Aluminum Thermostat Housing Kit A
On 2wd models 86-91 this part was originally made of plastic, while on 4wd models it was made of aluminum. This kit includes all of the parts needed to convert from your 2wd plastic thermostat housing to the aluminum Syncro version - including all of the seals and sensors needed to do the conversion. The difference between the two units is that with the plastic ones there are two sensors that just pushed into the holes and clipped in place while with the aluminum ones there are different sensors that screw in place. The connector for the fuel injection temp sensor will be the same but the other connector needs modification discussed below. This part is an improvement over VW's original plastic unit. The kit includes the thermostat housing (factory VW part), fuel injection temp sensor, gauge temp sensor, one electrical connector, thermostat seal, seal from housing to cylinder head, two bolts and washers to attach housing to cylinder head. Thermostat is not included (this way if you are also needing to replace it, you can choose between the 80 degree or 87 degree option and thermostat housing top is not included so you have the option to reuse yours or purchase one (025.121.114).
Electrical modification - The gauge sensor is a 2 wire plug on the plastic units, but with the aluminum housing, the sensor grounds through the mounting threads and only one of these wires is needed. As such, simply cut the yellow wire with the red stripe close to the connector and install the female connector included and push it onto the gauge sensor that comes with the kit. The other wire is no longer necessary so cut it back where it comes out of the harness and remove that wire and the connector that will now not be required.