3.7 engine / year to year

driveability · Jul 31, 2008

I have an 02 with a damaged engine. Most of the 02 engines (used) have high mileage, but I see lots of 04, 05 engines with low mileage but am told there are differences in the engines. What are they? Can I install an 04/05 in my 02 ?

tjkj2002 · Jul 31, 2008

driveability said:
I have an 02 with a damaged engine. Most of the 02 engines (used) have high mileage, but I see lots of 04, 05 engines with low mileage but am told there are differences in the engines. What are they? Can I install an 04/05 in my 02 ?

They are the same from year to year.The only differences are in '03 they changed the coupler on the ehaust manifolds and in '07 they went to a drive by wire TB.

driveability · Jul 31, 2008

tjkj2002 said:
They are the same from year to year.The only differences are in '03 they changed the coupler on the ehaust manifolds and in '07 they went to a drive by wire TB.

I'm not taking your advise lightly and do have years of experience working on modern engines so please don't take me asking for more opinions and information as a insult....

I was told by an EBAY seller the intake manifolds and electrical systems were different.
I have a computer controls back-round, did tune-up and driveability work for years on G.M. systems at the dealership level..

So the manifold coupler, the intake, the electrical systems, and that may be something huge or just rewiring some connectors etc..

Could I get some more input ??
Thanks John

moparman · Jul 31, 2008

Not the same thing but a Daimler Chrysler product - Dodge/Plymouth Neons 2.0 SOHC engines are not interchangable from 00-02 to 03-05 due to a new style computer in 03. The crank sensor was completely re-arranged and the other engine sensors communicate differently.

tjkj2002 · Jul 31, 2008

driveability said:
I'm not taking your advise lightly and do have years of experience working on modern engines so please don't take me asking for more opinions and information as a insult....

I was told by an EBAY seller the intake manifolds and electrical systems were different.
I have a computer controls back-round, did tune-up and driveability work for years on G.M. systems at the dealership level..

So the manifold coupler, the intake, the electrical systems, and that may be something huge or just rewiring some connectors etc..

Could I get some more input ??
Thanks John

hah.gifhah.gifhah.gifTaking anything that a ebay seller is saying as anywhere close to being true is your first mistake.

'02-'04 3.7's are identical EXCEPT for the exhuast manifolds,that is only for the maniflod coupler's where they attach to the rest of the ehaust.It's not 100% forsure that the '05-'07 3.7's are identical due to a different manufacturer for the engine,but the last '05 KJ I worked on had the exact same intake manifold on it as my '02 did,part #'s matched.They did change some of the electronic communications in '05 so of the sensors may be different but they are in the same location.

But why buy a used engine anyway? You can get a new short block,no core charge,for cheaper then 90% of the used engines on the market anyway and then you'll be getting a brand new bottom end.

Mangate · Jul 31, 2008

My 02, and a friends 05, have different intakes, but it may just be the plastic box on top of the maniifold which is absent on the 05, rather than the manifold itself.
Also I have noticed that parts sellers list the fan belt as different for 02-03 to 03-05, don't know what this is about.

driveability · Jul 31, 2008

tjkj2002 said:
hah.gifhah.gifhah.gifTaking anything that a ebay seller is saying as anywhere close to being true is your first mistake.

'02-'04 3.7's are identical EXCEPT for the exhuast manifolds,that is only for the maniflod coupler's where they attach to the rest of the ehaust.It's not 100% forsure that the '05-'07 3.7's are identical due to a different manufacturer for the engine,but the last '05 KJ I worked on had the exact same intake manifold on it as my '02 did,part #'s matched.They did change some of the electronic communications in '05 so of the sensors may be different but they are in the same location.

But why buy a used engine anyway? You can get a new short block,no core charge,for cheaper then 90% of the used engines on the market anyway and then you'll be getting a brand new bottom end.

I have seen a number of 04 engines for less than $1500, the only rebuilt ones are almost twice that//
What is the cost of a long block, block and heads ???

indieaz · Aug 2, 2008

^ Find a used engine and a PCM from the same year and swap both?

JeepJeepster · Aug 3, 2008

They do have different PCM's given the different trannys. Intakes along with the exhaust are different as others have said.

htownwood · Nov 1, 2023

I have an 02 liberty. The motors changed after 04. The camshaft gear is different and so is the reluctor ring. You can buy a newer model engine but those parts and along with the sensors will need to swapped over from the old engine

htownwood · Nov 1, 2023

Oh and possibly the flex plate also. The seller a kit that converts the engine but I'm not sure on how much it costs

htownwood · Nov 1, 2023

The problem I'm having now is I bought an 06 engine for parts and now I'm just realizing that the connecting rods are different. The set from my 02 have the groves on the inside of the rods and the set from the 06 are completely smooth. Would that make a difference when I'm installing the rod bearings?

Kinneygregory4 · Aug 21, 2024

driveability said:
I'm not taking your advise lightly and do have years of experience working on modern engines so please don't take me asking for more opinions and information as a insult....

I was told by an EBAY seller the intake manifolds and electrical systems were different.
I have a computer controls back-round, did tune-up and driveability work for years on G.M. systems at the dealership level..

So the manifold coupler, the intake, the electrical systems, and that may be something huge or just rewiring some connectors etc..

Could I get some more input ??
Thanks John

3.7 engine / year to year

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