[T3] Oi Pressure Sensors

[Jim Adney]

On 1 Feb 2011 at 11:40, J. Jonik wrote:

> I have four oil pressure sensors.   One is in the car, but it leaks.
> Two leak...not much but still messy.
> Two don't work the dashboard light.

> Is there any trick to stop leaking?  Some heat and pressure maybe?
> What's inside those things? How do they work? 

The pressure pushes up on a spring loaded diaphram that has a rivet 
in its center, breaking contact between the base and the rivet. Over 
time the rubber seals shrink, making the crimped seal around the edge 
ineffective. I know of no way to fix this. They are cheap and they 
are easy to replace. That's what I do.

Ones that are not in use sometimes get corrosion on the contacts 
inside and stay permanently open. It's somewhat sad, but if you 
pressure cycle them several times and they don't fix themselves, 
you'll just have to replace them.

> As for the light...using OHM meter, found no continuity between
> screw-in end and the electrical tab on top of 2 sensor.     The one
> that works for the light does have continuity.  (I didn't take the one
> out of the car. It's light works.) 

That sounds like it would produce your symptoms exactly. The one that 
shows continuity with no pressure is good, as long as it doesn't 
leak. If it leaks or shows no continuity, toss it.  


-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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