4.0 SOHC Radiator Cap Swap

[JohnnyO]

Later model 4.0 SOHC engines have a 20 lb radiator cap. This is probably too high because they tend to get cracked thermostat housings and radiator tanks. Pro Tip: Swap to the 16 lb cap spec'd for a 1998-2000 Mustang V6 and t-stat housing and radiator failures are less likely to occur.

 

[sgtsandman]

One solution to combat the thermostat housing issue is to get an aluminum one to replace the plastic one that comes with the engine. Though, the radiator cap idea isn't a bad one either.

https://simmonsautosportz.com/products/2006-2010-ford-ranger-metal-thermostat-housing

 

[sgtsandman]

I just looked up the cap for the 2011. Ford Parts lists a 16lbs cap. Check your cap before ordering a replacement since you may have a 16lbs cap already.