Hey guys,

First time posting here. Love the site and feeback everyone is providing. Maybe you can help me with my problem. I bought this '96 F350 7.3L dually a couple of months ago. When I bought it, I did not notie this problem as it seems to be getting progressively worse.

I am hearing a loud knocking right around the rear cylinder next to the firewall on the drivers side. When I listen with the stethoscope it can be heard just above the valve cover on the block but also very noticeable from underneath on the block below the same area. Checked around the rest of the block for this noise and can't find another area that is as distinguishable. The noise has progressively gotten worse over the last couple months. Very loud in the morning at idle and during driving but quietens as she warms up. This truck does not show any black or white smoke, runs relatively good with no noticeable hesitations. She only has 106000 miles. Did oil, fuel filter, air filter change since purchased. Getting about 14 miles per gallon. 4.10 gear ratio


This is what I have done to diagnose the sound.

Ran the computer on it. All passed except for Cam position sensor code. I doubt this is the issue and will replace shortly.

Thought it may be a lifter, connecting rod or valve?? Took the valve cover off and started the motor to see. everything seems normal with all components ticking away. Definetly not the loud knocking/ticking. This noise is to the same timing as the crankshaft revolution, not the camshaft, as the lifters are moving at half time to the crankshaft.

Maybe a faulty injector?? I pulled the injector electric connector lead and although runs rough, the knocking is still there although not as noticeably loud.

Took an oil sample and sent it in to Finning for an oil analysis. Results came back stating the oil did not have any metal or dirt contaminents abnormal for this engine.

Spoke to 4 different mechanics who are unable to diagnose anything that doesn't read on a computer. Although they definetly hear it, all have told me that I should continue to drive it until it progresses into a larger problem that can be more easily diagnosed!! Well, I could diagnose it too at that stage.

I am dreading that it may be a bottom end problem, connecting rod wrist pin maybe, anyways, potentially something that may require a rebuild.

If anyone has any suggestions that I haven't tried or thought of, please let me know.

Thanks.

 

Welcome to Ford Truck Enthusiasts PG Stroker.

It sounds more like an injector to me than anything else. Maybe try an injector cleaner. Lucas, Stanadyne, or Power Service all work pretty well. Just make sure you don't use any of the gasoline fuel addatives as they contain alcohol and are very bad for your injectors.