My 2007 JK's 3.8L engine is starting to get tired. I currently have +200K on it and it's starting to lose power and run rough. I am considering a few options like rebuild it, swap in an engine, etc... One of the options I am looking at is getting a low mileage Chrysler 3.8L engine out of a salvage yard to swap in then selling the JK for a newer model (like a JL). I noticed that a JK 3.8L salvage engine is ~$2,500 but a 2008 to 2010 3.8L from a Caravan is below $1,000. I know the JK 3.8L is based off the same engine as the Caravan, however, I don't know all the differences. Any one know the differences? Can I drop a 3.8L Caravan 3.8 L into my JK (with minimal exchange of parts)? Any one do this before?

Thanks

 

There was a thread on here and I guy did just that, I can't seem to find it at the moment but he also did a YouTube series on it too

 

Saw the Videos and write ups. He (Ametzker) used an older Caravan engine (2004) which has enough differences (like motor mounts and such) that it did not work. Some made the comment "FYI in 2007 Chrysler started using the same block casting number for the minivan and the JK Wrangler." at the end of the thread. Makes me think that if you use a newer Caravan engine, you can could at least use the majority of it (like the block and heads).

 

I pinged a Salvage yard who had a few newer 3.8 L Caravan engines on eBay, as well as, JK engines (for +$1000 more) to see if they had any answers regarding the differences between the two engines. Alex B from A & A Auto and Truck LLC in Orlando, FL made the statement "A Caravan or Pacifica will 100% not work in your Wrangler. From what I understand there are differences in-side the engine that will send the wrong reading to the ECM and the engine will not run." When asked if he had more information on what the "in-side differences" are, he replied "The Wrangler engine is different. Sorry, you don't get that." Not a useful answer.

Any folks on this forum know the differences between a Caravan 3.8 L engine and a JK 3.8 L engine? Also, I noticed that a +2008 JK 3.8 L engine is not compatible with a 2007 JK. Anyone know the difference between a +2008 JK 3.8L and a 2007 JK 3.8L?

 

Jsears (member here) did an 11 motor in his 07 and had to make changes to the cats. It was frustrating for him at the time but I think it worked out for him just fine in the end.

 

I'm guessing here, but I'd bet the camshaft has different timing/duration between the Caravan and the JK. The idea being that the JK needs more low-end torque. A different camshaft would change the volumetric efficiency tables in the PCM (which can be changed with tuning software).

Edit: Just lost that bet... Looked it up and camshafts are the same between 3.8L Caravan & Wrangler.

 

See the attached PDF on the 3.8L engine. Lots of info on the differences between models throughout the years.