I have a 2.3L ford ranger that has developed what sounds like a lifter knock, however it is completely random. Sometimes it knocks at start up, and other times it won’t knock at first but after 20min. of running it will knock. I have tried flushing the engine, changing the oil, adding thickeners, and checking oil level often. I checked the EGR and it seemed to look clean and responded to a quick burst of air. The only other ideas I can think of would be like the map unit. Nothing to me makes sense due to that the knock is so random. Thanks for any ideas. This is my work/college truck currentently.
Maybe you have a weak and intermittent valve lifter. Sometimes they get sticky and flushing or an additive such as SeaFoam may help or it may not. Other times the lifter must be replaced; in full sets is the proper way.
Once removed visual inspection of the lifter ends(a magnifying glass is necessary sometimes to examine for microscopic pitting) may show a problem or a problem may be noticed by squeezing the lifter between the thumb and forefinger. There should be very little give in it.
I have tried seafoaming it, and engine rinseing it but that seems to actually make the problem worse. These do have problems with the oil pumps however because it is so random I didn’t think it could be wear and tear or a given out oil pump. I do thank you for all the ideas I can get.
The oil pick-up may be restricted by oil ash. For some reason several Ford engines of that period were prone to flash oil into a hard ash which dropped into the pan in small chips, eventually accumulating enough to be pulled into the pick-up screen and severely restricting oil flow and reducing oil pressure. Valve lifters with excess clearence will quickly get noisy with low pressure. That engine will actually drop cam followers.
The only reason that I wouldn’t think that oil ash is the problem is that I ran multiple engine flushes and I also have done multiple seafoam treatments quickly followed by an oil change. I would hope that would help to clean up the oil screen…? The only reason I am weary about replaceing the screen for then I must (bascially) remove the engine to drop the pan, and in that case I should just go and replace the oil pump in case that is the problem… ?