Is it worth doing a self funded MPhil in Mechanical Engineering, from UK? I have an MTech in Mechanical Engineering from one of the good schools in India. I have been working in industry for the last 6 years in Finite Element Analysis. I have an offer for MPhil from the University of Newcastle, UK. However, this is totally self-funded. I would like to do a PhD, however funding options seem to be really limited.

Is self-funding a worthwhile route to consider? How valuable is an MPhil in industry?
From what I understand, UK MPhils are 1 year research based degrees, equivalent to or slightly above a masters. I am not that familiar with Indian degrees, but I am guessing an MTech is a masters level degree. You say that it is from a good Indian university, so I am pretty sure that if you have some research experience from your previous graduate studies, coupled with your work experience, that you can land a funded PhD position elsewhere. I think doing an MPhil (unfunded) at this time would be somewhat of a sideways step and a costly one at that. 

I am aware funded PhD degrees for international students are pretty scarce in the UK. Most students I know who completed their PhD studies there did so with their own external funding (governmental, third party, etc.). I would suggest targeting other places (continental Europe, North America etc.) 

Also from what I recall, an MPhil is seen as a stepping stone between an MSc and a PhD, so I am not sure how much meaning it has on its own. In general I think an MPhil is earned on the way to a PhD or awarded to students who for some reason are unable to complete the PhD.