Ford introduced the modular engine (4.6 liter) in the 1991 Lincoln Town Car. A multitude have been produced since, in a 2, 3 and 4 valve per cylinder arrangement and in various displacements. They are popular as 4.6 liter and 5.4 liter, in Ford and Lincoln cars, SUV vehicles and trucks.
The Ford Modular engine is well designed, but very "picky" as to the lubrication and oil filter
Originally 5W30 was specified, later Ford changed to 5W20 and 5W20 synthetic blend. The oil filter also has a specific anti-drain back valve and for good reason.
We are seeing a good many of Ford modular engines with a costly problem. The timing chains are relatively long. They are supported by plastic guides and kept tight by hydraulic tensioners. With the proper lubrication and oil filter this works very well for a great many miles. Problems begin when improper viscosity oil and substandard oil filters are used.
With a substandard oil filter the engine oil may drain back to the oil pan. The lack of oil pressure means tensioners cannot tighten the timing chains on startup. When this occurs the plastic timing chain guides can be broken.
Symptoms of a broken timing chain guide can range from noise on startup (not always) to rough idle to a check engine light. This engine was fitted with the proper Motorcraft filter in a hope of helping with the problem. Unfortunately it was too late.
When the timing chain guide (1) breaks, the tensioner (2) will attempt to take up the excess slack in the timing chain. The tensioner piston extends out and the chain is pushed tight. Moving this slack to one side of the chain also causes the cam sprocket (3) to rotate.
Rotating one cam sprocket disturbs valve timing on that bank. This can cause a rough idle can set diagnostic trouble code (DTC) P0300 and codes for lean and rich operation. Many times these engines come to us, after having been mis-diagnosed elsewhere. Needless part replacement has often been a further waste of money. Repair involves timing cover removal and replacement of the chains, guides, tensioners, etc.
Timing chain problems can be greatly decreased by a few simple steps
Use the 
