Francois,

The oil light on the 81 van's dash will be for oil pressure, not
temperature. It gets it's signal from the oil pressure switch located
next to the distributor. The light may come on momentarily when the
engine is hot and idling, however, because hot oil is thinner in
viscosity. But the '81 has no oil temperature indicator.

The VW Type 4 engine is notorious for dropping exhaust valve seats at
either high mileage or when severely overheated. However, normal
operation should not cause the engine to get that hot if it's operating
within its design parameters. A lean condition in one cylinder can cause
this, however.

You can install a cylinder head temp sensor and gauge that will show you
at what temperature your cylinder head is operating. However, as the
sender attaches at the spark plug and the engine has two heads on
opposite sides of the engine, the setup works for only one head. So you
either need two senders/two gauges or else you will have to assume that
the reading is representative for both heads.

You can also install an oil temp sender and gauge. The sender will go on
the bottom of the engine (there is a replacement plate with sender for
the blank factory plate), and this will give you a general idea of your
whole engine's temperature. The cylinder head temp gauge only measures a
localized area, although it is the hottest part of the engine.

Both gauges and senders are available through VDO, and are not terribly
expensive. You will need to route your own wiring from the engine to the
instrument panel, however.

If your van is in fact overheating, you should find out why this is. It
may not be running correctly if it's getting hot enough to drop a valve
seat. I guess I would recommend both the temp gauge(s) as preventative
measures as well as a general tune up to ensure you are running within
design parameters.

Dan

Fran�ois V�zina wrote:

> Hi all
>
> Last week I lost compression on one piston on my air cooled van
> because of a valve seat that dropped. From what I've seen on the
> type2 list, it is apparently common when the engine is overheating.
> Well I thought those engines were not overheating that much... Some
> fellows suggested that I have installed an oil temperature gauge. I
> remember that some peoples were talking about oil temp gauge on the
> vanagon list not so long ago SO this is my questions.
>
> Does the oil light in the instrument panel indicate low oil or too
> hot oil? (I know it is silly but I don't know)
> If its the latter it did not work last week...
>
> IF I should put an oil gauge is there a particular type to choose or
> the one at say Canadian Tire is OK?
>
> How long would it take to a mechanic to install it ($$$???) (I'm not
> really good in mechanic).
>
> I'm gonna go in Alberta with the family in two weeks (from Vancouver)
> so I don't want to bust another valve because my van is loaded and
> overheat in the rockies...
>
> Any suggestions?? comments??? experiences??
>
> Thank's it is appreciated
>
> Fran�ois
> Fran�ois V�zina M.Sc.
>
> Department of Biological Sciences
> Simon Fraser University
> 8888 University Drive
> Burnaby BC.
> V5A 1S6
>
> Voice: (604) 291-5422
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