Back in late June my 2003 F-150 Supercrew 5.4L (144,000 miles)developed the infamous right bank oil leak. While having the headgasket replaced the mechanic noted that the timing chain tensioner needed replacing as well. 5 weeks later a subtle tapping sound (driver side) developed and after a quick visit to the shop it was detemined that it was not the injectors and was the left side tensioner.

Tensioner was replaced this past weekend and the mechanic cleaned the injectors as well. Upon start up it rapped loudly until the pressure came up and then ran as smooth as any new truck. The mechanic accompanied by me then took it for a test drive and he indicated that he needed to clear the carbon out accelerating heavily from a standing start to 70mph about three times.

When we returned to his shop he shut off the engine waited about 5 minutes and restarted the truck to a notable "knock". Lower right (passenger side). Disengaged the injectors one by one and did not hear any difference. Took off the belt and the knocking dropped off significantly. Turned off the engine and he got under the truck and after a few minutes later stated that the crank run out was over a 1/4 inch and the bearing must be shot.

We replaced the belt, restarted the truck and noted the sound had gone away. He explained that most likely the torque convertor had swelled placing pressure on the crank pushing it forward and thereby having the rods out of alignment causing the knocking sound. Since it cooled off, the convertor was no longer pushing the crank forward and the rods out of alignment.

I drove home and before shutting it off noticed that it was quiet. Got up for work for morning and was introduced to my new "diesel" F150. It's about 50/50 over the last 3 days on whether or not it will knock.

My question is, why would it knock sometimes and not others and has every cause for the sound been explored. If so, is my only alternative an engine swap?

Thanks,

Mike

 

TC swell? In all my years I have never heard of such a thing. They only cause of lower end knock would be bad bearings/crank that sort, but you stated that its intermittent, so that puts even more things into the problem.

If by some fluke the TC really were swelling, if it sat overnight, the swelling would go down since the high pressure would bleed off into the tans pan and the trans after the engine stopped, especially after sitting at night.

By my best guess, its some sort of lower end problem that would need the pan dropped and the bearings and such inspected/plastigaged.

ETA: Where you said when you took the belt off it got better, that would point to maybe some sort of over strain the belt is putting on the nose of the crank and pulling it upward ever-so-slightly which would then of course be multiplied by the engine running. Maybe a bent crank, but I still say lower end.

 

Mike, are you sure it's in the bottom of the engine. From what you describe, the rattle you are getting is mostly upon a cold start up. What kind of oil filter are you using. The modular engines require a filter with an anti drain back valve such as the Motorcraft FL-820S.

If you are using a sub par filter, I suggest you change the filter and make sure you are using the correct oil before tearing further into the engine.

 

I have heard of torque converter swell, or balooning... It is in the most severe cases. Here is a example. You put 300 hp shot of nitrouse and run your truck wide open at the dragstrip all day... They have an anti balooning plate, that is welded to converters for that reason. That being said, I doubt you need an anti balooning plate.

I wonder if it isnt something with your cam. Doe your year truck have cam phasers, or was that only on 3v systems.

You can take a section of garden hose about 3 ft long, and use it as a stethoscope. while it is happening, and it will give you an idea.

Is the knock rythmic... like when the engine revs it speeds up? cosistent when happening? or does it fade out then return?

 

Sorry about the delay in responding. To start with oil changes have been at 3000 miles using 5w20 Motorcraft and the prescribed Motorcraft filter since day one with the exception of a couple of oil changes made out of town.

Tried to listen to it tonight and heard the same knocking which changes with the idle but it was softer. I took it on the road and did some hard acceleration and when I came to a light heard it knocking pretty hard and took it home to listen. When I got there it had toned down. I dont know if this has cam phasers or not. I do know that the model is a 99L.

 

No cam phasers until the 04 3V engines.

Sounds like maybe a sticking valve lash adjuster that may be letting a rocker arm knock.

Also, you might want to check the actual oil pressure with a real gauge. The one in the dash is a dummy gauge. Reads a bit over 1/2 when more than 7psi.

 

Well,

This knocking didn't start until after the head gasket was replaced on right side, same side as the knocking. It was steady knocking today and the sound is coming from the right side, forward area of the block on the lower end. I've been to two dealerships and they state that without tearing down the engine they can't be sure what the problem is.


Mike

 

You should pull the valve cover off and give it a lookie loo and see if you see anything bad (i.e. broke, extreamly loose, missing, etc) just compare it to the others, and if your still not sure, pull the other sides cover and compare it then since it sounds like your saying its just coming from the one side.