Another Oil Pressure Thread - Page 2

stumpuller454 · 07-07-2009, 04:18 PM

Quote:

Originally Posted by k20_chevy

I know a some chevy's run low oil pressure but mine has hit zero on a few occasions.

bradrhale - what reason did u use diesel as motor flush? was it for the same purpose im trying to accomplish?

stumpuller454 - what the inevitable? A rebuild?

yeah thats all i mean, it may just have a little extra clearances, but i would probly knock abit.

the the bypass valve is a good thing to check out.

merlin5577 · 07-07-2009, 05:37 PM

Fill the engine with 5W-40 motor oil. If your pressures go up the oil pump is fine, and the bearings are causing low pressure. If the pressure stays the same the pump is bad. Easy enough.

k20_chevy · 07-07-2009, 06:43 PM

Quote:

Originally Posted by merlin5577

Fill the engine with 5W-40 motor oil. If your pressures go up the oil pump is fine, and the bearings are causing low pressure. If the pressure stays the same the pump is bad. Easy enough.

From an earlier post i have great pressure at first start but after it gets to normal operating temps i have very low oil pressure. Isn't 10w-40 thicker than 5w-40?

merlin5577 · 07-07-2009, 07:51 PM

Quote:

Originally Posted by k20_chevy

From an earlier post i have great pressure at first start but after it gets to normal operating temps i have very low oil pressure. Isn't 10w-40 thicker than 5w-40?

No. They are both 40 weights and will behave the same when the engine is up to operating temperature. The first number is how the oil behaves cold. You said you had great pressure with cold oil so the 10W proves nothing. Try a 5W-40 and see if there is any difference.

k20_chevy · 07-07-2009, 08:09 PM

Alright will do. I'll update everyone by end of weekend, on what happens. Thanks everyone for your help up to this point.

k20_chevy · 07-18-2009, 09:39 AM

Hey guys, sorry for the long delay. So I flushed the engine with diesel fuel. Then made sure it was all out and added 5w-30 oil and new filter.

So I get 50psi during warm-up and 10 psi at idle in park and 5psi in gear. I'm thinking to try another pump because I read somewhere a guy tried 4 oil pumps before he got one that gave him the oil pressure he needed. I measured from the outside top of pan to botton is about 7".

Anyone got any more options or ideas that I can try before I buy the pump in the link below.

Melling M99HVS

mudseeker · 07-18-2009, 11:15 AM

it's common for an old gen1 engine to run low oil pressure. throw some lucas in and forget about it or tear it down and replace the bearings and what not after having the block hot tanked.

merlin5577 · 07-18-2009, 02:43 PM

Did you try the 5W-40 oil?

k20_chevy · 07-18-2009, 02:49 PM

Quote:

Originally Posted by merlin5577

Did you try the 5W-40 oil?

No 5w-30. I'm thinking about trying straight HD-40 oil. The pressure is great at startup but falls off when it warms up.

so at first start is the truck running at the 5w or the 30w using 5w-30

leolkfrm · 07-18-2009, 03:54 PM

if you are going heavier try 10w30 or 15-40

07-07-2009, 08:09 PM	#15
k20_chevy Senior Member Join Date: Apr 2009 Location: Lorain Posts: 95	Alright will do. I'll update everyone by end of weekend, on what happens. Thanks everyone for your help up to this point. __________________ 1981 Chevy K20 3/4 ton 4x4. 350 with th400 trans. 33x12.5x16 Super Swamper SSR. open D44 front and 14-bolt rear with detroit locker. 3" body lift.

07-18-2009, 09:39 AM	#16
k20_chevy Senior Member Join Date: Apr 2009 Location: Lorain Posts: 95	Hey guys, sorry for the long delay. So I flushed the engine with diesel fuel. Then made sure it was all out and added 5w-30 oil and new filter. So I get 50psi during warm-up and 10 psi at idle in park and 5psi in gear. I'm thinking to try another pump because I read somewhere a guy tried 4 oil pumps before he got one that gave him the oil pressure he needed. I measured from the outside top of pan to botton is about 7". Anyone got any more options or ideas that I can try before I buy the pump in the link below. Melling M99HVS __________________ 1981 Chevy K20 3/4 ton 4x4. 350 with th400 trans. 33x12.5x16 Super Swamper SSR. open D44 front and 14-bolt rear with detroit locker. 3" body lift.

07-18-2009, 03:54 PM	#20
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,932	if you are going heavier try 10w30 or 15-40 __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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07-07-2009, 05:37 PM	#12
merlin5577 Banned Join Date: Nov 2008 Posts: 675	Fill the engine with 5W-40 motor oil. If your pressures go up the oil pump is fine, and the bearings are causing low pressure. If the pressure stays the same the pump is bad. Easy enough.

07-18-2009, 11:15 AM	#17
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,155	it's common for an old gen1 engine to run low oil pressure. throw some lucas in and forget about it or tear it down and replace the bearings and what not after having the block hot tanked.

07-18-2009, 02:43 PM	#18
merlin5577 Banned Join Date: Nov 2008 Posts: 675	Did you try the 5W-40 oil?