Engine noise help 5.4L
Thread Starter
sapirtheman
Joined: May 2011
Posts: 1
Likes: 0
From: NC
Engine noise help 5.4L
Hello to all hope weekend is going nicely. I have a 2002 F150 step-side that now sounds like a machine gun. I have been told by a mechanic who happens to be a friend that there a roller or bearing that has gone bad that is now causing a rod to extend down and hit the oil pan and that is what is cuasing the noise. Engine has 125,00o miles on it. He suggested i find new/used engine and replace it. Also said that bc of my truck being step side single cab that i have to keep with the L code vin engine otherwise another engine would not fit because of clearance issues. Like many others on this site I love my truck. I thank all this in advance for for there help.
Senior Member
Joined: Nov 2010
Posts: 534
Likes: 26
From: Coe Hill, ON
There's actually a lot of clearance between the rod and the pan-I doubt they could ever meet and still have the engine run!!! If it is knocking from the lower end-the rod is more likely hitiing on the crankshaft because the bearing (not roller bearing) has worn. But beware: broken exhaust manifold studs can cause exhaust leaks that can and have been diagnosed as engine knocks. I'd check for broken studs-especially near the back-and cracked manifolds.
Senior Member
Joined: Feb 2011
Posts: 2,061
Likes: 25
From: MD
The rod will never hit the oil pan unless it breaks and spins around like mine did in the motor I bought my truck with 
It also had a fist sized hole in the side of the block though.
If it's a rod bearing knock it will get quiet on acceleration and loud while the rpms float down when you release the throttle and if it's a main bearing it will knock when you hit the throttle. To check the rod bearings you can unplug the coils one at a time at idle and if the sound goes away that's the rod with the bad bearing.
Like udderbrudder siad you should check your manifolds for leaks, I don't really see how you could mistake that for an engine knock but hey. And if it comes down to it a compression test will tell you what you need to know about the motor.
BTW rod bearings can often be replaced in vehicle so if you want to just replace one bad rod bearing you can and then just ride it till another one goes. Cheaper and easier than doing a whole motor.
It also had a fist sized hole in the side of the block though. If it's a rod bearing knock it will get quiet on acceleration and loud while the rpms float down when you release the throttle and if it's a main bearing it will knock when you hit the throttle. To check the rod bearings you can unplug the coils one at a time at idle and if the sound goes away that's the rod with the bad bearing.
Like udderbrudder siad you should check your manifolds for leaks, I don't really see how you could mistake that for an engine knock but hey. And if it comes down to it a compression test will tell you what you need to know about the motor.
BTW rod bearings can often be replaced in vehicle so if you want to just replace one bad rod bearing you can and then just ride it till another one goes. Cheaper and easier than doing a whole motor.