I have a 2004 Grand Caravan, about 115,000 miles. For the last couple of winters, sometimes the steering wheel is almost impossible to turn to the left when engine is cold. I can leave the house and turn right, but at the first left it is very hard to turn the wheel, and then it pops and is ok.

 

Welcome to DF
You may want to replace the power steering reservoir and pump. That has been the most common problem.

 

This problem is very random, almost never happens in the warm weather. It only occurs when the van is cold, and turning to the left. You can turn to the right with no problem. When it happens, you have to turn it very hard, and then it will "pop" and be normal.

Is this still tied to the power steering reservoir?

 

Had the same issue with a Buick and it turned out to be the rack was sticking. I used Lucas power steering treatment which didn't fully solve the problem but made it livable for another two years.