Service slants

Motor, Oct 1999 by Juran, Ken

As on any engine, of course, a leaking oil pan gasket could appear to be a leaking front cover. Nissan says that if there's no oil along the Altima's front cover/cylinder block mating surface just below the O-ring area, then the oil pan gasket is a likely suspect. As with the separator, the oil pan gasket may not leak with the engine running, but it may leak after the engine is shut down. Nissan suggests using a leak-tracing dye and UV light to rule this one out.

And don't forget about the front crankshaft seal. If you find that oil has sprayed all over the front of the engine, the front seal is a likely suspect. Check for wetness on the back of the crankshaft pulley; A handful of oil means you could be dealing with high crankcase pressure from a clogged PCV system.

Once you've determined that the front cover 0-ring is definitely your target, disconnect the battery and get the car positioned on a lift. Remove the VSS horn, if the car has one, then pull the alternator and the coolant and power steering fluid reservoirs. Rig up an engine support bracket across the engine bay and hook up to the right rear of the cylinder head. Keep the engine support bracket away from the a/c lowside charging port to avoid damage. Then, pull the upper right engine mount and its bracket.

Next, remove the three timing coverto-cylinder head bolts and the two upper timing cover bolts, including the upper idler pulley bracket. Then raise the car, drain the oil and pull the right front wheel and inner plastic fender shields. Get the a/c compressor out of the way and tie it off to the front of the frame. Pull the a/c idler pulley bracket, the exhaust pipe flange nuts and bracket and the engine crossmember and mounts.

Now pull the lower rear engine mount support bracket bolts and reposition the bracket. Remove the steel oil pan, oil baffle plate and aluminum oil pan. (Note that two bolts for the pan are located behind the flywheel cover plate.) On 1993-94 Altimas, remove the oil pickup tube bracket bolt, but leave the pickup in place. Use a puller to yank the crankshaft pulley (you may need to lower the engine to get enough clearance). Pull the power steering pump bracket from the block (top bolt first) and reposition it for clearance.

Next comes the lower timing cover bolts, the lower power steering idler pulley and one lower PCV bolt.

Get the power steering pump out of the way. Then pull the upper timing cover bolts and two upper oil separator assembly bolts. Finally, yank the timing cover. Nissan says you may need to lower the engine to provide clearance for the chain tensioner housing of the timing cover to clear the frame.

Putting it all back together is at least as hard as taking it apart. Here are some tips: Start by cleaning all the gasket surfaces. The new O-ring is Part No. 15066-5E500. When applying RTV to the timing cover, don't fill the deep channel closest to the O-ring seal. As you carefully maneuver the timing cover back into place, stop! Nissan suggests using a screwdriver or other suitable tool to remove any RTV that may have smeared onto the timing chain and guide area.