2003 4.0 -Replacing Flex Fuel engine with non-Flex | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

2003 4.0 -Replacing Flex Fuel engine with non-Flex

T-Bone75

New Member
Joined
March 25, 2015
Messages
3
Reaction score
0
City, State
Iowa
Year, Model & Trim Level
2003 Mercury Mountaineer
Hello everyone,
I recently acquired a 2003 Mountaineer with a trashed 4.0L VIN K Flex Fuel engine. I came across a 2002 non-Flex 4.0L out of an Explorer for a good price. What do I need to do to put the non-Flex engine into the Flex vehicle? What parts should I use off the original engine? Injectors, throttle body, intake? Or, will it work as it is. Thanks in advance for any replies.
 






I'd think you'd be fine as long as you never ran E85. But the next owner may be in trouble.

I'd use the block, heads, intake, pan etc... But use ALL of your sensors and switches.

My opinions, not based on facts.
 






All you will need is the flex fuel engines injectors, fuel rail, and upper intake assembly. You will probably want to replace the upper intake bolts because they use "isolator" gaskets and will most likely leak once removed and reinstalled. They run about $80 a set unless you get them on ebay. Just look up "intake isolator bolt set" Fords 3.8, 4.0, and 4.2 use them, possibly more engines as well, but not hard to find cheap on ebay if youre willing to wait on shipping. Very easy swap.

Edit--- For later searches/future info -- Any Ford 4.0 SOHC engine will interchange either way with those changes. Do check your sensors, but 90% of them are the same reguardless of flex or non flex, ranger, mustang, explorer,mountaineer, etc.
 






Back
Top