offering.  If you need a different adapter, let us know and most can be sourced and converted for comparable pricing.   See Astro Adapters PDF for many of the potential fitments available


Note: This only operates as a manual vacuum bleeder. The automation functions of The Cooler Bleeder are not used during bleeding. No wiring is to be hooked up when used in manual mode.



  • Fill engine's cooling system as full as possible.
  • Fill Cooler Bleeder ~1" above suction hose inlet with engine coolant.
  • Fully open calibration valve and pump shut-off valves on Cooler Bleeder.
  • Turn on vacuum pump.
  • Slowly shut calibration valve until coolant level starts to rise in pot. Adjust calibration valve to apply as much vacuum as possible without ingesting coolant into vacuum pump.  Keep system under vacuum for 1-2 minutes.
  • Turn off vacuum pump and release all vacuum on the system.
  • Refill Cooler Bleeder to 1" above inlet again, if needed.
  • Start engine and allow engine thermostat to open. Carefully monitor engine temperature to ensure engine is not overheating.
  • Turn on vacuum pump and again use calibration valve to place system under vacuum, now with engine running. Again, do not allow coolant levels to rise far enough to ingest into vacuum pump. Continue to monitor engine temperature for overheating
  • Run engine for 1-2 minutes under vacuum conditions.
  • Turn off engine and wait for engine and coolant to completely cool off
  • Remove the Cooler Bleeder from vehicle and reset coolant levels to factory spec.   If bleeding from the radiator, this is as typically as full as possible.  If bleeding from an expansion tank, you may need to remove some fluid from the system to get to the correct cold/hot lines on your tank.

Engine Radiator Bleeding Adapter

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