I have a 2000 xj 4.0 with 227000 miles. I would like to drop a fresh engine in, but no one seems to have one for me to purchase. Can I use an engine from another year and just stip it down to the long block or does it have to be a 2000 or 2001 due to the changes they made that year (i.e. electronic timing, different intake/exhaust manifold)? Mine still runs very well...good compression, doesn't burn oil, but with that many miles, I don't know how long I feel I can trust it. Thanks J

 

Just for what it is worth, I would dare say that I would be more concerned with sensors, etc rather than the engine itself. If you have done good maintenance and it is not giving any trouble, why fix what is not broken? The 4.0 is one of the most dependable motors made and rarely will one just let you down. The biggest thing that usually fails is the crank position sensor but it will usually give you some warning before it fails. I still drive a 94 cherokee with almost 192k on it and aside from the normal wear, it is a great motor and i believe i would be more concerned with transmission failure than the engine. maintenance goes a long way in preserving the life of any vehicle

 

Thanks for reply. Yes, it is very well maintained and most of the miles are highway miles. It still runs good, but seems to be a little down on power. I'ld like to buy a new engine and keep this one for a rebuild. I've just about replaced every sensor on it, with the exception of the CPS and the engine really doesn't give me any trouble. I agree that the 4.0 is probably the most bulletproof engine ever made (when properly maintained), but 227,000 is alot of miles for any gas engine...

 

Not really My Grandfather got over 600K on a Ford Windsor 351 in a 69 Rideau 500 he bought from my father. It's all about the maintainence.
He was head mechanic at his shop. The car was still going when he sold it. How is the compression? And oil usage? Key indicators of future problems. Just putting on a rebuilt head will freshen up the engine.

 

Maintaining one well is the key. Ive seen the 4.0s with as many as 350K on them and still not giving any trouble at all and being driven every day.
When you are asking about one from another year working, are you wanting to build it, or install it used ?
If you are wanting a already rebuilt motor try here http://www.jasperengines.com/find-installer.php
We havent had any trouble out of their engines or transmissions.