Topic: engine Clacking under load - oil pressure dropping over time - or no pressure

[bestos]

Hey guys,

got my jeep - when i start motor - engine clacks clacks loud for about 1 full second, then it gets to normal noise.    As I accelerate and let off to change gears, the Clacking is very prevalent.

the newest development in past month - oil pressure at startup is 65 psi - but after 20min while driving it is at 40psi (15w-50 oil at the moment) under normal speed.  at idle the pressure reads at 25psi once engine is been running for those 20 min. 

Sometimes oil pressure drops to zero and even on STARTUP the pressure is at zero on the meter, sometimes is jumps to 65 psi. 

last time i checked it when it started on zero psi, i took off sensor and hooked up my manual gauge and it is around 20 psi.  so sometimes on startup, I am not even getting full pressure. 

is this bad crank bearings or bad cam bearings (or both) or some bad oil pump or combination of all? 

I can hear the oil leak back down every time when motor is off, but I am concerned with pressure. 

121,000 miles

[cman]

I put a new oil filter on it and see it that helps
And why you running that oil

[sharpxmen]

10w30 is the correct oil, 5w if you live where it's really really cold

if it is clunking and you have oil pressure issues i am going to guess that at least a crankshaft and bearings (both mains and rods) will be required. 20psi is low esp with that oil but it is not extremely low but then again it's when you say it has no pressure at all that should be concerning.

if the oil runs back out of the main galley then at least the oil filter should be changed, i would also maybe save the oil after a change and run it thru a filter paper - it can tell you a lot of what's going on in there (you can also cut the oil filter for that purpose as well and inspect the filter element)

[bestos]

we have had the warmest winter since my childhood - so cold is no issue here in MD this year.  I am running 15W-50 because I was told by a couple old guys, if you have dropping pressure, heavier oil, helps keep the pressure up.  with 10-30, the oil drops from 65psi to 25 in about 10 min.  with the 15-50, it takes near 30min.  it seems better with that heavier oil, it really does.

i have had 2 oil changes done in the last 2 weeks, with 2 new filters, mopar.  I did a new seal on valve cover.