i have a 1990 f-250 4x4 with a 351w . changed oil and filter put in aftermarket gauge . it has 55psi cold but when it gets to operating temp the oil pressure goes to 5 and below. when i give it some gas it does not go up at all in fact when it idles back down it gets lower and the lifters rattle . whats next heavier oil and lucas or rebuild ?

 

how many miles? what oil are you using now?

 

130.000 10w30

 

I think its time for heavier oil.
I got a 302 with 198,XXX that I'm wanting to rebuild. Not because of oil.
Its mostly cause of fuel consumption. I run 20W50 oil, mostly because at 198,XXX it eats oil.

 

I would try 20w50. and go from there

 

302's are known for oil pump failures..... beware of that.

 

I'd be curious to see pressure with 20W50

 

Thicker oil is just gonna be a band aid for a problem you don't need to mask. If the pump is dropping off that much, you need to replace the oil pump. Mine drops off a decent amount (at 188k miles), but it never drops below normal even with stock viscosity oil. When it does, it will get an oil pump.

 

i will give an update when i have done it .

 

Just stock ones or any one you put on a 302?

 

The factory ones.

 

what will i have to do to get the oil pan off ? i dont think i need a rebuild yet it is running 115 to 120 psi compression on all cylinders .

 

Naa man, I'm sure the engine is plenty healthy...just needs an oil pump to keep it healthy. That's why I said "don't mask it with heavier oil". As for pulling the pan, its pretty straightforward I think...never done it on a V8 F-series of that era...so I can't say for certain but I wouldn't figure it'd be too hard.

 

It does drop off quite a bit, I'd still try 20W50 and get some numbers

 

If I'm fine with this many miles you definitely don't need a rebuild. Just take off the bolts and drop it. Shouldn't be any more than that.