The Ford GT (supercar) and a few of Ford's other performance vehicles are specified to use 5W-50 synthetic (The GT is specified to use Castrol Edge Supercar 5W-50 specifically in the owner's manual, but it meets a Ford specification). That got me thinking, so I looked up the VVT solenoids from the GT and they are common with Ford's other engines (2.3L, 3.5L, 5.0L, etc...) It seems to me that mechanically speaking, the 5W-50 synthetic would run in the majority of Ford's engine lineup. I remember Ford Australia's modular V8s (which were made in the US) being specified to use a 5W-50 synthetic while the same engines in the US were spec'd to use 5W-20.
The reason for me asking is that it looks like the internal water pump on the Duratec V6s (3.5/3.7) have a non-sealed bearing that relies on engine oil to lubricate the needle/ball bearings. Someone used a water jet to cut apart the failed water pumps and saw flat spots on these bearings. I'm thinking the bearings probably failed due to a lube issue, causing the shaft to overheat and destroy the shaft seal, causing the coolant to flow into the engine oil. Since the majority of these engines are running 5W-20 or 5W-30 as well as in police fleets with 50k water pump changes, maybe those oils aren't providing enough protection? There are lots of reports of timing chain "stretch" (basically wear) on these engines as well. I have a friend whose Explorer Sport (3.5L EcoBoost) with under 50k miles had to have the timing chains replaced due to "stretch".
The reason for me asking is that it looks like the internal water pump on the Duratec V6s (3.5/3.7) have a non-sealed bearing that relies on engine oil to lubricate the needle/ball bearings. Someone used a water jet to cut apart the failed water pumps and saw flat spots on these bearings. I'm thinking the bearings probably failed due to a lube issue, causing the shaft to overheat and destroy the shaft seal, causing the coolant to flow into the engine oil. Since the majority of these engines are running 5W-20 or 5W-30 as well as in police fleets with 50k water pump changes, maybe those oils aren't providing enough protection? There are lots of reports of timing chain "stretch" (basically wear) on these engines as well. I have a friend whose Explorer Sport (3.5L EcoBoost) with under 50k miles had to have the timing chains replaced due to "stretch".