K75 Temp Light Always On

[daveson]

Bonus, good work.

Let us know about the results of your oil temperature research. I can't see how the oil temperature gauge reaches the oil from the oil filler cap.

[Laitch]

I can't see how the oil temperature gauge reaches the oil from the oil filler cap.

It probably works like this.

[daveson]

The oil filler cap is about seven inches above the oil level and it's offset to the side of the sump. There are a lot of obstacles in the way. That short dipstick could only measure the air, not the oil. I have a temperature gauge that replaces a coolant cap, I was wondering if that was what was meant, but I don't think so to that either.

[Laitch]

From Wunderlich America, a vendor of this object:

High quality JMP oil temperature direct meter / analogue display; the original oil filler plug must be replaced with the direct blade.

NOTE:

    Please carefully compare the thread diameter, pitch and length of the oil dipstick with the replacement part
    Please note that the probe is often only wetted with spun oil
    A measurement on, for example, the oil drain plug therefore gives a different value

ATTENTION: The air bubble in the sight glass secures the expansion of the damping oil when heated, it is intentional.

[daveson]

Ok, it would be interesting to find out what it reads the temperature at.

I think they might be overthinking it a bit with the damping comment, the filter alone would probably do more damping than the tiny sight glass. On my brick when the engine is running, the oil is below the sight glass. After the engine stops the oil level gradually comes into view, so no damping is required then. I've always thought the only reason for the silver backing plate is to make it easier to see the level. If not for the silver backing plate, if you looked through the sight glass, it would all be black. The holes in the plate allow the oil level to be the same on both sides of the plate. The holes at the top of the plate connect the air on both sides, so it's not a bubble. That's just what I've thought.

[Laitch]

I think they might be overthinking it a bit with the damping comment, the filter alone would probably do more damping than the tiny sight glass.

I believe by "damping" is meant "lessens engine vibrations of the needle," a condition for which the filter would have little effect. In other words, the air bubble stabilizes the gauge's needle movement within the sight glass.

[daveson]

Doh, now it makes sense, when I read sight glass, I was thinking about the one on the brick, not the gauge.