About a week ago, I replaced my head gasket and now im having a problem with my oil pressure.

It has alway ran good and has had great oil pressure, even with a bad head gasket. About a few days ago I noticed my oil pressure guage was bouncing up and down and up and down until it stayed down while I was driving. At startup, oil pressure Is fine, but when the truck get to temp, the oil guage bounces then stays low. I can hear the lifters starting to tick once the gauge goes to low.

I changed the oil yesterday, thinking maybe I was low, which I think i may have been a little low but still the same issue. I did use 5W-20, im not sure if maybe the oil is to thin

I ordered an oil pump this morning so I will get that tomorrow, just incase I do have to change it. Also I will be doing a test with an oil pressure test guage.

Im not to sure what to think, any advice will help.

Truck is 1998 F150 4.6 with 194000 miles. Maybe between 20,000 to 30,000 Miles on the rebuilt engine

 

a good gauge is a good test.
the factory gauge is an on off switch that jumps to mid range at 8 psi.. drop to 7 psi and it goes to zero... increase to 20 psi and it stays at mid range, same as 8 psi.


old engines (pumps) can have significant wear. You said 30K no rebuild, but was the PUMP new ?


check pressure, then install new pump if needed. 5 w 20 is correct oil. With old pump, you may do better with 5 w 30. I would assume this is not a sensor problem since you can hear lifter noise.

 

Ya im really not leaning towards the sensor. I honestly can not remember if the engine builders put a new pump on, If I were to bet, they didnt. And im kicking myself for not replacing it when I had the engine torn apart.

Now that im thinking about it, Would there really be any need to test pressure? Since it is obviously dropping.

Or do certain PSI readings at different engine speeds have different meanings?

 

No, it's not obviously dropping based on the "gauge's" behavior. The gauge is simply a mechanical idiot light, it does NOT measure pressure. You might be seeing something as simple as a drop in battery voltage to the instrument cluster. However, an increase in engine noise isn't particularly comforting.

if you want to actually measure the oil pressure, you will need to connect in (or tee in) an actual gauge.

 

 

 

clogged......with what?

 

+1. Clogged with what?