The thermostat on my 1996 960 busted into 3 pieces, my car has also been surging at idle sometimes up to 3000 rpm's and then running rough, would the thermostat cause the idle to surge? Also, do I need to get a Volvo branded thermostat or will aftermarket brand work, the closest dealer is an hour away that's why I ask.

thanks in advance!

 

Aftermarket will work fine.
Yes it will mess with the idle as well.