ok so my thermostat neck on my s5 motor is cracking and breaking. i have a broken bolt on one side. i have a s4 water pump cover and thermostat neck in the garage... can i put it on the s5 block with no problems? will it match up ok? its a non turbo s5 motor.

 

no

one has 8 bolt water pump and a three bolt thermo neck with a FD style thermostat and a rubber outside ring gasket,,, and also has a crazy suction leg pipe angle to clear an OMP
( s5 )

the other has a 7 bolt water pump ( that cant swap tho s5 ) , a 2 bolt alum thermoneck ( with filler cap )
and the old 12a style thermostat

 

i dont know about clearance of the OMP...but you can use the s4 on an s5 block but you need the s4 gaskets, s4 waterpump, s4 thermostat and s4 thermostat housing. if you are talking about a NA motor, then i have no idea.

 

You can get an aftermarket aluminum one here:

http://www.mazdatrix.com/b8.htm