17' 5.0L cold start knocking
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Joined: Jul 2018
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17' 5.0L cold start knocking
Hey all, this is my first post here. I have a 17 5.0 with around 13k miles.. After changing my oil about a month ago ( i always use motorcraft oil and filter) i noticed on a "cold" start after sitting my truck will make a light knocking from the lower end of the engine towards the drivers side. It is pretty loud but it only last for about 10-20 seconds after cold starting and then it sounds fine. Anyone experience anything like this ? I know the 5.0's are loud and ticky engines but this is definitely not the typical injector tap. Thanks for any input!
Senior User
Joined: Nov 2001
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From: Warner Robins, GA
I probably won't be a lot of help, but here goes....once several years ago I changed the oil in my 2005 4.6 and as soon as I did I too started having more of a very noticeable tapping. MC oil and filter. It would only do it for a few seconds then clear right up. Had several people listen to it and got suggestions and answers from the full spectrum of don't worry about it to rod knock. Finally had a GM tech of all people tell me it could be a bad oil filter. The check valve in it was maybe bad and letting all the oil leak back into the crankcase between starts. Being it was cheap and easy, I swapped oil filters...with another MC. My tapping on start up went away. I've since had folks tell me that oil filters don't really work that way, but no denying the outcome of my results. Your mileage may vary. Good luck.
Cargo Master
Joined: Jan 2017
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if its a pushrod engine, what might be happening is the back flow valve in the filter is letting oil drain back so when you start the engine it takes a moment for the lifters to pump back up which causes a tick or tap sound. usually it only takes a few seconds though. just a guess as im not familiar with your engine
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Joined: Sep 2016
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if its a pushrod engine, what might be happening is the back flow valve in the filter is letting oil drain back so when you start the engine it takes a moment for the lifters to pump back up which causes a tick or tap sound. usually it only takes a few seconds though. just a guess as im not familiar with your engine
Since it started after your oil change, I'd replace the oil filter with a Motorcraft, and see what happens.
It could be piston slap, although I don't like guessing at noises that I didn't hear. Newer engines have shorter piston skirts and different piston alloys (than earlier designs) for fuel efficiency, and it makes them more susceptible to slap. It doesn't take much clearance, just a few thousandths. As it warms up and clearances tighten, it usually goes away quickly. If it doesn't go away quickly, then it will cause oil consumption, as it wears a divot into the cylinder wall from the frequent impact.
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