Jeep 3.8 Engine Priming

 3.8/4.1  -  2007-2011

1.  The intake manifold must be thoroughly cleaned and free of any debris before being installed on this engine. 

Debris such as  parts of pistons, piston rings, and valves from a failed engine can be  trapped in the plenum and runners of an intake manifold.  This debris  can and will be pulled into the replacement engine and cause a second  failure if not removed before the intake is reassembled on the  replacement engine.
 

2.   The oil pump on this engine must be primed and the entire oiling  system must be purged of all air before the engine is started. 

Preferred Method is to use a pressurized system to push clean oil through the entire  oiling system.  You can access it through the access port next to the  oil filter where the oil sender is located.  Follow the priming system  manufacturer’s directions.

Secondary Method for priming this engine is to add an additional  4qts to the system total being approx. 10qts of oil.  Fire engine and  vary RPM between 900-1500 paying close attention to the oil pressure  light or gauge.  If oil pressure is not achieved in the first 15-30  seconds turn engine off, loosen the oil filter approx. one turn.  Fire  the engine for another10-15 seconds.  Oil should come streaming out of  the oil filter indicating air is purged from system.  Shut engine off  and tighten oil filter.  Re-fire engine vary RPM between 900-1500.  You  should have optimal oil pressure.  Run engine for several minutes to  ensure engine is completely primed.  Shut engine off.  Drain the  additional 4qts of oil so that engine is back to proper level on  dipstick.  Once this is complete system is primed, please refer to the Engine/Cam Break In Procedure Page.