Oil preassure dropped to zero. Please help.

[Moe]

Yesterday went on a small trip. I had drove about 200 miles and my oil preassure was holding about 20 psi. For the past two years in between oil changes it drops from 40 to about 20 and thats where it stays while i'm driving. Well yesterday i noticed during the 200 mile drive it was fluctuating between 20-25. About 10 miles before reaching my destination it dropped to about 15 psi. Next thing i know it's about 10 so i stop and pull over. I let it idle for just a minute and it dropped to 0 and the low oil preassure light pops on so i turn it off real quik. I wait for a while start it back up and it still fluctuating bad but don't drop below 20. I have put about another 150 miles on since and hasn't dropped below 20 but i know i have a problem. What could it be? When i started loosing preassure couple years ago i got a little worried but it has never acted like this.

[Botlfed]

check the oil sending unit, behind the intake its 40 bucks at the part store, ive noticed that around a 100,000 miles they go out, if that doesnt fix it which im sure it will, try the oil pump

[youngun]

it could just be the the oil pressure sending unit crapping out or the oil filter stopped up with gunk or collapsed. my mom's truck did similar to this and the fitler was stopped up with gunk from earlier that day when had her oil changed. luckily me and my dad were using the truck that afternoon when it did that and stopped so it didn't kill the engine.

[Moe]

Thanx guys. Ill try the oil sending unit. I have noticed my oil to be a little sludgy lately so the filter could be stopped up. I guess thats another can of worms all together but could be the main cause of the problem. I have been lossing coolant for a while but can never find it in my oil.

[Botlfed]

Thanx guys. Ill try the oil sending unit. I have noticed my oil to be a little sludgy lately so the filter could be stopped up. I guess thats another can of worms all together but could be the main cause of the problem. I have been lossing coolant for a while but can never find it in my oil.

you hafta have a specialty socket to remove the sending unit, if i rember right its like 20 damn dollars

[youngun]

you hafta have a specialty socket to remove the sending unit, if i rember right its like 20 damn dollars

or the grip of a gorilla!

[Botlfed]

[Moe]

Well i took it to a mechanic i know pretty good and he seems to think it the main bearings have alot of wear to them. He said that it is probably caused from the coolant getting into them. He said he could pull the oil pan and check em if they are bad replace and check the crank also. He said i should go ahead and do the oil pump while we are at it. Then he would find the coolant leak and fix that problem also. Most likely a head gasket. I'm gonna get a second opinion tomorrow. I forgot to say that when the presure bottomed out the lifters started pecking. If it was the oil sending unit would they do that?

[Duct_tape123]

Do the cheap stuff first. Change the oil and see if it still has low pressure. How many miles are on the truck? I don't know how a mechanic can tell how much wear is on the main bearings without pulling the oil pan to measure clearances. Don't remember where I heard it, but they say you're supposed to replace the oil pump at 50,000?

[Botlfed]

lifters are prolly gonna start pecking cus you have no oil if its the pump....i dont trust "mechanics" sounds a little shady to me talking about the main bearings and all, but if ya got the money to blow.