Just changed the oil in my 47 flathead 6 and now I have no oil pressure. I took the sending unit out and put a gague in and it is 0. What gives? PK

 

Hi Kelly, good to see another MT flathead truck around.

Did you have pressure before? Did you change the filter also?

Did you happen to pre-fill the filter canister? (don't)

I'm more familiar with V8's but this stuff should apply to both.

 

Welcome to the Forum:If you have that big inspection cover on the bottom of your pan I would pull it and check the condition of the pickup screen. How long did you run it prior to making the determination that the pump was not working. What was the pressure at idle and at moderate speed prior to the oil change. My 51 Flathead 6 will hold 15psi at idle and 45-55 above idle.

 

The oil pressure was low (for me) when we got the truck last week. It had sat for some years. So getting it started was the first job.

I only ran it at an idle after the oil change and noticed the oil gague was lower than before. I shut it down and checked the sending unit to see if power was at the lug and there was. So I pulled the sending unit and installed a gauge, started the engine at idle and saw 0 psi so I shut it down.

I didn't change the filter as I just wanted to get some oil in the engine that I knew what it was. This engine has a big round drain plug, I didn't look up inside the pan so I don't know how the screen looks like. PK