2000 Dodge Ram with 100,000 plus miles - 5.9L 360 engine

After replacing the coolant thermostat, bypass hose and water pump I noticed the oil pressure was higher than normal - I suspect somewhere in the 50 -60 pound range while running at highway speed. At idle it would come back down to just under 40 pounds. I had had the oil and filter changed about 500 miles prior to changing the water pump.....

Yeserday I changed the oil pressure sensor (by the distributor) and changed the oil and filter and still have the same issue except now the pressure is not coming back down on the idle. Of interest, when I had put 3 quarts of the new oil in, I started the engine to circulate the oil and noticed the pressure jumped back up to the 50 - 60 pound range.... when all 5 quarts of oil were in, the pressure remained the same - did not increase...... I am using Castrol 10X30 high mileage oil with a mopar filter.

Any help would be appreciated!!!!

 

The numbers you are reporting are actually pretty good. Pressure is expected to increase with RPM, to a point..... (as the oil pump also has an internal pressure regulator, wouldn't want full pressure the pump is able to develop, as that would launch oil filters.... had that happen before on a Honda.... start the engine, oil filter becomes perfectly spherical before blowing itself apart..... I think I may still have on of them. ) New oil will increase pressure as well. Also, the oil pressure gauge isn't exactly accurate..... Mine reads right around 40 all the time, no matter what is really going on. The mechanical gauge told a different story.

 

Wow this is different, we usually get threads about LOW oil pressure not high oil pressure. Your pressure regulator that HeyYou mentioned may be sticking but the pressure is not high enough to worry. I do recommend that you get a mechanical gauge to determine what the pressure really is.

Does the motor make any different noises or run differently? It is possible that an oil passage is blocked and causing the higher pressure.

 

my pressure is high as well.....the needle is past the 0 in 40 when on the gas, and drops to around 45 idle......but ive been experimenting with oils, to see what goes best.....yes flame me if wanted, but i changed from synthetic to conventional because ive been told by numerou people that synthetic is not made for our engines. doesnt clean them right......so i used Castrol GTX high milage conventional 5w30, an now my pressure is like yours.....i use to have 35 idle, and about 45 on the gas......now like i said its 45 idle, and around 60 on the gas.....its NOT a bad thing lol

 

Not quite sure how to reply in this forum/format.....

Engne runs smooth.....no real hiccups.....no difference in performance pre or post oil pressure increase....... I will be hooking a mechanical gage to it tomorrow to see what the pressure is really doing....... kinda a pain in the hip pocket to get to the sensor area but it has to be done!!

Thanks for the response

 

This is a direct quote from OnDemand5.com website. This is a paid website with any and every auto manual.

<quote>
Courtesy of CHRYSLER CORP.

OIL LINE PLUG

1. The oil line plug is located in vertical passage in rear of block between oil-to-filter and oil-from-filter passages. Missing or impropery installed plug could cause erratic, low or no oil pressure.

2. To check installation, remove oil sending unit and insert wire down passage. Oil line plug should be 7.50 to 7.68 in. (190.0 - 195.2 mm) from machined surface of block. If plug is too high, use suitable dowel to position properly. If plug is too low, remove oil pan, oil pump and rear main bearing cap. Use suitable dowel to position properly.

3. To remove for passage cleaning or plug replacement, drive plug from oil sending unit hole out bottom of block. When installing plug, coat outside diameter with Mopar Stud and Bearing Mount Adhesive or equivalent. Plug should be 2.12 - 2.31 in. (54.0 - 57.7 mm) from bottom of block.
<quote/>

 

Next OnDemand5.com article suggests the relief valve is sticking in the oil pump. Stuck open, will cause low oil pressure reading and vice versa.

Fix, rebuild the pump.

Realistically, replace the pump.

 

I would, NOT bother with it, your oil prssure is coveted by many. Thats VERY good pressure and I'm wondering why you would want to alter it...

 

Dude, 50-60 pounds at idle is GREAT NEWS. That means your oil pump is working well, and your engine is getting the lubrication it needs to function. Good oil pressure = happy engine.

LOW oil pressure is when you need to worry

 

NO, why in the hell would you mess with something when there is no problem in the first place?

Brand new engines should run between 35-50 psi. When engines wear out, the oil channels and clearances loosen up, and you loose oil pressure. An engine that won't hold sufficient oil pressure is worthless, and requires a rebuild.

I would LOVE to have 50lbs at idle. It's just an indication that everything is being properly lubricated.