Ever since I blew a headgasket due to the thermostat sticking shut that I've been having problems with the oil pressure. I checked the oil pump screen before I put the oil pan on and it looked fine; the oil pump only has 30k miles on it. I don't know if the oil pressure sender is bad, the oil pump is going, the pickup tube might have gotten partially blocked, or something else. I only have a few hundred miles on the oil and filter.

When I start up my truck cold the oil pressure reads around 40. After it gets up to operation temperature and I drive it for another 10-15 minutes I notice that the pressure reads a little lower than 40. If I slow down or come to a stop the low oil light will come on at around 700 rpms. A few minutes later the needle will start to flicker and after that the oil pressure will just go from around 30 psi to zero. If I give it gas to increase the rpms up one or two hundred, then the pressure goes back up to about 35 psi. I checked my oil and it's fine. I find it strange that it reads low pressure only at idle rpms after I've driven it for 15-20 minutes. I'd appreciate any input on what the cause might be.

 

Have you checked the oil level? I know you only have a few miles on it but it could be burning it or pumping it some where it's not supposed to be?

 

it sounds like some clearances got bigger, or the pump is a little sloppy. i would just throw in some 20-50w and call it a day.

 

^ me too. i'd also add a pint of old fashioned STP.

 

I periodically checked the oil level and it was always in the safe zone. I did have an oil leak which I believe was coming from the oil pan since some oil was hitting the crank pulley and splashing the underside of the water pump. I haven't seen any drops on the ground so unless I'm leaking oil when I'm driving, I don't know where any could be going. I added some since it was closer to the add mark but it read low oil even when the oil level was fine. I don't know if the extra coolant in the oil messed up some of the engine tolerances in the bearings or the oil pump due to the coolant ruining the viscosity and lubrication of the oil. I should check my spark plugs to make sure there isn't any oil on them or that I'm not burning oil.


I will probably try this and see if that helps I just don't want to use a bandaid solution to cover up the problem since I will be selling it sometime this summer. It may work though.

 

i dont know if i would call it a bandaid, considering the proper fix is an entire overhaul. when engines get older and wear out they need a thicker oil, wether the aging was natural or accelerated..... its life.

 

Funny that this would come up today as I recently had the same problem at idle, or coming to a dead stop. I had a guy I know replace the pump with a melling hi volume pump as I was laid up with a bad back and he did the bearings as well and it had good pressure and everything was fine...till last week. I developed a bad leak at the rear of the pan which I am sure is the rear main seal. And today my low oil pressure issue came back. I know dodges run very low oil pressure at idle but it bugs me to have my truck "not right". I am at the point where I may just do the same thing, put in heavier oil and look into getting a new motor. It does have about 190,000km on it but am surprised I am having this bad of luck with the motor so far. I have heard of a 2nd gen running about 400,000 km on the same timing chain. I am thinking a crate motor from Mopar, but I don't know yet. Anybody in Western Canada know a good engine reman place?

 

I have a 1997 Dodge Ram 1500 4x4 5.9 liter which I got sumerged in a nice hole and got water in the engine. I immediately dumped the oil from the engine and replaced it 5 more times. I continued to get low oil pressure so I replaced the oil sending unit. I still got low pressure so I replaced the oil pump and the pick up tube and still read low oil pressure. I purchased a aftermarket guage for oil pressure and it picks up 40 at the start and aroun 5psi after warm up. Funny thing is I have no loss of power and I have no smoke. I heard it could be picking up low pressure from to much clearance between the main bearing and the crank shaft. Does anyone have any thoughts?

 

Well that's exactly what the problem is, the mains and/or the connecting rod bearings are wearing out.

 

my advice is the same as i wrote in post #3