I have a 99 D with a 5.2. Its been running good til lately. Anyways now when it first starts up the Oil Pressure jumps to 80 until the engine warms up, then it goes back down to 40 and remains at 40. After a long drive it will go to 0 and the gauge lights will come on at a stop sign. When it hits 0psi it doesnt make any noise or anything it still runs great. I replaced the Oil Sending Unit about 6 months ago and that solved the problem the first time. Anyways I just replaced it again and the issue remains. Anyone have any ideas?

 

I'm tempted to suggest you replace the oil pump. Zero oil pressure isn't something you want to fool around with.

My concern is that you said a new sending unit fixed it the first time. If the problem was a bad oil pump, it shouldn't have. Still, if it were my truck doing this I'd be putting in a new pump just for peace of mind if nothing else.

I'd probably also try flushing the oil system with Seafoam (instructions are on the can) in case you have any blockages. When I do this I like to do 2 oil changes. Seafoam in old oil, drive a few miles to let it do its thing, then change oil. Drive normally for a few days, then change oil again to pick up any additional crud that's worked loose. New filter both times, I sometimes use an el-cheapo on the first oil change since it's only on there for a few days.

I'm sure there are other things you need to look at, as well. That's what I've got off the top of my head without any coffee in me yet. Hopefully others will chime in with some other ideas.

 

To change the oil pump, you need to drop the oil pan. How hard is it to get the oil pan off. If I remember right it has a lot of stuff around it. Is it possible to get the pan off without taking all that other stuff off? Hydrashocker mentioned in another thread to try the PVC valve, but I dont see what the PVC valve would have to do with the oil pressure. Is it possible it really is hitting 0psi, because I would imagine that at 0psi it would really be making some noise or shaking. I wouldnt mind getting that oil pan off though just to see if there is any sludge in there. Thanks for your info, but Im gonna wait for a few more responses before I start doing anything about it.

 

see if you can get your hands on a mechanical gauge to see if you really are loosing oil pressure or not, also i have heard of oil filters clogging up and causing problems similar to this

 

Yeah Im gonna order a sunpro mechanical gauge from amazon and a PCV valve as well since its cheap. Can anyone tell me how to setup the new gauge or point me to a guide. I would like to keep it inline with the stock gauge so I can watch both if it is possible. Thanks

 

also is it normal for the PSI to hit 78-80 at startup till the engine warms up?

 

Yes that is normal. Have you done an intake gasket lately?

 

No I havent messed with the intake gasket at all. Also I wanted to add that i just changed the oil lately with 5-w30, and a k&N oil filter. Could that be causing my problems. I just got the vehicle in July and someone told me to put 5w30 in it. After some research I see it is 10-w30 that is recommended.

 

i would use the 10w30 recommended oil unless you live in a very cold area (then the manual says to use 5w30), so no the 5w shouldnt hurt anything, but the 10w would be best

 

Replace the PCV valve and check your PCV hose. https://dodgeforum.com/forum/1st-gen...-pressure.html

Also ensure that the breather hose that attaches to the back of your air hat is attached.