help..loud knock
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help..loud knock
Hello i need some advice. My 5.4 L has developed a knock. At first i was suspecting it was a rod bearing, but today i had a friend give it throttle while i held a pipe to the engine and the other end to my ear. I noticed that I cannot hear the knock in the oil pan/ bottom end of the engine. But if you place the pipe on the valve cover you can hear it verry well. What scares me is that it is not a normal valvetrain tick , it is a very distinct and loud knock. Any and all help is greately apeciated.
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Joined: Sep 2013
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From: Edmonton, AB
What type of vehicle are your driving? F-150 F-250? Expedition??? That info will help.
Now you say there is a knock, but is this knock starting as soon as the vehicle is started? Is this knock occurring when the engine has warmed up? Is the knock there while being driven on the hwy? Does the knock only happen at higher RPM's than what you would see at at idle with the vehicle in park?
Really the more information you can share in detail will give us a better chance of understanding what the symptoms are and when they are occurring , so hopefully we can give your some better answers on things you could check and see thru the process of elimination.
Now you say there is a knock, but is this knock starting as soon as the vehicle is started? Is this knock occurring when the engine has warmed up? Is the knock there while being driven on the hwy? Does the knock only happen at higher RPM's than what you would see at at idle with the vehicle in park?
Really the more information you can share in detail will give us a better chance of understanding what the symptoms are and when they are occurring , so hopefully we can give your some better answers on things you could check and see thru the process of elimination.
Thread Starter
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New User
Joined: Feb 2016
Posts: 17
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What type of vehicle are your driving? F-150 F-250? Expedition??? That info will help.
Now you say there is a knock, but is this knock starting as soon as the vehicle is started? Is this knock occurring when the engine has warmed up? Is the knock there while being driven on the hwy? Does the knock only happen at higher RPM's than what you would see at at idle with the vehicle in park?
Really the more information you can share in detail will give us a better chance of understanding what the symptoms are and when they are occurring , so hopefully we can give your some better answers on things you could check and see thru the process of elimination.
Now you say there is a knock, but is this knock starting as soon as the vehicle is started? Is this knock occurring when the engine has warmed up? Is the knock there while being driven on the hwy? Does the knock only happen at higher RPM's than what you would see at at idle with the vehicle in park?
Really the more information you can share in detail will give us a better chance of understanding what the symptoms are and when they are occurring , so hopefully we can give your some better answers on things you could check and see thru the process of elimination.
F-150 It starts as soon as it is started. It does it when its cold or warm. The only difference is that its not nearly as loud at idle but its still there. It gets loudest around 2000-2500rpm after that it gets a littke quieter. And it is coming from around the number 3 and 4 cylinder area.
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Joined: Sep 2013
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From: Edmonton, AB
Ok I am going to ask some basic questions. When did you do your last oil change? What brand oil filter did you put in and what type of oil 5w10? 5w30? How is the oil level in the truck? How is the oil...clean? Dirty? I am sure you know oil loses it's viscosity hence the Oil questions.
Have you checked your oil pressure? There is always a possibility of the Oil pump starting to fail, but Usually you'd hear some lifter noise but there is always a possibility of an oil pressure issue?
ok let's see if we can try and narrow it down. What you may want to try is disconnecting one COP and one injector per cylinder and see if it eliminates the issue.
What your doing is going thru a process of elimination, so you would unplug your cop and injector and then start up the truck and see if doing that to each cylinder changes the knock ( obviously this is just a suggestion)
It's just to see if we can narrow down that way to a cylinder. I would give that a look and let us know the results
Have you checked your oil pressure? There is always a possibility of the Oil pump starting to fail, but Usually you'd hear some lifter noise but there is always a possibility of an oil pressure issue?
ok let's see if we can try and narrow it down. What you may want to try is disconnecting one COP and one injector per cylinder and see if it eliminates the issue.
What your doing is going thru a process of elimination, so you would unplug your cop and injector and then start up the truck and see if doing that to each cylinder changes the knock ( obviously this is just a suggestion)
It's just to see if we can narrow down that way to a cylinder. I would give that a look and let us know the results
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New User
Joined: Feb 2016
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Ok I am going to ask some basic questions. When did you do your last oil change? What brand oil filter did you put in and what type of oil 5w10? 5w30? How is the oil level in the truck? How is the oil...clean? Dirty? I am sure you know oil loses it's viscosity hence the Oil questions.
Have you checked your oil pressure? There is always a possibility of the Oil pump starting to fail, but Usually you'd hear some lifter noise but there is always a possibility of an oil pressure issue?
ok let's see if we can try and narrow it down. What you may want to try is disconnecting one COP and one injector per cylinder and see if it eliminates the issue.
What your doing is going thru a process of elimination, so you would unplug your cop and injector and then start up the truck and see if doing that to each cylinder changes the knock ( obviously this is just a suggestion)
It's just to see if we can narrow down that way to a cylinder. I would give that a look and let us know the results
Have you checked your oil pressure? There is always a possibility of the Oil pump starting to fail, but Usually you'd hear some lifter noise but there is always a possibility of an oil pressure issue?
ok let's see if we can try and narrow it down. What you may want to try is disconnecting one COP and one injector per cylinder and see if it eliminates the issue.
What your doing is going thru a process of elimination, so you would unplug your cop and injector and then start up the truck and see if doing that to each cylinder changes the knock ( obviously this is just a suggestion)
It's just to see if we can narrow down that way to a cylinder. I would give that a look and let us know the results
The oil is clean and was just changed about 200 miles ago using castrol 5w-20 as recomended in the manual along with a motorcraft filter. The previous owner changed the oil religiously. About every 2 months reguardless of mileage. I do not have an external gauge for the oil pressure though i am looking ito it. The in dash gauge is reading normal. I went cylinder by cylinder a few weeks ago and unpluged each cop and injector one by one but did not change anything other than the idle from cuting that cylinder. I also have all new coils and plugs on about 2 months ago. I did this due to the suspected rod bearing. This was before i realized it was coming from the top end and not the bottom.
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Posting Guru
Joined: Sep 2013
Posts: 1,348
Likes: 6
From: Edmonton, AB
Well that is good to know. Next step after the oil pressure would be to take off the valve cover and see what you can spot. That would be the next step I would think
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