oil separator box that was vented directly to the block itself; the breather hose and PCV valve hoses attached to the box, and connected to the induction system. Later engines featured a PCV system that was molded to the cylinder head valve cover. The second feature was internal in nature - the crankshaft main bearings were keyed into the bedplate on the right rear of each transverse web. Later model years featured keys machined on the right front of each web. The third feature would be a slightly bigger camshaft profile that was changed on 1996 and up SOHC vehicles due to a rough idle when the air conditioning was on. 2002 and earlier engines featured a one-piece cast nodular iron crankshaft with counterweights present on either side of each crank pin. A crankshaft tone wheel was present between number 1 and number 2 connecting rod pins, and was machined such that a Hall-effect magnetic pickup mounted to the engine block could read the crankshaft's position as it rotates. 2003 and later engines switched to a two-piece crankshaft. The tone wheel was re-engineered to attach to the crankshaft using three bolts, had a tone pattern substantially different from previous engines, and was moved to the rear of the crankshaft. For this reason, these engines are generally not interchangeable between the 2002 (and prior) and 2003 (and newer) model years. Up to late 1999, this engine type suffered from oil leaks and head gasket failures between the block and cylinder head. Chrysler Corporation used several different designs of composite material head gaskets in an attempt to solve this problem. The cause of the problem was found to be one head bolt hole that was drilled too shallow at the factory, meaning the head bolt bottomed out and could never seal properly. In 1998, a thicker, multi-layer steel head gasket was introduced that eliminated this problem. General Specifications Cylinder Configuration: In-line 4 Number of Valves: 16 (4 per cylinder) Fuel Delivery: Sequential multi-port fuel injection Bore x Stroke: Displacement: Redline: 6500 rpm Rev Limiter: 6750 rpm A588 The A588 is the SOHC version found in most post-2001 Chrysler products. The ECB SOHC version, found in earlier models, is identical except for the crank trigger wheel. When equipped with the newer crank wheel for the new NGC engine computer, the A588 version cannot be directly transplanted into a vehicle originally equipped with the