I'm changing the oil pump in my '90 F150 with 302. I've heard of people using Vaseline to prime the oil pump after installing a new pump, but is it really ok to do this? I would think you would want to use oil, as it seems that vaseline would be too pasty and not provide a good suction to suck up oil from the sump.

If it is ok, then do I have to take apart the pump to do it? Or can I use a grease gun to squirt chassis grease into the pump instead?


Thanks,


Matt

 

I wouldn't use grease/vaseline. I've never had a problem putting some oil in it before installation. Then I spin oil pump thru distributor hole to prime engine before installing the distributor. If you don't have the distributor out, or don't want to pull it, just pour some oil in pump while turning it, you can see the oil come thru, then install.

 

Chassis grease will not break down enough in the oiling system and should not be used. Vasaline is thinner and can be used to lubricate the pump innards if you have disassembled and cleaned it. If you are just putting a new pump on, put it on and run the oil pump drive shaft prior to reinstalling the distributor.

--Mike

 

I prime a new oil pump by pulling the distributor, use an old distributor shaft and an electric drill, and spin the drill in reverse. This is with the tool I made, inserted where I pulled the distributor out of. You can buy one of these in any auto parts store, if you don't have an old distributor to take apart. As far as the question? No! Do not use grease, vasaline, or anything thick in the oil pump. That's a good way to twist your oil pump drive shaft like a pretzel.

 

Thanks to you guys for the replies. Judging by a couple of your replies, it sounds like I can put on the pump dry and just spin it up with a drill and it will prime itself. Is that right?


Thanks,


Matt

 

It won't hurt to oil the pump before you install it, but yes, you have the right idea.

 

Some repair manuals call for packing the oil pump with Vaseline before use. Most of the ones I have seen that use Vaseline are crankshaft driven pumps that are above the oil level. Oil pumps are positive displacement pumps so Vaseline will not affect "suction". It is actually the atmospheric air pressure that "pushes" oil into the pump. The small amount of Vaseline used will not cause a pump shaft to break.

 

Thanks again, everyone. I went ahead and ran a little oil through the pump last night before installing it, and then I installed it.


Matt