[T3] Engine oil temp?

[Jim Adney]

On 19 Jul 2020 at 9:42, Mike Fisher wrote:

> Jim told us that oil pressure isn't important.  It's the oil flow?

Yes, it's the flow, not the pressure, that's important. Unfortunately, flow is 
actually quite hard to measure reliably. I've been down that rabbit hole with 
large, water cooled electrical power supplies that have to run 24/7/365. Most 
such sensors tend to get stuck after a few months, so they don't trip when 
the water supply fails. The result is $$$$ down the drain.  

So pressure substitutes for flow. This works because the VW engineers 
could predict the amount of pressure drop that sufficient flow would produce 
with the weight of oil they specified.  

Two things to keep in mind:

The bearings need less flow at idle than at medium or full power.

Moving to thicker oil will increase the pressure, but may not increase the 
flow. In some circumstances it may actually reduce the flow.

Being able to see problems before they become PROBLEMS is nice, but 
keep in mind that millions of cars out there, not just old VWs, get by with just 
an idiot light.

Years ago I installed an ammeter and mechanical oil pressure gauge on my 
'68 Square. That was interesting, but I gave it up when the plastic line leaked 
where I had kinked it, next to the battery. The resulting oil spill probably kept 
that side of the pan from rusting out a bit longer, but I did away with the 
gauges after that.

A friend did the same thing with his Beetle, but used copper tubing. That 
never leaked, but it eventually managed to short out against the large 12 V 
terminal on the starter. I think the short burned a hole in the tubing, so that 
was removed.

So my experience was that it seemed cool to be able to monitor these things, 
but it never gave me any advantage and ended up with significant 
disadvantage. As a consequesnce, my recommendation has been to save 
that extra attention for the road ahead and the other drivers around you.

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