Update…so truck was in again today. My mechanic did not end up going into the oil pan as he said it would be approximately an 8-10 hour job. He did say that the oil pump would be accessible at that point as well but neither would guarantee that my oil light issue would be resolved. His suggestion, due to the fact that my oil pressure was only low at startup and seemingly not causing any other problems was to continue driving the vehicle as is. He did put a thicker oil in it for the spring and summer and said he’ll put a thinner oil in during the winter. Overall, he thinks that for the age of the vehicle and kilometres ( 2005 Dakota, 175000 kms) he would not invest that kind of money when there may not be a resolve. I agreed with him.
I am thinking about just putting the truck for sale and seeing if anyone bites on it. Hopefully I can get a couple grand for it and just put that towards a newer truck.
From the tests that have been run so far and the steps taken by the mechanic. All clues point to the engine needing a rebuild. That Knocking sound upon startup is the crank bouncing around (so to speak) within the plain bearings in the bottom end of the engine. The noise subsides and or goes away when the oil pump is able to get a film of “cushioning” oil established within the bearings in the lower end of the engine. The mechanic more than likely added a product that improves film strength and viscosity of the crankcase oil. This is why the noise has subsided since then. All this is doing is filling in the excessive clearance in the lower end bearings. If and when the oil is drained and changed the noise will return if the same product is not added. ALL OF THIS is strong evidence that the motor has given all it can give at this time… Time for a rebuild for this engine. I have seen MANY modern Mopar V8’s Give up the Ghost by this mileage and even at earlier mileage marks.
I have also seen Many Mopar V8’s that have a lot of sludge when the oil is NOT changed in a proper manner…When oil is left in the engine so long that it literally BAKES itself onto the inner surfaces of the block… then this baked on oil begins to flake off and fall down into the pan clogging the oil pickup screen on the oil pump. When this happens and is severe enough to starve the pump of an easy way to pull up oil to pump thru the motor…The engine bottom end suffers EVERY TIME the motor is started up…things improve while running but upon startup the lower end is essentially running dry for a few moments…(CRITICAL MOMENTS)…and those dry seconds add up and do NO FAVORS to the crank or plain bearings. It just keeps getting worse and worse and the wear or clearance keeps on growing until its time for a rebuild… this is when you can put in an additive in the oil to quiet down that initial knocking sound. Just another audible indicator of excessive wear in the bottom end…
When I built my first VERY SERIOUS Performance V8 (In Excess of 600Hp) I also installed a PRE-OILER to preserve the bottom end. This Pre-Oiler does just what it says…it pre lubricates the engine PRIOR to startup so that the dry start NEVER Occurs and engine life is drastically lengthened…and any oil related failures are headed off at the pass. The Pre-Oiler system has been around almost as long as the Internal Combustion Engine itself ( I believe they were popular in the 30’s and 40’s in Aircraft)…I always LOVED the idea of a Pre-Oiler and used to Daydream about when OEM mfg’s would install them. That day will probably NEVER come if it hasn’t by now. Oh well…they really DO NOT want your engine to last forever…its no fun for the mfg’s. LOL Just a little useless information I suppose…sorry.
Time to Rebuild or Re-Power eventually. You can drive it like this until it gets worse and that may be many thousands of miles/Yrs actually… But the end is Nigh… Sorry for the news
Blackbird
@Shannon11 “2005 Dakota, 175000kms”
Do you live in Canada?
Because if you don’t, your odometer should read miles
In any case 175000km is not high mileage
And a 10 year old truck is not ancient
I found this thread because I’m having a similar problem, also with an '05 Dakota with the 4.7 engine and relatively low miles (93,000). It has only happened twice so far but the oil light comes on shortly after startup and stays on. Engine sounds fine–no ticking or knocking like might be caused by having true low oil pressure. I pull over and shut the car off, check the oil level and it is full. Restart the car and the problem is gone and drives fine for another week. It happened again yesterday and all I did was shut the car off and restart and the light stayed off and ran just fine. I’m thinking the problem is electrical somewhere in the instrument cluster. I think this because of a weird problem I had last year when I was driving down the highway and suddenly every warning light came on at once and my tachometer and speedometer froze. I pulled over and shut the engine off and restarted and everything was just fine and it never happened again. Did you ever figure out the problem?