2001 Ram 5.2L 170,000 miles. I bought it used in last year. Oil pressure drops to zero after running it for 30 mins or so.


So I have had the oil pressure problem for a while. The 1st solution was to do the Plenum fix. That is done about 4 months ago. Still had the problem. 2nd fix was to replace the oil pump and clean out the screen. That is done and the screen was clogged. Still had the problem. 3rd fix was the sending until. It was cheap so I just replaced it. Still had the oil pressure drop. I decided to put 20w 50. This helped but after about 30 mins of driving it still happened. So.... the last thing was the bearings. I just replaced them tonight. Mains and rods. The mains were showing copper and rods were not that bad. Started it up and drove for 30 mins and the same damn thing! Oil pressure dropped to zero. Am I out of options here? Do I need to run 20w 50 all the time? I live in Florida so it won't be a problem doing that. I put 10w 30 in tonight. Not sure what else to do. Thanks

 

Welcome to DF. Don't have any ideas except the things you have already tried. Might want to put a mechanical gauge in and run it to make sure the pressure is really dropping? Does the engine rattle when it drops to 0?

You can download service manual here to see if anything ther can help: 2nd Generation Dodge Ram Service Manuals

 

Mechanical gauge FTW.. +1, in other words.

 

Yeah the factory gauges are often faulty.

 

No rattle... Truck runs great. Gonna try the gauge this weekend and go from there. I have been trying to trouble shoot this for a while now.

 

Ya I think your engine would be making some funny noises and shaking if it really had no oil, you would also see the temp gauge go up and the speedometer go down pretty quickly if you kept your foot on it

 

+1 on gauge

 

Ok... update. Hooked up the mechanical gauge this afternoon. Had a T fitting on it so I could see the electronic gauge as well. Drove it around until it got nice a warmed up. Sure enough the factory gauge dropped to zero at idle and the mechanical gauge stayed at 9 psi. Never dropped below 9 psi. It was about 20 psi when running on the highway. Soo... my pressure is fine. I read somewhere the sending until needs to read atleast 10 psi or it will think there is no oil pressure and the gauge will drop to zero. But the service manual states 7 psi is minimum at idle. I think I am going to run some Seafoam in it then switch to 20w50. Also something I noticed was if I take it out of gear the RPM's go up a tick the the pressure goes to 11 psi. Then the factory gauge is fine. Now am I out of options?

 

i have a 2001 dodge ram with the 5.9L and when running at 75-80mpg 2100 rpms my factory gagues readys 45 psi of oil.... it seems like 20 psi is pretty low my truck at a idle still has about 25-30psi and i use 10w30 Pennzoil full syn

 

If seafoam doesn't help you could try something like rislone. If those don't help just install the mechanical gauge and call it a day