Auto Meter Coolant Temp. Gauge

[EL Prieto]

I'm replacing the old VDO gauges for Auto Meter gauges, found the thread sizes in the new coolant gauge is to big for the threads in the block . I'm installing it next to the thermostat, left side. Any body know what size fitting I need to finish the installation ? What thread size in the block and the gauge ? Thanks.

 

[karolko]

those should be 3/8" npt ports on the front face of the intke by the thermostat