Hi everyone,
I have been contemplating the issue of guessing at the coolant temperature for a while and I too want to install a gauge to get a more accurate reading on this.

I have the regular VDO sender that fits on the the big hose going from the water pump to the thermostat.  It is threaded, I believe at 8x1.00 which is unusual for all other VW threads (usually 8x1.25 but that OK) ( This is the common thread on an Alfa Romeo....SO!)

The three locations that I was thinking about are the following:

1) the top air plug on the radiator is the same size 8x1.00 and it fits perfectly, trouble is that you are only getting relative temperature since you are far from the engine. It may also not be accurate if you have an air pocket in the coolant circuit.
This works and it is quick to install.

2) get a different sender from a BMW or other VW that will fit in the cylinder head drains plugs. Simply remove the allen bolt (if you can) and install the new sender.
Does anyone know the diameter and thread size of the the cylinder head drain bolts?
I know that Fast German Auto in Santa Ana Ca makes some gallactic probe to insert in the hole to keep the ions from crystillizing on your polished head. (oops did I say that?)
This would be the most accurate temp reading.

3) tap the 8x1.00 (or whatever it stinking is) into the flat spot on the plastic T section. I think that all vans have some T section to connect to the radiator hoses.  This would also be easy to do and you would get a close reading on the engine temp.

My three cents.
Joel
89 Syncro Westy
Rochester NY

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