I bought a new (aftermarket) CTS for my '92 3VZE Pickup, and can't find any socket that will fit it. 19mm is really close but is just a bit too small, and 21mm is too big. 3/4" is close but again just a bit too small, and 13/16" is too big.

I figure I'd size the new one up with the right socket before I try and fit one behind the intake plenum and squeeze my hand back there while laying across the engine, so I haven't sized the stock one on the engine yet, but assumed the new (aftermarket) one would be the same size.

Is this just aftermarket crap or is this thing known to be an odd ball size?

Thanks.

 

Is it possible that it's 20mm for some strange reason, just assuming it's metric.

 

sand it down a mil

 

It's not 20mm either, 20mm is just a slight hair too big. I tried a 12 point 20mm socket and it seemed like it would strip it.

So nobody has ever changed a coolant temp sensor in a 3VZE and can tell me what size socket it is??