Is there any fast way to be a Mechanical Engineer then doing 4 years?

Generally not. It will likely take 4 - 5 years to complete depending upon the university you are attending.

There are options, but they are not as good as getting the 4 year engineering degree from an accredited university. You can get a 2 year associates degree. This does not offer you the same opportunities as a 4 year degree. You can also go to summer school. This will let you get complete in 3 years. However, if you can coop or do summer internship, this gains you valuable experience.

The basic answer is that if you have 4 year degree from an accredit school, even better, a well recognized school, you will get better opportunities in the short run and the long run. Even with a lot of years of experience, I still get comments on where I went to school. As a hiring manager, I put a 4 years degree as a minimum to review a resume. It is a rare occasion that HR provides me a resume that they think I should look at that does not meet my minimum requirements.

The best advice I have is to figure out how to get that 4 year degree. 2 year associates degree and find a job that you let you work in the field while you finish you 4 years degree may be a way to balance.

It is depends on how far you want to push yourself. I did a two year masters degree in one. It was not easy, but I did it.

Before making your mind, try to plan your degree, courses you are going to take, before hand. Again, I did that!