I have a 2003 mercury mountaineer and it has been diagnosed by a mechanic as the timing chain jumped or snappped and will no longer run. He says to get a junkyard motor for it instead of fixing it. I found a 2002 ford explorer motor with 121k miles on it for 500, but the thing is mine is a flex fuel and this motor is not. can I just drop this motor in or does it need a flex fuel?

 

Which motor do you have, the 5.0 V8 or 4.0 SOHC?

I'm not sure if there are internal changes in the Flex Fuel engines, or if it is confined to the ECM and other electronics and intake hardware.

A used 4.0 SOHC should have the tensioners and guides replaced, especially 2003 or older, or anything with more than 10 miles on it.

They sure charge more for a used Flex Fuel. Even these engines should have the tensioners and guides replaced:

http://www.lowmileageparts.com/default.aspx

 

it is the 4.0 SOHC

 

WAG: Install that 2002 motor with all your exhaust, intake, sensors, electronics etc and run it on gas only.

BUT replace the tensioners and guides FIRST. That must be done with the engine out.

Never R&R one of these without doing that. Here's why:

https://www.ford-trucks.com/forums/1...ease-help.html