Checking Crankcase Pressures

Some 2016-2017 Encore and Cruze models equipped with the 1.4L engine (RPO LE2) and 2016-2017 Malibu and Volt models equipped with the 1.5L engine (RPO LFV, L3A) may have an engine oil leak at the crankshaft rear oil seal. Positive or negative crankcase pressures outside the normal operating range, due to a restriction in any of the induction system components, may cause the oil seal leak.


When testing for oil leaks, check for excessively positive or negative crankcase pressures using the Evaporative Emissions System Tester (EEST), J-41413. (Fig. 11) The EEST should be connected at the engine oil dipstick port.


Fig. 11


Connect the tester with the engine off, and then start the engine or record the pressure reading. Normal crankcase pressure readings for the 1.4L engine (LE2) and 1.5L engine (LFV, L3A) are between -1 and -5 inches of water in Park at hot idle. (Fig. 12)


Fig. 12


If the crankcase pressure is in the proper range, follow the diagnostics in the appropriate Service Information.


If the crankcase pressure is excessively positive, above 0 inches of water (0 inches of HG/vacuum), record the cylinder leakage readings and check for improper camshaft cover operation.


If the crankcase pressure is excessively negative, below -16 inches of water (-1 inches of HG/vacuum), inspect for any air induction restrictions in the front air intake duct to air cleaner housing or in the air cleaner housing. Look for any nesting materials, water intrusion, a kinked PCV tube or modifications to the air induction system.


Also inspect the air cleaner outlet duct for a blocked PCV fresh air port. (Fig. 13, #1) A closed port may cause excessive negative crankcase pressure. If the port is blocked, replace the camshaft cover assembly and retest for proper crankcase pressure.


Fig. 13


– Thanks to Raymond Haglund

Security Code Input Message during Programming
Evaporative Pipe or Hose Damage

Leave a Reply

Your email address will not be published. Required fields are marked *