Was having the hardest time finding a replacement thermostat for my 2006 Forenza, and refused to go to the dealer and pay $116 for thermostat, which is prone to failure anyway. Kept getting a P0128 Check Engine Code all last winter and the car ran too cold often and I had very little cabin heat on certain days. Knew I needed to replace the thermostat, but didn't want to put the same factory garbage back in the car.

This ought to help fellow Forenza & Reno owners. I actually have high-quality thermostats in stock, mfg'd by an OE & aftermarket mfg. (made in Germany). These are much higher quality than the GM/Suzuki ones, which are prone to sticking open. It is a complete thermostat/housing/& gasket assy. Dealer cost for parts alone is $116.91. These are available for only $30.95/set. See: eBay item #11044976686
Suzuki Forenza & Reno Thermostat, Housing & Gasket:eBay Motors (item 110449766986 end time Nov-23-09 20:16:26 PST)

FYI - there is also a 180deg. thermostat version available (much more difficult to obtain). I know some people were looking for a colder version than factory spec. These are only $45. Hope this helps save a trip to the dealer and saves everyone some $ & frustration.

Unfortunately, you can't just replace the thermostat internals / mechanism. Comes complete and installed in a new aluminum housing.

I also have really nice polished stainless steel flanged hex bolts to replace the factory reverse-torx bolts - won't have to use special tools to remove again, and these won't ever rust or freeze inside the engine block.

Ken