I just bought a 2001 XLT with the 4.0. It has just under 80K miles and the previous over did regular il changed with the recommended 5W30 oil. I am considering to help with future timing chain issues etc to swap to full synthetic 5W30. What possible problems might I have by swapping over or is it perfectly ok?

Thanks in advance

 

Should be fine to just switch over.

One thought on expensive oil or "lifetime" coolant for that matter.
Older vehicles will leak stuff, and if it already has any oil leaks, synthetic will leak more, it is thinner.

Regular engine oil has been somewhat modified to work better in engines, but it is still a crude oil product.
Synthetic engine oil was made from scratch FOR use in engines so is "tailor made" for that use, and has benefits.

No doubt in my mind that synthetic oils made for a specific purpose will do a better job than a crude oil product, but................

The crude oil product does work fine.

The timing chain issue with the 4.0l SOHC was a design and materials used flaw, not an oil issue, synthetic for sure won't hurt but I don't think it would help either, it wasn't a wear issue.

 

See this video.
I think it's a waste of money.
Change your oil on a regular basis _ that's key.

In the video the guy talks about an older engine become leaky and noisy.
This is so because the oil molecules in the synthetic oil are all the same size and smaller, where as regular oil are different sizes.
The bigger sizes fill the bigger spaces in an old engine keeping it quieter and less leaky.

There was a traveling salesman that had over a million miles on his Chrysler land yacht with the untouched bottom end _ ran like a watch with regular oil and all he did was change the oil and keep the bottom end clean. This was a long time ago when there was no synthetic oil.