Vanagon Type IV air-cooled engines use the same single wire sensor.
It's possibly to get corrosion and pore conduivity where it screws in to
the head.

'as always' ..VW upgraded it in the next engine..the 1.9 WBXR ....with
two wires to the ECT sensor ..one a dedicated ground.

pretty sure it tells more that just 'engine is warmed up' ..it tells the
ECU the temp of the engine, one input it uses to decide how long to hold
the injectors open, in milliseconds.

premium is not really recommended in my world....exotics yes ..VW's no..
mid-grade is fine.

On 2/6/2014 5:55 PM, Stuart MacMillan wrote:
> My '78 van had a #3 cylinder head temp sensor in the casting as part of the FI system.  I think it was there just to tell the ECU when the engine was up to temp, and it was often the cause of drivability problems.  Did they remove it when they put that engine in the early Vanagon?
>
> Sometimes you can have more information than you can deal with effectively, and it just causes stress.  Maybe it's enough to be sure your engine is in tune, run premium gas to (hopefully) avoid detonation at hot temps and forget about it.
>
> Stuart
> Way too many VW vans in my past
>
> On 2/6/14, Glen Moon <glenmoonfl@hotmail.com> wrote:
>
>> Rebuilt 2.0 air cooled.  Having mechanic put a Dokata cylinder head sensor
>> under #3 plug,  to gauge on dash.   What should the temperture be?