What are the torque specs for upper motor mount bolts 21mm,18mm,15mm on my 2007 ford fusion 2.3L
You don't need to know the manufacturer's specific torque specifications for every bolt in your vehicle. Beyond a few specialty threaded fasteners, you just need to know what size and grade or class you're dealing with. While cylinder head bolts should receive the manufacturer's specific torque application, motor mounts can use a more general approach.
First off, bolts are measured by their body (outside) diameter, not the size of the wrench that turns them. The wrench size is also known as the 'width across the flats'. The body size is also,known as a bolt's 'nominal size'. You don't have 21mm, 18mm & 15mm bolts; you have M14, M12 & M10 bolts.
You also need to know what grade (SAE) or class (metric) of bolt you are using. This is reflection of the bolt's type of carbon steel and/or alloy and directly affects its tensile strength. Bolts that hold on bumpers, trailer hitches, motor mounts, cylinder heads, etc. are typically a lot tougher than a garden variety bolt; hence they have a higher 'grade' or 'class' and are marked appropriately. Higher grade/class matching nuts are marked as well. Don't make the mistake of using a lower grade nut with a high grade bolt.
So if you know the size of bolt you are using and what grade it is, you can apply the figures from the following chart for either the recommended ft/lbs or Newtons of torque to apply. Note that many charts providing recommended torque specification give separate entries for dry and wet. If you are planning to apply Never-Seez or some other commercial lubrication product before assembly, use the correct column for the torque specification.
I cannot make a recommendation because although I believe your bolts to be a 10.9 metric class (the equivalent of SAE grade 8), I have no proof that this is so.
¹ Image courtesy of Rick's Free Auto Repair Advice.
² Image courtesy of The Nut Place.
³ Image courtesy of Atlantic Fasteners.
⁴ Unknown image source.