What are the possible problems when oil is leaking into my 1995 Chevy lumina engine?

Answer 1

If the engine is the 3.1L V-6, the answer may be a simple one depending on where you notice the oil leaking. 1. If it is coming down the back side of the engine mainly and leaving marks toward the middle of the car, it has a very common problem, GM assembled the cars with an improperly designed seal around the oil pump driver. This driver mounts in the block where the distributor would normally go, however they changed the system to a DIS ignition (distributorless) however the distributor in most if not all GM motors not only controls spark but links the camshaft to the oil pump. So by replacing the distributor the driver had to be created. The fix is somewhat simple if you are slightly inclined and you have a larger toolkit at your house. You need to remove the air duct, throttle body, EGR valve and upper plentum. Once all these parts are removed you should be able to see a different color round part below, near where the transmission mounts to the engine block. There is one hex bolt that holds a small wedge on the round (about 2" diameter) top of the pump driver. You remove the hex bolt, the wedge and pull the driver straight up and out, you might need to pry up with a screwdriver first to get it loose. You will need to replace the O ring that is seated on the unit you removed. Assembly is opposite of removal and it should solve your problem. 2. another more simple problem if it is mostly leaking from the front is the front pressure sending unit, it should be located on the front of the block to the driver's side of the oil filter. If you remove the wire that goes into it, you will notice oil on the inside of the plug if it is bad. You can purchase this at a parts store for a small price and it is very simple to replace with a 1 1/8" socket if i remember correctly. Both of the above are more annoying causes of leaks if you have checked the obvious such as loose oil filter, loose oil plug, or leaking valve cover gaskets.