I know this is an old thread but which hose do we tap into again for the aftermarket adapter? I see it says upper radiator hose but the ID of my upper radiator hose does not measure 30mm. More like 25mm so the 30mm adapter I bought to do this job does not work its waaay to big. Any idea here??

 

Any big difference between the wireless vs wired UltraGauge other than price?