D'Man

I have a 91 lumina euro 3.1L that appears to have an oil leak on the back side of the engine (next to firewall). A real tight spot. Any ideas where this oil could be coming from. Oil is on the engine block all the way to up to exhaust manifold. Could it be the back valve cover? How in world do you get to this cover. Tilt the engine forward?

Thanks.

NeonKnight

possibly the oil pump drive. i have the same car you do, and mine leaks but its not the puimp drive for me. There is information laying around these forums about the oil pump drive. hope this helps ya out.

MikeZ34

Yes its probably your oil pump drive. The oil pump drive is the remaining shaft that use to be the distributor. They only have a rubber O-ring and can leak very badly. I just fixed mine on my 93 Z34 and it was leaking very bad down the back of the block and front. In order to fix it you need to take off the upper intake manifold. Disconnect the fuel line and injectors and take off the lower intake manifold. You might have to take off the back head but then it gets to be a job. I have a 3.4 liter and for me to replace the O-ring I would had to take off the back head because the corner of the head sits over top of the oil pump drive. I'm not sure on the 3.1 liters if your need to take off the back head. If you would need to off the back head you can fix it without taking it off by just slipping a regular distributor mounting gasket under the oil pump drive hub. Thats what I did and it stopped the leak. You can left up the hub of the oil pump drive about 1/4 -1/2 inch up before it touches the bottom of head. You need to take off the hold down clamp for the oil pump drive before you can left it up. Cut the gasket on one side, put Permatex Super "300" Form-A-Gaskets Sealant on it, spread open the cut mark on the gasket and slip it under around the oil pump drive and join the spot you cut and tighten it up. Now if you can get the oil pump drive shaft out without taking off the head I would put both the o-ring and gasket on.The part # for the gasket is Felpro 70194 and the o-ring is Felpro 70800. Also replace both intake gaskets and torque the intake bolts at 30 foot pounds starting in the middle doing a criscross pattern.