PRIMING AN LS GM OIL PUMP
Priming your oil pump and your engine before start up of a new engine is very important. No new engine should be started up dry, but it is often difficult on new engines with a front crank driven oil pumps to prime. Here is where we need a pressurized oil priming tank. – Sometimes a shop may replace an oil pump in the car. This is common with the GM Gen 3 and 4 or LS platform engines. There are some important steps that need to be addressed before starting the engine. – On the GM LS engines the oil pick up screen is attached to the bottom of the pump and sealed with an o’ring. It is important that the correct o’ring be installed or air may leak in and cause severe engine damage. Use engine oil to lubricate the o’ring and install it on the pick up tube, then install the tube to the oil pump. We should also point out that now is a good time to install a new pick up screen rather than chance getting any debris from the old screen into you new pump. This can easily cause a by-pass to stick, creating a low or no oil pressure condition. Also, a screen clogged by varnish build up can starve your engine of oil. – When installing the pump, it is important to locate the pump and install the locating bolts just finger tight. Once all the bolts are snug, it is important to torque the bolts to the correct torque spec, working around the pump in a star pattern. Now it is time to complete the engine assembly. – Make sure your oil level is correct and fill the new oil filter with new clean oil before installation.- Now, to prime the pump, use an 8mm allen wrench to remove the oil galley plug on the left lower front corner of the block. Use a 2 ft long length of 3/8 I.D. fuel hose and screw it about and inch and a half into the hole where you just removed the plug. Place a funnel over the hose and slowly pure about 8 oz. of engine oil into the funnel. – Wait about 3 minutes, then remove the hose and replace the oil galley plug. – Your pump should now be primed and ready for the engine to start. If you do not have oil pressure right away, shut down the engine and do not start it again until you have corrected whatever has caused the problem.

Engine Pro Technical Committee
with special thanks to Melling Engine Parts

November, 2016