alright my truck is an 89 f250 351. when i first fire my truck up it has about 45-50psi. then as it warms up it gradually drops and finally stays at about 10psi +/- a couple. oil pressure stays the same no matter the rpms. think my oil pump is going bad or you think its time for a rebuild?

 

until the engine starts making noise, I wouldn't bother re-building it...you haven't mentioned mileage

 

well mileage on the truck is 190k... motor is probably 170k. guy i bought the truck off was a chevy queer and an idiot. he said the motor had 70k on it but he also said the truck only had 90k on it, even though the title clearly stated that it had over 100k on it.

 

what type of filter and oil are you using?

 

fl1a and valvoline convential 10w 30

 

thats what i use but 10-40. when i use wix or fram filters my oil pressure goes down. if it goes down that far i would rebuild

 

Does anyone here think 20-50 would make much difference? I know I've used it in the past and it seemed to help with oil pressure in higher-mileage motors. I'm strongly leaning toward it for my 302 at the next oil change ... just figured I'd ask. I'm using 5-30 for the winter, but once warmer weather is here to stay, it's outta there.

 

I used it in my old mustang once when my oil pressure was something to be desired. almost pegged my oil pressure gauge. but i did take off a **** fram filter and i'm pretty sure it had some real cheap oil in it too because when i changed my oil the next time and put a good motorcraft filter on it with some valvoline 10-30 i always had good oil pressure. i've always used 10w 30 after that in all my five liters and never had a problem like this before.

 

I run 20w-50 in my trucks. They take a beating and I don't really care much aobut my truck engines as they've alwsays been small blocks. I figure the 351W in my F-250 blows I got a good 302 to throw in, and if that blows I'm out of small blocks so I'll have to convert to a 460.

Small block Fords are tough though. Last weekend I checked the oil on my F-250 and it was bone dry on the dipstick. It took about 6 quarts to get it to the proper level. It had to ahve been like that for at least 2 weeks as 2 weeks prior I had re-set my idle speed as it got a little higher for some unknown reason (oil pump wasn't pumping much oil presumably). After adding oil the idle speed dropped and I reset it to where I like it.

On my 302 I had in two previous trucks I ran it with a crankcase full of water for a couple minutes to get out of a nasty mud hole. It wasn't just idling either, that was beating the snot out of it while full of water. Drained several gallons of water and a gallon of oil. Fresh oil and I was good for the drive home.

On that same engine I sprung a coolant leak at the water pump and couldnt; fix it on the trail so screw it, drove home with no coolant (about 30 minutes drive, 50 MPH or so). After a while it started knocking and pinging in 5th and I was WOT to maintain speed. Downshifted to 4th to ease load on engine and maybe stop the knocking. Nope, just as bad. For the heck of it I pushed in clutch adn revved it... Knocked and rattled in neutral! Oh well, only 5 mins from home so kept pedal to the metal and finally had to stop because someone stopped in front of me for a left turn. Engine seized as soon as I pushed the clutch. I had several gallons of water with me but it was all frozen, so I found some water and after pouring aobut 10 gallons through it the engine was cooled down. Jumped it and it fired up, drove home normally. Turns out it boiled off all the oil, maybe 1/2 quart came out the pan when I changed it the next day. Fresh oil and filter, new water pump, and put many more miles on it.

Moral of the story, throw some 20w-50 in there and don't sweat it. It's just a small block so isn't worth a darn. If the 20W-50 doesn't do the trick try gear oil. If it goes bang, get a 460.

Either that or if you care about the truck like that then just pull the engine and do a cheapie rebuild. Home, rings, bearings, seals, throw it back in. Cost... $300 + beer.

 

and i thought i was hard on my motors...