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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: team39763 on September 22, 2009, 05:23:01 pm
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My dually has been having really low oil pressure according to the gauge. I haven't manually tested the pressure with a mechanical gauge yet, but I plan to. I'm not sure how long the pressure has been reading low, it may have been like that since we bought it. While driving along at 2100rpms, the pressure usually is 35-40psi. When we come to a stop it drops to maybe 10psi. The oil looks good, the motor sounds fine, never smokes, the temps are normal. I was told to try thicker oil, so I did and it marked the same. I was told to try 50wt next. If it turns out that my gauge is correct, what should my next step be?
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i have heard 10psi per 1000rpm..
i personally dont like that rule of thumb..
i have read stock oil presure at 800rpm should be 18psi...
i would get a cehap gauge from autozone...etc and double check it.
IMO its too low to effectively lube everything... i run 10w40 with HV pumps evg hot is 22-30psi on my block and idle ranged between 500-1000rpm. 60psi ar 2500rpm
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That is normal for a stock setup.
7 at idle and a pound for every 1000rpms is the general rule for minimum pressure.
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Ok, so it's not in bad shape then. I'll still run a check on it to make sure my gauge is reading correctly.
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That is normal for a stock setup.
7 at idle and a pound for every 1000rpms is the general rule for minimum pressure.
IMO if your running min pressure your looking for trouble... but thats me ona DD aplication..
i know guys that only run 2.5-3qt of oil in a drag application.. since then shut down after the line.
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I think it only goes to minimum at idle. During cruising it's around 40psi or a little less, so it's not too bad right. I was too distracted to mess with the dually today...my race truck is alive once again. I'll get that mechanical gauge on there next week.
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Just wanted to update this and let ya'll know that I fixed the problem by fixing a crankcase ventilation problem. I put 2 breathers on the driver side valvecover and the squeaking/squealing went away and the oil pressure is much better. Always at or above 30 and over 40 at cruise.
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Specification:
Oil Pressure (Fully Warmed Oil not Hot)
10 psi at 600 rpm
25 psi at 2000 rpm
If below specification 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 and measure the engine oil pressure.
If the engine oil pressure is below 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
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Like alot of FSJ guys say, stock gauges are for entertainment purpose only.... get a real gauge, Aftermarket electric gauges are great nowadays, and no worries about hot oil spraying in the cab from a broken line.