Re: Rusted open/closed heat riser valve

Posted by Owen_Dyneto On 2010/2/11 13:46:19

Yeah, unless you're in an exceptionally cold climate your car can function satisfactorily with the valve removed or permanently open. If the counterweight is still on the other end of the shaft, it's open when the counterweight is down. The bimetallic spring holds the valve closed when cold and as it heats if releases part of it's tension by unwinding and allows the counterweight to overcome the force of the spring. Of course the shaft must move freely for this to occur. Some folks have removed the exhaust manifold and drilled it to accomodate stainless bushings for the shaft - usually not necessary but elegant.