Will a 2003 4.2 V6 out of a f-150 fit in a 1997 f-150?


Old 02-08-10, 08:05 AM
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Will a 2003 4.2 V6 out of a f-150 fit in a 1997 f-150?

I have a 1997 F-150 with a 4.2 V6 and a 5 speed std. At 110,000 miles the intake manifold gasket leaked on top of #4 cyl bending the rod and busting the piston.I was told that 1997 and 1998 where bad about doing this. Now i have fond a 4.2 V6 out of a 2003 F-150 and a 5 speed std for $250.00.

Will this fit in my 1997?

If so what will i have to do to make it work?
I have had a lot of Yes and No's.
But if no way not its the same motor?
please help me out if you can.
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Old 02-08-10, 11:23 AM
Join Date: Oct 2008
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I don't know anything about these specific engines, however I have found the following to be true with all vehicles/engines lately...

That is they *always* change things from year to year. So if you have a 1997 whatever vehicle, guaranteed something will be different on a 1998. And then something else different on a 1999.

For example I've seen the same exact wiper switch on two different years where they changed the wire colors, the connector, and went from + activating the wiper to - activating the wiper. (The wiper switches and wiper motors are not interchangeable between the two years even though they look exactly alike.)

Then engines these days include the engine, wiring harness, and the engine computer. This works as a *system*.

Then the engine computer has "software" (firmware) in it to operate all the various sensors. And is programmed for that specific engine. The programming could be different depending on accessories the vehicle has? (They keep this all secret, so no telling!)

One or more engine sensors could be different with a different model year. And the "software" would be changed in that model year computer to work with the different sensor. The sensors might look exactly alike, but would be different "electrically".

Older vehicles had just one engine computer and that was about it. But with newer vehicles, they have added on more and more "other computers". And these other computers (like a computer for an automatic transmission) communicate with and function as a system with the engine computer.

One thing is diagnostics. They can set up the various computers to monitor other computers. And if one computer is not working, then one of the other computers will issue a "check engine" code and turn on the check engine light.

A car I have has the engine computer wired into the air conditioning. Under certain situations like wide open throttle, the engine computer shuts down the air conditioning. The air conditioning also does not directly control the A/C compressor. It sends a signal to the engine computer, then the engine computer turn it on (and also adjusts the idle).

So is that engine the same exact engine?

If not, then you would also need the wiring harness and engine computer for that engine.

Then does that engine computer expect the other computers in the vehicle to be present? Can it operate without those other computers?

Does your current vehicle have any other computers besides the engine computer? If yes, I would bet those would not interface with a later year engine computer.

Then so far as engine sensors go, various model years and the same sensor might look alike, but are they the same electrically? Well that is very difficult to tell because all you get is a part number and no other information when looking up the part!

Basically what you would need to do is get a factory service manual set for your existing vehicle. See how everything works and see if the engine computer is independent of anything else on the vehicle.

Then also get a factory service manual set for the new engine vehicle and see if that engine computer is independent of any other computers on the vehicle.

I suppose you could install your own engine computer? Here is information on one of those...
MegaSquirt - Electronic Fuel Injection Computer by Bowling and Grippo 2010

Here is the "software" for that computer...
Old 02-08-10, 12:23 PM
Join Date: Mar 2009
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I wanted to add that any vehicle's parts can change even within the same model year, so even that is no guarantee that parts from one vehicle of the same year will fit another. During a new vehicle launch for example it wasn't uncommon in the very recent past to see over 3000 engineering changes during the first 3 months of production. I remember situations that were even worse than that. Even during the model life cycle there were still hundreds of changes per year to deal with. Many of these changes created new parts requirements. The Japanese generally get more things right early on prior to production start, but they too have ongoing changes to their products on a week to week basis. In some cases the changes do not affect 'fit, form, or function', but in others they do which then require new parts to be designed and used, and then create new aftermarket/replacement parts requirements which are not always interchangeable with the previous parts. This is why it is often important to provide VIN numbers when ordering non maintenance type parts. These days it is far more complicated than it was even 25 years ago, as all makers are constantly improving their products as issues arise in the field.
Old 02-09-10, 12:59 AM
Join Date: Jul 2009
Location: Washington State
Posts: 312
Must have been a major redesign in 2000 everything I can find lists 99 down on the 4.2 will work in the 97.You probably could make the 03 work in that but it won't be a "bolt in" job you could be looking at everything from the fuel pump and lines to computer and wiring harness not to mention possible drive line issues since your looking at a motor tranny combo even the slave cyl may be different and not mate up with your clutch master.
Good Luck
Old 02-10-10, 07:32 AM
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Thanks to all of the replays.

Now i don't know what to do.

Was figuring i was going to have to use all my sensors,intake manifold and all that.

But did not know that all that was going to have to be dun.

How about tacking all the internal parts out and put them in my block?

I did call my local ford dialer and thy said it was the same block but i was going to have to change all my intake and ex manifold.

But they are in a little town and may not know what thy are talking about.

Maniac Mechanic
I'm only getting the motor my tranny is in good shape.

I do know that a new one from ford is $4500.00 and a rebuilt one is $1700.00 to $1900.00 and a used one is $800.00 to $900.00.

I'm just trying to save some money $250.00 looks good to me.

If some one has don this let me know?

Thanks agen to all the replays.
Old 02-11-10, 02:00 AM
Join Date: Jul 2009
Location: Washington State
Posts: 312
Did some more research and discovered the redesign took place involving mostly the heads so IF your 97 was manufactured after 07/31/97 you can use your upper and lower intake manifolds and pull this off if before that date you will have to use the lower that came with the motor (if it has one) or get a lower manifold and the upper should bolt onto it any sensors may be a problem that are on the lower one however none of them have an interchange,(could be plug ins, locations,sizes,ratings) and may require some fabrication.The exh manifolds don't interchange at all so your looking at the ones with the motor or getting for that year and if the outlet location is different some exh work as well.
Don't get involved in this kind of work too much due to having to charge my cust actual time but have built some interesting things.It boils down to how much you want to DIY and fabricate if ness. or contract out.( Have put a 3.8 motor and Trans out of a Monte Carlo SS in a Corvair Van)
Old 02-11-10, 06:33 AM
hubba's Avatar
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OK Maniac Mechanic.

How do you find what the date of manufactured is?

The engine out of my 97 has the upper and lower intake manifolds.

Where are you getting all your info from?

I have looked on the net but can't find a lot about it.

Thanks for all your help and keep it coming.

It has been down for about 2 years now and i need to get it back going my feet are starting to hurt. lol

Old 02-11-10, 10:41 PM
Join Date: Jul 2009
Location: Washington State
Posts: 312
Can't give all my secrets away LOL! I currently have my own shop in Wash State before that worked in the auto wrecking industry as a sales rep. still have access to Hollender inventory system (used by wrecking yards to cross ref. used auto parts)
and have paid subscriptions to Ford tech line Gm , Chrys And imports with All Data Pro as a back up.But enough of me LOL. The manufacture month and year will be on the vin tag on your driver door if it says anything less than 7/97 you will have to do the swap I mentioned(03's lower intake your upper) if it says 7/97 you will have to run the vin through Ford to get the date 8/97 or later you should get away with the other combo mentioned.(your intake but exh mans from the 03 regardless)

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