Hi the 6.4L diesel engine are common for lifter type noises, this is how they are most often described by customers at my dealer.. There is a ford tsb that I will attach to this post so you can read it. Ford states the noise is normal and nothing to worry about. It is almost impossible to tell you what your exact noise is without hearing it myself but this is the only noise complaint we've seen at my dealership in the past 3 years and we work on these 6.4's everyday. If you feel your noise is more than concern posted I would recommend stopping by your ford dealership and let them listen to it and make the decision. The engine does have a 5yr 100K miles warranty if the noise is something more than this tsb. If you aren't experiencing any driveabilty issue the tsb will most likely apply to your truck.Thanks and please remember to click the accept button as this is the only way I can recieve credit for my time and answer. Thanks
This article supersedes TSB 08-19-5 to update the vehicle model years.
Some 2008-2010 F-Super Duty 250-550 vehicles equipped with a 6.4L diesel engine may exhibit a random engine ticking / tapping noise that is most noticeable when engine coolant temperature is 185 °F (85 °C) or higher and from base idle to approximately 1500 RPM. Some customers may complain that this noise becomes more evident after 3000-5000 miles have accumulated on the vehicle or after an engine oil change.
Refer to the Service Procedure for repair recommendations.
The ticking / tapping noise is most noticeable at the rear of the driver's side front wheel well. 6.4L Powerstroke diesel engines exhibit this normal audible condition (some engines will exhibit greater audible noise due to engine build variations). 6.4L Powerstroke diesel engines are manufactured to tight tolerances in order to meet strict durability and reliability standards.
This noise is caused by the relationship between engine block, crankshaft journals, bearing inserts and oil viscosity / film. This relationship allows a pulsation that resonates through the cylinder block and is heard as a metallic ticking noise. This condition is present on all diesel engines.
Technological improvements and overall noise reduction in today's diesel engines make this issue seem new when in fact it was masked by other noises on previous engines. Other engine manufacturers report similar conditions in their diesel engines. Vehicle testing and engine teardown analysis have confirmed this condition will not effect reliability or long term durability of this engine. Dealers should not attempt to perform vehicle to vehicle noise comparisons. This may lead to incorrect conclusions and ineffective repairs.