Low Oil Pressure - The 1947 - Present Chevrolet & GMC Truck Message Board Network

four-eyed stang · 04-19-2006, 12:49 AM

I recently bought an 81' with a 305. When I start it up it registers 45 psi of oil pressure. When it warms up it registers 15 psi driving down the road but runs 0 psi at idle. I don't hear any tapping or knocking and have ran it about 50 miles. Could this be a bad sending unit or could my bearings be going out?

79BIG10 · 04-19-2006, 12:57 AM

What oil are you running? If you haven't changed it in a while you might. But my best bet is a bad unit. I would repalce it and if still not fixed change the gauge. Better to do those than tear into it.

four-eyed stang · 04-19-2006, 01:02 AM

I am running Castrol GTX 10-40. Changed it about 3 weeks ago. I wouldn't figure that it was an oil pump. I had heard years ago that bearings could do this but I have not seen it first hand.

79BIG10 · 04-19-2006, 01:04 AM

Oil probably wouldn't be a problem then. When you run a thinner weight oil sometimes it would mess it up but I would change the sender first.

Karl Hoh · 04-19-2006, 03:17 AM

Find someone with a mech. test gauge and check before buying anything. I've tried the " I hope it's the sending unit" route before. Dollars to donuts the bearings are worn out. Just my 2 cents.

04-19-2006, 12:49 AM	#1
four-eyed stang Registered User Join Date: Dec 2005 Location: Dallas Posts: 29	Low Oil Pressure I recently bought an 81' with a 305. When I start it up it registers 45 psi of oil pressure. When it warms up it registers 15 psi driving down the road but runs 0 psi at idle. I don't hear any tapping or knocking and have ran it about 50 miles. Could this be a bad sending unit or could my bearings be going out?

04-19-2006, 12:57 AM	#2
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,774	Re: Low Oil Pressure What oil are you running? If you haven't changed it in a while you might. But my best bet is a bad unit. I would repalce it and if still not fixed change the gauge. Better to do those than tear into it. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

04-19-2006, 01:02 AM	#3
four-eyed stang Registered User Join Date: Dec 2005 Location: Dallas Posts: 29	Re: Low Oil Pressure I am running Castrol GTX 10-40. Changed it about 3 weeks ago. I wouldn't figure that it was an oil pump. I had heard years ago that bearings could do this but I have not seen it first hand.

04-19-2006, 01:04 AM	#4
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,774	Re: Low Oil Pressure Oil probably wouldn't be a problem then. When you run a thinner weight oil sometimes it would mess it up but I would change the sender first. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

04-19-2006, 03:17 AM	#5
Karl Hoh A little east of nowhere Join Date: Feb 2006 Location: LaBroquerie,Manitoba Canada Posts: 168	Re: Low Oil Pressure Find someone with a mech. test gauge and check before buying anything. I've tried the " I hope it's the sending unit" route before. Dollars to donuts the bearings are worn out. Just my 2 cents. __________________ 68 C10 250 4spd 69 C20 327 4spd 69 910 250 3spd 80 K10 350 4spd 76 C60 366 5spd school bus "THERE'S NOTHING YOU CAN BREAK THAT SOMEONE CAN'T BE PAID TO REPAIR"

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