oil pressure problem

[muddybuddy]

hey guys, the oil pressure is usually suposed to be around 30 or so on the gauge right? while driving its at about 15 or 20, and then when i come to a top in gear, it appears to go to 0! if i put it in neutral some times it will climb up to 10 or so when stopped. reving seems to help, but only gets it to 15 or so. also it seems like every time i start up, the pressure is different. some times ill have this problem, and then some times i wont, well it wont be as bad.

whats the problem? what do i need to do?

thanks

 

[pauly383]

You can get a mechanical gauge to double check it . Not a bad idea actually .

Could be just a sender or gauge issue . I have actually had the resistor go bad ( ceramic behind gauge ) and it read low .

 

[diesel4me]

what he said!

Yes,I 'd put a mechanical gauge in to make sure the sending unit isn't giving you a false reading..many OEM gauges are not very accurate...

If you DO find the pressure is still very low after you try a mechanical gauge,you might have a worn oil pump,clogged screen on the oil pump pickup,or loose main and rod bearing clearances..thin,diluted oil can reduce the pressure quite a bit too..thicker oil,like 20W50,or SAE40 will help bring up the pressure if its due to worn bearings..also some oil "thickener" like Motor Medic or STP,or "Lucas" Motor treatment will help a lot too...but dont use thick oil in cold weather,it wont flow after it starts quickly enough,or might not let it start period!...

 

[89GMCSuburban]

If you really need to go thick, Valvoline sells an SAE50 oil...

 

[dallassnowman]

I just had the same issue.. just installed new gauges (mech) and noticed it drop to 20 @ idle but will rise to 40-60 when driving..

 

[diesel4me]

thicker still!

We sold Amalie Grade 70W motor oil where I worked,they mostly use it in Harleys..I ran one 283 I had I swore had NO rings in it on the Grade 70W ,two cans of Motor Medic,and it didn't even smoke!..had to add another battery to start it after october came though!.. ...one cold december day,I heard a "POP" after I started it up--it blew the oil filter up,split it down the side..looked like a vagina! ..

I put an old "canister" style filter on it after that--never had another problem!--I noticed the mechanical pressure gauge would peg at 90 psi in the morning,then fall to 25psi as it warmed up!....never blew up that motor,despite trying very hard too..

 

[Russ]

I had the exact same problem recently with my dually. I dropped the pan and put a new $35 oil pump from NAPA on it and now it is running with a constant 50 psi of pressure.

Russ

 

[dallassnowman]

Really...well thats my next route. I've had the truck about 3 years now, its time to drop the pan!! thanks for the info!!!

 

[dirtwarrior17]

Sending unit, oil pump, or old motor...


HIJACK*

Does anybody know if you can overload the psi on the stock oil pressure gauge. My sh!t runs at 80 psi....

END HIJACK*

 

[dyeager535]

6.2 diesel trucks use an 80PSI gauge and sender.

 

[diesel4me]

35 bucks???

I paid 12.99 for a stock Melling oil pump at Auto Zone!-- --the total bill for a new oil pump,(12.99)oil pump screen,(5 bucks!)steel oil pump driveshaft,(8.99)and timing chain and gears (stock Cloyes OEM ones)(20 bucks!) and an oil pan gasket(one peice rubber style,18.99) came to about 65 bucks!(on my 86 305 I put in my C10 from a van)...

I thought that was very reasonable!--even bought a brand newstock replacement oilpan for 35 bucks!--mine was rotted real bad,and weeping..It pegs the needle at 60psi at any speed past idle now--it had good pressure to start with though,I replaced the oil pump because nylon cam gear teeth got into the pump--somehow they sneaked past the screen,and I didn't want the oil pump to croak and seize a good motor up..

 

[dirtwarrior17]

its a 355 with a high volume oil pump... the sending unit is off my 88 350.