Soo..basically...you literally "Froze your nuts off"..
All kidding aside..they should be M8X1...some are M8X1.5 Instead of using plain nuts...I use metric size threaded rod couplers...they are longer and give more thread area for the stud to grip onto..meaning less chance of stripping the nut. Also since they are 2-3 times longer than a nut...they are easier to put on due to the cramped quarters under the engine....and keep water and road residue off the threads so they do not corrode. Just my 2 cents....
