720 diesel oil pressure issue

[steve duplechin]

My 720 diesel loses oil pressure as it heats up. My gauge will show High pressure and slowly goes down as it heats up. After a couple of hours it will get all the way down to the red area. I am using straight 40wt. oil. What could be the issue? I rebuilt the engine about 12 yrs ago. Thanks for any help.

 

[Scott 730]

Check the pressure with a known good gauge before doing anything else.

 

[jpi72]

I had a similar problem. Are you using oil? In my case the seal on the right side (clutch side) of the main bearing was allowing oil to go into the housing where the live PTO gear is located. Check to see if oil is going into that housing. Good luck.

 

[buickanddeere]

All this sounds familiar . A very similar question was asked recently .
Somebody else who had solved a similar problem . They posted an image of a two cylinder oil pump inlet pickup screen . The screen was loaded with scummy sludge .