Oil pressure gauge - The 1947 - Present Chevrolet & GMC Truck Message Board Network

smokekiki · 10-15-2003, 03:31 PM

My oil pressure gauge pegs,and stays there as soon as the truck starts.What could be the problem?Sending unit?

A.P. · 10-15-2003, 03:44 PM

When did this issue started happen?

smokekiki · 10-15-2003, 06:17 PM

Just bought the truck.The prev owner said it has always been that way.He had it ten years.

SWEET7T · 10-15-2003, 06:24 PM

I have a factory mechanical oil pres. gauge. Mine does the same thing, but I don't worry about it.
When your engine is cold, oil thickens, and as your engine warms up it gets a little thinner. My gauge will peg for about 15-30min till the engine warms up, then my gauge will read about 2/3 pressure (I think my factory gauge is a 40psi, they say on the front of them when you take your cluster apart: either a 40 or a 60psi)
Don't worry about it unless you don't have oil pressure! You can't have too much...

If your gauge is electrical, then I would check the sending unit, or the gauge, it should read 0 when you turn the key on.

71GMC_3/4T · 10-15-2003, 06:29 PM

Sounds just like mine. Only mine sticks sometimes - can do it anywhere. Also, when mine is warm it runs dangerously close to 0 at idle. And that's with 20W50!

A.P. · 10-15-2003, 06:39 PM

When I first turn my truck on, the oil pressure goes above the middle mark but it never pegs at the high mark. I'm also running 10-40 oil.

Gordo · 10-15-2003, 09:03 PM

Hey smokekiki, what's up? My answer to your question is that you have a sending unit installed meant for an idiot light. Replace it with a gauge type sending unit.

smokekiki · 10-15-2003, 09:10 PM

Hey Gordo,how You doing?I just bought this suburban.Haven't got to play with it yet.It is a '71 with a factory BB.It was mounted on a '69 4X4 frame.Was 1/2ton,now 3/4ton.I,ll try to post some pics tommorrow.

Longhorn Man · 10-15-2003, 11:59 PM

There is no sending unit on this if we are talking aboutt eh stock set up, all there is is a tube from the engine to the guage.
Pegging out just means you have some damn good oil pressure, and possably, the wrong oil.
You don't run 80/90 gear oil like Jason does do you?

smokekiki · 10-16-2003, 07:54 AM

Thanks Longhorn Man,sometimes it takes a smack on the head to jump start my brain.The line is connected to the block right above the oil filter.Is this the proper place for a big block?It has 20-50 oil.

tom hand · 10-16-2003, 08:34 AM

Bone stock motors put out 40-50 psi max and that's what the guage is designed for. More than likely the motor has been rebuilt with a higher pressure oil pump so it pegs the guage. I don't think it hurts the guage...I ran a motor in mine that keep the guage pegged all the time for two years, then switched to a GM crate motor and the guage works fine.

Gordo · 10-16-2003, 08:02 PM

My mistake, I was thinking electric gauges. My truck progress is slow. Seems like everything else comes first. I hope to rehang the cab on the rotiserie and finish up welding the head liner back in this Fall but, (there is always a but) I have a few other projects to finish first. Lets see those pics!

**StingRay** · 10-16-2003, 08:07 PM

The stock gauge is a 60 psi unit and with my high volume pump it was always pegged when cold. I swapped in an 80 psi unit often found in the big truck gauge clusters but are overlooked as it is usually the tachs and vacs everybody is looking at them for. Works great.

10-15-2003, 03:31 PM	#1
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,473	Oil pressure gauge My oil pressure gauge pegs,and stays there as soon as the truck starts.What could be the problem?Sending unit? __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

10-15-2003, 03:44 PM	#2
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	When did this issue started happen? __________________ 72 Chevy, SWB, 350engine, TH400

10-15-2003, 06:17 PM	#3
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,473	Just bought the truck.The prev owner said it has always been that way.He had it ten years. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

10-15-2003, 06:24 PM	#4
SWEET7T Try spinnin 4 rear tars Join Date: Sep 2003 Location: Salt Lake City, Utah Posts: 757	I have a factory mechanical oil pres. gauge. Mine does the same thing, but I don't worry about it. When your engine is cold, oil thickens, and as your engine warms up it gets a little thinner. My gauge will peg for about 15-30min till the engine warms up, then my gauge will read about 2/3 pressure (I think my factory gauge is a 40psi, they say on the front of them when you take your cluster apart: either a 40 or a 60psi) Don't worry about it unless you don't have oil pressure! You can't have too much... If your gauge is electrical, then I would check the sending unit, or the gauge, it should read 0 when you turn the key on. __________________ SWEET7T 1970 C10, 2wd, LB, 307/TH350/3.08. PS, PB Last edited by SWEET7T; 10-15-2003 at 06:27 PM.

10-15-2003, 06:29 PM	#5
71GMC_3/4T Weapons Of Construction Join Date: Apr 2000 Location: Colorado, USA Posts: 1,095	Sounds just like mine. Only mine sticks sometimes - can do it anywhere. Also, when mine is warm it runs dangerously close to 0 at idle. And that's with 20W50! __________________ 1971 GMC 2500, 402/TH400 4.10 Daily Driver Lafayette, CO

10-15-2003, 06:39 PM	#6
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	When I first turn my truck on, the oil pressure goes above the middle mark but it never pegs at the high mark. I'm also running 10-40 oil. __________________ 72 Chevy, SWB, 350engine, TH400

10-15-2003, 09:03 PM	#7
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	Hey smokekiki, what's up? My answer to your question is that you have a sending unit installed meant for an idiot light. Replace it with a gauge type sending unit. __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

10-15-2003, 09:10 PM	#8
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,473	Hey Gordo,how You doing?I just bought this suburban.Haven't got to play with it yet.It is a '71 with a factory BB.It was mounted on a '69 4X4 frame.Was 1/2ton,now 3/4ton.I,ll try to post some pics tommorrow. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

10-15-2003, 11:59 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	There is no sending unit on this if we are talking aboutt eh stock set up, all there is is a tube from the engine to the guage. Pegging out just means you have some damn good oil pressure, and possably, the wrong oil. You don't run 80/90 gear oil like Jason does do you?

10-16-2003, 07:54 AM	#10
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,473	Thanks Longhorn Man,sometimes it takes a smack on the head to jump start my brain.The line is connected to the block right above the oil filter.Is this the proper place for a big block?It has 20-50 oil. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

10-16-2003, 08:34 AM	#11
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Bone stock motors put out 40-50 psi max and that's what the guage is designed for. More than likely the motor has been rebuilt with a higher pressure oil pump so it pegs the guage. I don't think it hurts the guage...I ran a motor in mine that keep the guage pegged all the time for two years, then switched to a GM crate motor and the guage works fine. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

10-16-2003, 08:02 PM	#12
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	My mistake, I was thinking electric gauges. My truck progress is slow. Seems like everything else comes first. I hope to rehang the cab on the rotiserie and finish up welding the head liner back in this Fall but, (there is always a but) I have a few other projects to finish first. Lets see those pics! __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

10-16-2003, 08:07 PM	#13
StingRay Senior Member Join Date: Mar 2000 Location: Saskatoon,SK,Canada Posts: 2,482	The stock gauge is a 60 psi unit and with my high volume pump it was always pegged when cold. I swapped in an 80 psi unit often found in the big truck gauge clusters but are overlooked as it is usually the tachs and vacs everybody is looking at them for. Works great. __________________ Saskatoon, Saskatchewan Canada



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