I recently took my timing cover off and according to Bentley, I need to prime the oil pump before I put the cover back on. Only thing is, the manual doesn't tell me how to prime it. Any tips?

 

Can anyone share their process for priming the oil pump?

 

I'd also like to be educated on this, as I plan on removing my timing cover (oil pump) to replace the T/C gasket and two internal seals when I do my belt tensioner/crankshaft pulley/idler pulley/crankshaft seal replacement in an end of summer service.

For instance, does one need to prime an existing oil pump which comes off an engine which is running properly like mine, therefore, there is already oil in it?

Or, does one only need to prime a brand new oil pump which is being installed for the first time, and thus "dry" inside?

 

Except putting oil in the upper hole of the pump in the cover, I don't really see how it's possible. The cover and the pump are off, there's no oil or not much remaining in the pump and putting any in there would probably result in a mess since there's no seals to keep the oil in there. It's a crank driven oil pump, unless the cover is on with all the seals and gaskets, you can't really circulate oil in it.

On older cars, you could prime the engine with a drill, but it was still with everything bolted on. I've done timing covers on a bunch of modern Toyota vehicles and never did anything of that nature when putting them back together.

 

I get around this by pulling the fuse to the fuel pump and letting it crank awhile without starting whenever I have the front cover /oil pump off. One of the manuals says to pour oil in the two holes, but when you do the it mostly ends up on the floor.

 

After it's put together, I think priming would just involve cranking the engine for a bit with the coil pack unplugged to prevent ignition - gets the oil circulating.

My Bentley manual says "before timing housing cover installation, prime oil pump by filling with engine oil". Since it won't really fill and will just drip out of the inlet, my guess it it's just to "wet" the moving parts to get a good suction seal when starting the motor.

 

Unplugging the coil is not a good way to crank without starting. You then shoot gas into the cylinder. Best case is it accumulates in the oil. Much better to pull the fuse for the fuel pump. Same is true when doing a compression test - stop the flow of fuel.

 

Agree that it's a good idea to cut the fuel, but I'd still disconnect the coil, otherwise residual fuel already in the system might cause engine to start - even if only for a moment.

 

I've rebuilt more oil pumps than I can remember on race engines and I've never "primed" one other than to make sure the parts were wet with oil when assembled. They always built pressure with a few seconds of cranking. I had one (non-race) Toyota engine that didn't, but the pump might have been a bit worn.

 

I just put a little oil in it when I did my rebuild, figured that was good enough.

Nik

 

+1 should not take much , a little oil and gtg.