i have a 1990 f150. it has a 302 v8. there's a oil pressure guage in the dash

usually the needle sits right in the middle of the normal, pointing straight down.

but sometimes i start the truck and the needle starts to move up, but then drops back all the way to the left. i turn it off, start it again and then it's fine again

some people say this is a dummy switch that it doesn't indicate any actual pressure level.. just whether the fuel pump is working or not. but it sure doesn't act like a dummy switch

sometimes i'm driving and the needle goes down a little bit for a while then comes back. it uses a little oil too and adding it back up a quart will bring the guage back into line

anyway this is a 1990 so should i change the oil pump? anyone got any ideas on what makes these things go and what could make it malfunction. is it powered electric or mechanical. is there a wire to check. the only computer codes for the engine say that my air/fuel mixture is lean on fuel. i read there's a filter and it might be good to just take off the pan and clean it all out

but i read it's a chore to get to the oil pump. how do i lift up the engine high enough to drop the oil pan without damaging anything? and if i do all that i'll want to just change the oil pump. is there a trick to that.

i'd like to hear anyone taht can share some advice and experience on this

 

your factory oil pressure guage is electrical.

cheap way to do, is replace the sending unit.

 

I would check it with an actual mechanical guage first. If the pressure is not ok then its either the bearings or the oil pump. I would be willing to be its the actual guage though, mine does the same thing. Do you hear a knock when it reads low?

 

like thomadm said check it with mech gauge first.

my six had a clogged oil pickup screen.

i will give tips on removing oil pan if you go that way.

 

had the same problem sweated bullets, mechanic put in a new sender/sensor on the block(20.00cdn)not a problem now they checked the pressure with a regular type gauge.

 

just so we're on the same page.. the guage and sending unit are electric but the pump is mechanical?

there's no knocking from the engine. it gets a little hotter, or feels hotter to the touch up top than other vehicles i've had. but the thermostat says the temp is fine

i read about the filter screen where the pump picks up the oil. could that be clogged up so that i'm experiencing occasionally lower oil pressure. i'd just imagined this situation would just continue to get worse as it got more clogged but i have no experience with this thing

i wouldn't mind just taking off the oil pan to have a look at the pump. but i wouldn't know where to begin removing things so i can raise the engine without breaking anything and getting it back into place properly

 

oil pump is mechanical.

YOU NEED TO GET A MECHANICAL GAUGE TO PROPERLY CHEK YOUR PRESSURE BEFORE YOU GET YOUR PANTIES IN A BUNCH.

i hate using caps. so you know i mean it.

look down filler with a flashlite and engine running to see if oil is moving through engine.

oil pan is a mother to get out. you may want a shop to do it if you are afraid of breaking things.

 

try this, search for "engine knock and zero oil pressure at start"