What does this sensor on Toyota thermostat housing do?

It screws into the thermostat housing on my 89' Cressida. I see it
id'd as bi-metallic vacuum switch - has an AISIN p/n 90925-05068

Link to pics below. The hose nipples have deteriorated and broken.
What does it do and what happens when it's not working? Car seems to
run okay but obviously it's there for a reason.

Thanks.

https://encrypted-tbn1.gstatic.com/i...xlRnfg3XQu8wFg

"brassplyer" > wrote in message
...
> It screws into the thermostat housing on my 89' Cressida. I see it
> id'd as bi-metallic vacuum switch - has an AISIN p/n 90925-05068
>
> Link to pics below. The hose nipples have deteriorated and broken.
> What does it do and what happens when it's not working? Car seems to
> run okay but obviously it's there for a reason.
>
> Thanks.
>
> https://encrypted-tbn1.gstatic.com/i...xlRnfg3XQu8wFg

"This device is a heat-sensitive switch that remains closed until the
engine's coolant reaches a certain temperature. The PVS screws
into the intake manifold, thermostat housing or engine so the heat-
sensing element is in contact with the engine's coolant. Inside the
switch is a wax plug that pushes a sliding plunger to uncover or
block vacuum ports in the switch. As the engine heats up, the
wax expands and pushes the plunger up until it uncovers or
blocks the vacuum port. At this point, vacuum to the device that
the switch controls is either applied or blocked. Severe engine
overheating can damage the switch, making replacement necessary."
http://autos.yahoo.com/maintain/repa...ques080_1.html

"brassplyer" wrote

> It screws into the thermostat housing on my 89' Cressida. I see it
> id'd as bi-metallic vacuum switch - has an AISIN p/n 90925-05068
>
> Link to pics below. The hose nipples have deteriorated and broken.
> What does it do and what happens when it's not working? Car seems to
> run okay but obviously it's there for a reason.

According to Autozone's 89-90 Cressida diagram, your BVSV decides when
the charcoal cannister is allowed to vent its vapors into the intake manifold.

http://tinyurl.com/agws2sj
or:
http://repairguide.autozone.com/znet...5280081681.gif

"Sanity Clause" > wrote in message
...
>
> "brassplyer" wrote
>
>> It screws into the thermostat housing on my 89' Cressida. I see it
>> id'd as bi-metallic vacuum switch - has an AISIN p/n 90925-05068
>>
>> Link to pics below. The hose nipples have deteriorated and broken.
>> What does it do and what happens when it's not working? Car seems to
>> run okay but obviously it's there for a reason.
>
> According to Autozone's 89-90 Cressida diagram, your BVSV decides when
> the charcoal cannister is allowed to vent its vapors into the intake
> manifold.
>
> http://tinyurl.com/agws2sj
> or:
> http://repairguide.autozone.com/znet...5280081681.gif
>
>
>

My wife wishes I had one of those. I vent my vapors any time and anywhere
I want.