GMC Certified mechanic

[Black Owl]

Do we, by any chance, have a member who is a certified GMC mechanic????

Trying to find out what the oil pump flow rate is for a 4.3L engine.

Thanks much

[Power Trippin]

This is straight out of gm service information, does not specify flow rate, only psi., hope

this helps.

 

Oil Pressure Diagnosis and Testing

1. With the vehicle on a level surface, allow adequate drain down time, 2–3 minutes, and measure for a low engine oil level. Add the recommended grade engine oil, and fill the crankcase until the oil level measures FULL on the oil level indicator.
   
2. Operate the engine and verify low or no oil pressure on the vehicle oil pressure gauge or the oil indicator light. Listen for a noisy valve train or a knocking noise.
   
3. Inspect for the following:
   
   • Engine oil diluted by moisture or unburned fuel mixtures
     
   • Improper engine oil viscosity for the expected temperature
     
   • Incorrect or faulty oil pressure gauge sensor
     
   • Incorrect or faulty oil pressure gauge
     
   • Plugged oil filter
     
   • Malfunctioning oil filter bypass valve
     

[*]Remove the oil pressure gauge sensor or another engine block oil gallery plug.

[*]Install an oil pressure gauge.

[*]Start the engine and then allow the engine to reach normal operation temperature.

[*]Measure the engine oil pressure at the following RPM:

Specification

1. 42 kPa (6 psig) minimum, at 1,000 RPM
   
2. 125 kPa (18 psig) minimum, at 2,000 RPM
   
3. 166 kPa (24 psig) minimum, at 4,000 RPM
   

[*]If the engine oil pressure is below minimum specifications, inspect the engine for one or more of the following:

• Oil pump worn or dirty
  
• Malfunctioning oil pump pressure relief valve
  
• Oil pump screen loose, plugged, or damaged
  
• Excessive bearing clearance
  
• Cracked, porous or restricted oil galleries
  
• Engine block oil gallery plugs missing or incorrectly installed
  
• Broken valve lifters
  

 

© 2013 General Motors. All rights reserved.

[Black Owl]

Thanks Kevin,

Unfortunately, we are way beyond this point. We are now trying to figure out why there was insufficient lubrication which took out all the connecting rod and main bearings.

[Condor]

Thanks Kevin,

 

Unfortunately, we are way beyond this point. We are now trying to figure out why there was insufficient lubrication which took out all the connecting rod and main bearings.

 

 

 

12,000rpm??

[baylensman]

GM uses reclaimed metal on many of there crank and rod ends and bearings, subject to deformation under extreme conditions. A bearing moving may close an oil port.

 

While pressure may be right on, the question is at what volume? The standard flow rate for the small block pump is between 8 and 12 GPM depending on the application, (truck car ect) and RPM.

 

I know that a dirty oil filter will give a higher than normal pressure reading while at the same time reducing flow.

 

 

At any point was the vehcile operated while on a slant (i.e. left side higher than the right) such as driving across a hill, park sideway in the yard or with two tires in a ditch for an extendied period of time. Oil pump pick up tube may have been sucking air.

[BuddyRich]

uh,,Yea,,, Whenever Owl was in it,it was tilted way over to the left....:rotf:

[Aussie Annie]

:rotf:

[Black Owl]

uh,,Yea,,, Whenever Owl was in it,it was tilted way over to the left....:rotf:

 

Ouch.

I hope you realize that compared to owls, elephants have short term memory....

[Black Owl]

:rotf:

 

:bang head: And you too Annie. Being down under may not provide any shielding what-so-ever.

 

[Power Trippin]

I guess if its that bad, your most likely looking at either getting a used engine or a new short block. Also, don't forget about your oil cooler. It may be plugged with debris, better off replacing it too.