“Low oil pressure” I’m stuck...

[cam3439]

If the oil pump pickup tube o-ring was nicked during installation, then it could caused those issues. This assumes the correct o-ring size was installed. Different oil pumps/tubes call for different size o-rings.

 

[retiredsparky]

For an older engine, with higher clearances, increasing viscosity to a 10-30 oil is ok. Are you using 5-20 viscosity?

 

[Rocket Man]

You didn’t specify if the pressure was the same before you changed the oil pump. I can only assume you changed it because of low pressure? Was there any difference at all? I suggest sending an oil sample off to Blackstone Labs for analysis while you work on this issue, just to see how much wear is happening. Also like mentioned, there’s different o-rings so when you installed the pump are you sure you used the right one, and exactly what pump did you use? Melling has 3 different pumps for these engines and you should have gone with the high volume high pressure one I believe due to your mileage.

 

[CDLute138]

If the oil pump pickup tube o-ring was nicked during installation, then it could caused those issues. This assumes the correct o-ring size was installed. Different oil pumps/tubes call for different size o-rings.

I didn’t see any nicks but I won’t rule it out


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[CDLute138]

For an older engine, with higher clearances, increasing viscosity to a 10-30 oil is ok. Are you using 5-20 viscosity?

I am currently using 5-20, 10-30 wouldn’t be a bad route to go


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[CDLute138]

You didn’t specify if the pressure was the same before you changed the oil pump. I can only assume you changed it because of low pressure? Was there any difference at all? I suggest sending an oil sample off to Blackstone Labs for analysis while you work on this issue, just to see how much wear is happening. Also like mentioned, there’s different o-rings so when you installed the pump are you sure you used the right one, and exactly what pump did you use? Melling has 3 different pumps for these engines and you should have gone with the high volume high pressure one I believe due to your mileage.

Pressure was actually lower before changing the pump, it definitely went up. I am using a melling pump but can’t for the life of me remember if I bought the high flow, I’m gonna dig through my paperwork and see if I can find it...that may just be my solution...


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[iamdub]

If you can rule out anything malfunctioning, worn or damaged (sensor, O-ring, etc.), then the only other cause would be excessive bearing tolerances. Nothing you can do about that but rebuild or replace the short block. IMO, the pressure isn't low enough to go there yet. I'd focus on increasing the pressure just to keep the warnings off and not worry about it. First step is to quit using lizard piss, the 5W-20, as your lubricant. Use 10W-30 at a minimum. I use four quarts of 5W-40 and two of 15W-40 Rotella T6 in mine to give it more viscosity than 5 but not as heavy as 15.

Are you the original owner? Do you know if it has always had 5W-20 in it?