Dull, Rythmic Thud
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Joined: May 2005
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From: Fort Worth, TX
Dull, Rythmic Thud
A few questions about the new truck
Truck is an 02 5.4 with 68xxx miles. My main concern is a dull, rythmic thud that I (but no one else, I am extremely picky) can hear under certain conditions. It is most obvious on a cold start-up when the engine is idling higher than when warm. Like I mentioned, I hear it mostly at cold idle, but can duplicate it by revving the engine slightly and the thud is heard as the engine is idling back down, most obvious at 1000 RPM or lower. My completely uneducated theory is that one of the cylinders isn't hitting as hard as the rest causing a very slight unbalance under just the right conditions. Makes sense, but it is just SWAG. I can only detect the noise in the cab with the radio off, windows up, and blower speed off/low. Standing in front of or around the truck I can't hear it--hood up or down. Idle is smooth(not rough, but sometimes fluctuates momentarily when engaged from gear into neutral when cold) and engine is silky smooth when driving at any speed. To describe it the best I can I would say it sounds somewhat like V-8 exhaust pulses, but slower.
Any ideas? More than likely this is a minor detail that I will just have to live with but I'm open for suggestions. It would make me feel better to know of any others who experience the same thing, though
Thanks,
Brian
Truck is an 02 5.4 with 68xxx miles. My main concern is a dull, rythmic thud that I (but no one else, I am extremely picky) can hear under certain conditions. It is most obvious on a cold start-up when the engine is idling higher than when warm. Like I mentioned, I hear it mostly at cold idle, but can duplicate it by revving the engine slightly and the thud is heard as the engine is idling back down, most obvious at 1000 RPM or lower. My completely uneducated theory is that one of the cylinders isn't hitting as hard as the rest causing a very slight unbalance under just the right conditions. Makes sense, but it is just SWAG. I can only detect the noise in the cab with the radio off, windows up, and blower speed off/low. Standing in front of or around the truck I can't hear it--hood up or down. Idle is smooth(not rough, but sometimes fluctuates momentarily when engaged from gear into neutral when cold) and engine is silky smooth when driving at any speed. To describe it the best I can I would say it sounds somewhat like V-8 exhaust pulses, but slower.
Any ideas? More than likely this is a minor detail that I will just have to live with but I'm open for suggestions. It would make me feel better to know of any others who experience the same thing, though
Thanks,
Brian
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Joined: Oct 2001
Posts: 127
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I agree that these engines can make some troubling noises. We have two F-150's (1999 and 2001) with 5.4 and they are both high mileage - one over 100,000 and the other approaching. They have both made intermittent - and maybe that is the key work here - knocking noises that no one wants to hear on start-up.
It probably happens more in the winter. So far, both trucks have been pretty much trouble-free and I really don't think the bad start-up noises are a problem.
My advice is to not ignore the oil changes and use the right Motorcraft filter. Otherwise, the noise is probably not a problem.
It probably happens more in the winter. So far, both trucks have been pretty much trouble-free and I really don't think the bad start-up noises are a problem.
My advice is to not ignore the oil changes and use the right Motorcraft filter. Otherwise, the noise is probably not a problem.