Solved Engine Swap 3.5 to PI 3.7 successfully

[ViroSpaz]

If I am following this correctly I can change my 2016 3.5 eco-boost to a 3.7 without any changes or computer updates?

 

[peterk9]

If I am following this correctly I can change my 2016 3.5 eco-boost to a 3.7 without any changes or computer updates?

Just wanted to say, Welcome to the Forum.
Are you sure you have the ecoboost and not the 3.5L V6? I don't think the XLT had a 3.5L ecoboost.

Peter

 

[ViroSpaz]

Just wanted to say, Welcome to the Forum.
Are you sure you have the ecoboost and not the 3.5L V6? I don't think the XLT had a 3.5L ecoboost.

Peter

It might actually be just flex fuel.

 

[peterk9]

It might actually be just flex fuel.

I think if it flex-fuel capable it should show on the gas door and perhaps on the liftgate.

Peter

 

[FordMeansFixOrRepairDaily]

Just wanted to contribute to the information in this thread. I only made an account to post this one time and likely will not reply. Finished up the swap in my explorer and used some resources in this thread but wanted to add some things from my swap. I am not a Ford expert. I'm mostly a diesel mechanic.

My scenario: 2014 Explorer XLT 4WD/AWD 3.5NA 215k miles with a hole in the block from when I took out the oil pressure sensor. The issue was the oil pressure light would trigger and it was also leaking oil from the sensor area. Went to take the sensor out and the engine block came with it.

I swapped in a 3.7NA motor and transmission assembly from a 2017 Ford Police Explorer with 60k miles. I purchased a wrecked but running police explorer surplus for the same price people near me wanted for a questionable mileage "running" motor. Parted out the rest of the explorer and on paper I technically turned a profit.

Some tips/specifics:
You do not need to pull the hood. You can strap it back. The motor is pretty easy to remove. You lift it straight up then front out of the engine bay. I removed all front end components including radiator and condenser.

No tuning of ECM required. Take the original harness (2014 motor) and put it on the new (2017) motor. Swap 2 upper cam sensors off the old motor. You have to reuse all your old motor coil packs. Keep the catalytic converters on but swap the o2 sensors from the old motor to new motor. You will figure out quickly what parts you need to swap off the original motor when you try to connect the harness up on the new motor. Do this with the motors out of the vehicle.

Use the lower transmission/engine mount off the old motor on new motor.

Do not cut any hoses. The new motor has a water pump coolant hose that has an extra T off it. Someone in this thread recommended capping it. I reused the original 3.5 motor coolant hose and did not have to cap.

Reuse the original 3.5 transmission cooler adapter block.

The 2017 3.7 PIU had a supplemental transfer case cooler. This is not necessary for civilian regular use and did not even come on the original 3.5. Cut the 2 hoses and put in a tube to bypass the cooler then secure it somewhere. The transfer case will have a electrical connection on it that will not connect to the old harness and is not needed. I'm pretty sure it is for putting in "low" gear in the police interceptors (used for pushing disabled vehicles ar low speed).

I did not have to do any modification to the exhaust and my old exhaust pipe bolted up. Reading different forums it looks like exhaust may be a concern for older (2011) explorer models.

With the battery disconnected, short the positive and negative battery cable to reset the throttle body settings.

I've put approximately 500 miles now on the new motor swap. Definitely a horsepower increase and all my modes and sensors work the same.

 

[vmozer]

This seems, quite promising. However, I have some doubts about not having to reprogram the ECU/PCM. If using the sensors etc from the 3.5 makes the PCM think it runs the 3.5 wouldnt it run lean when there is a larger displacement? Also, did anyone try emissions test or dyno the car after such an update?

 

[14explorerxlt]

Hi, I wanted to provide some insight if need to replace your engine. I successfully swapped my 2011 explorer 3.5 NA with a 3.7NA from a 2016 PIU Explorer. After lengthy research of the 3.7 the only difference is the bore size, to give it more power. The ECU, injectors, coilpacks, fuel rails and intake is the same as a 3.5. Therefore, it was a direct swap with very minimal change. The changes would be the same if you swapped a 2011 3.5 NA with a later year 3.5 NA.

Use your existing motor harness
The ECU doesn't have to be changed or re-tuned
You do not have to change injectors or coil packs
You CANNOT use a 3.7 from a F150, Mustang or Transit van (the blocks are different)
You CAN pull the engine from the top of the engine bay.
If you use your earlier year exhaust manifolds, you have to move the studs to match the correct pattern.
You have to swap 2 cam sensors if you have older 3.5, to fit your motor harness
You have to cap off the under intake coolant line ( later year 3.5 and 3.7's have this)

Hope this helps if you need replace an engine and are looking for a little bit more power.

I also wonder now if all modifications for a 3.7NA (f150s and Mustangs) will directly work with 3.5 NA's explorer (ie superchargers, tuners, etc)

I swapped my 2014 explorer XLT 3.5 for 2017 XLT 3.7 liter engine new PTU and no issues has great power. Hope this helps just change all manifold gaskets, remember the oil filter on 3.5 is smaller than 3.7 but will screw on but use 3.7 oil filter more oil.

 

[peterk9]

I swapped my 2014 explorer XLT 3.5 for 2017 XLT 3.7 liter engine new PTU and no issues has great power. Hope this helps just change all manifold gaskets, remember the oil filter on 3.5 is smaller than 3.7 but will screw on but use 3.7 oil filter more oil.

Welcome to the Forum.

Peter