more 3/4 ton prob's. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

indy72stepside · 08-24-2002, 02:29 PM

Welll, the cotrol mod stopped it from dying in the street, now I have a new problem. The oil pressure dropped of the other day, so I replaced the sending unit only to realize it was 2 1/2 quarts low after 1000 miles on the change. Now there is now oil spots in the drive and it does not smoke. I think it is leaking from the back of the intake on top of the trans. The big prob now is the oil pressure. Now it runs about 40 psi down the road to an idle at 20psi. Do you think it is the oil pump? Should I just not worry about it? What do you think? If it is the pump, how hard is it to change with the motor in the truck and the 4x4 unit? BTW it is a 95 350 auto

Jeremy

**ThreeQuarter** · 08-24-2002, 03:56 PM

I think it's a common problem that these engines lose the seal in that spot on the intake gasket. A mechanic frined of mine was telling me the gaskets from the factory are simply no good and always give out in a certain corner (forgot which one). Once it's replaced shouldn't keep happening.

I think those oil pressure levels aren't too far out of line. I'll post later what the factory sevice manual says about what the oil pressure should run--I read it the other day and remember the numbers were lower than I thought, but I forgot the exact numbers. 2.5 qts. low sounds like a problem, though. I'd start with the leak at the intake gasket.

indy72stepside · 08-24-2002, 10:51 PM

yeah the leak wil be fixed ASAP. I was wondering about the pump. I am thinking about running a can of engine flush to try to clean up the internals and raise the pressure. Thanks for checking.

Jeremy

Chevyman69 · 08-25-2002, 03:11 AM

I don't put any faith in the factory guages on these trucks, they are all trash. Although what exactly is wrong with 20 psi at idle and 40 onthe road. That is good pressure and there is nothing to worry about pressure wise. Oil leak could be a lot of things, if it is truly losing that much oil you would see something. My rear intake seal blew and the whole undercarriage got oil on it as well as on the ground and I only lost a quart. Your likely culprit is the seal, but you should see something in that short time period with that much oil gone. Who changed the oil last, are you actually 100% positive it was filled all the way in the first place?

indy72stepside · 08-25-2002, 09:17 AM

I am sure it was filled. over the last 200 miles it has lost 1/2 a quart. still nothing on the ground, just on the back of the motor. I don't know, everytime I work on this 95, I look up and see the most reliable thing I own---my 72 stepside---very frustrating

indy72stepside · 08-26-2002, 08:53 PM

well the oil is going out the tailpipe. I am going to run a compression test hopefully it is just the heads.

Jeremy

**ThreeQuarter** · 08-30-2002, 12:28 PM

OK, a little late but here are the minimum oil pressure specs from the 1992 Helms manual (dealer's shop manual):

6 psi @ 1000 RPM
18 psi @ 2000 RPM
24 psi @ 4000 RPM

Sounds pretty low, huh?

And I agree with Chevyman. These factory gauges aren't too dependable.

indy72stepside · 09-01-2002, 09:14 PM

Well, I am above them, but they do seem low. all the cyl. test between 120 and 130. The oil is going past the rings. I have decided to just add oil to it once a week (cheaper than a new engine). It still has plenty of power, so I will ride the wave until I can't ride it any more. Thanks for the help, and if I get the chance, I will hook up a real gauge to it soon.

Jeremy

08-24-2002, 02:29 PM	#1
indy72stepside Registered User Join Date: May 2002 Location: Jeffersonville, IN Posts: 67	more 3/4 ton prob's. Welll, the cotrol mod stopped it from dying in the street, now I have a new problem. The oil pressure dropped of the other day, so I replaced the sending unit only to realize it was 2 1/2 quarts low after 1000 miles on the change. Now there is now oil spots in the drive and it does not smoke. I think it is leaking from the back of the intake on top of the trans. The big prob now is the oil pressure. Now it runs about 40 psi down the road to an idle at 20psi. Do you think it is the oil pump? Should I just not worry about it? What do you think? If it is the pump, how hard is it to change with the motor in the truck and the 4x4 unit? BTW it is a 95 350 auto Jeremy

08-24-2002, 03:56 PM	#2
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,549	I think it's a common problem that these engines lose the seal in that spot on the intake gasket. A mechanic frined of mine was telling me the gaskets from the factory are simply no good and always give out in a certain corner (forgot which one). Once it's replaced shouldn't keep happening. I think those oil pressure levels aren't too far out of line. I'll post later what the factory sevice manual says about what the oil pressure should run--I read it the other day and remember the numbers were lower than I thought, but I forgot the exact numbers. 2.5 qts. low sounds like a problem, though. I'd start with the leak at the intake gasket. __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '94 Ford Explorer XLT 4wd '25 RAM 1500 Laramie 4wd

08-25-2002, 03:11 AM	#4
Chevyman69 Vortec 350's Suck Join Date: Nov 2000 Location: Pickardville Alberta Canada Posts: 544	I don't put any faith in the factory guages on these trucks, they are all trash. Although what exactly is wrong with 20 psi at idle and 40 onthe road. That is good pressure and there is nothing to worry about pressure wise. Oil leak could be a lot of things, if it is truly losing that much oil you would see something. My rear intake seal blew and the whole undercarriage got oil on it as well as on the ground and I only lost a quart. Your likely culprit is the seal, but you should see something in that short time period with that much oil gone. Who changed the oil last, are you actually 100% positive it was filled all the way in the first place? __________________ 69 Chev CST 10 reg cab lwb Daily Driver: 92 Chev Reg Cab LWB Silverado 4x4, K.I.A 7:51 AM 04/22/03 Will be resurrected

08-30-2002, 12:28 PM	#7
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,549	OK, a little late but here are the minimum oil pressure specs from the 1992 Helms manual (dealer's shop manual): 6 psi @ 1000 RPM 18 psi @ 2000 RPM 24 psi @ 4000 RPM Sounds pretty low, huh? And I agree with Chevyman. These factory gauges aren't too dependable. __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '94 Ford Explorer XLT 4wd '25 RAM 1500 Laramie 4wd

08-24-2002, 10:51 PM	#3
indy72stepside Registered User Join Date: May 2002 Location: Jeffersonville, IN Posts: 67	yeah the leak wil be fixed ASAP. I was wondering about the pump. I am thinking about running a can of engine flush to try to clean up the internals and raise the pressure. Thanks for checking. Jeremy

08-25-2002, 09:17 AM	#5
indy72stepside Registered User Join Date: May 2002 Location: Jeffersonville, IN Posts: 67	I am sure it was filled. over the last 200 miles it has lost 1/2 a quart. still nothing on the ground, just on the back of the motor. I don't know, everytime I work on this 95, I look up and see the most reliable thing I own---my 72 stepside---very frustrating

08-26-2002, 08:53 PM	#6
indy72stepside Registered User Join Date: May 2002 Location: Jeffersonville, IN Posts: 67	well the oil is going out the tailpipe. I am going to run a compression test hopefully it is just the heads. Jeremy

09-01-2002, 09:14 PM	#8
indy72stepside Registered User Join Date: May 2002 Location: Jeffersonville, IN Posts: 67	Well, I am above them, but they do seem low. all the cyl. test between 120 and 130. The oil is going past the rings. I have decided to just add oil to it once a week (cheaper than a new engine). It still has plenty of power, so I will ride the wave until I can't ride it any more. Thanks for the help, and if I get the chance, I will hook up a real gauge to it soon. Jeremy



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