I found a 2002 jetta 2.0 automatic for sale witha bad engine, then i found a motor for the same year but its a 1.9 deisel and its a manual transmission?
With some twekking is it possible for it to work?
a lot of work but it is possible. you need to swap the harness,ecu, axles, possibly mounts, shifter assembly if yours now is an automatic, theres a laundry list of things, those are a few i thought of quick.
You need a hell of a lot more than a 1.8t long block and it wont be worth it in short.
Most people who think about 1.8t swaps in 2.0s want a faster car and already have a beautifully preserved and modified 2.0, not starting with scrap. Better option is usually to turbo the 2.0
The transmission part isn't a big deal. The cranks are the same except the extra throw for stroke.
If you go 1.8 turbo then that motor will eat that transmission pretty quickly though.
You need the entire harness and everything on the motor for sure, also ECU. Immobilizer delete with ecu change. I imagine the engine mount is the same but don't quote me on it.
Not to mention all kinds of intake and exhaust piping
What is wrong with the engine, that is likely easier than the swap. If you are on a budget swap you'd be best off waiting for a 2.0.
A concerning bit is how did they ruin a 2.0 motor. likely from over heating it, not replacing timing belts or oil starvation. You probably don't want that car as it's likely never had an atf or brake fluid change and would require thousands to become road worthy.
I would just get a clean perfectly running mk3 if you're on a budget, by your post I assume you didn't buy anything yet.
It's all possible but why. You won't have any idea what all is wrong with the parts until it's too late unless you've had experience them both while they were running.
Not sure why I waste so much time explaining hypotheticals.