Green warning oil light

[Milou]

I'm not sure what it means....:

Recently, the green oil light on my 911T Targa 1970 (simplified dial) turns itself on when the car's engine idles.

When the revs are above 2.000 rpm, it turns itself off, but when I slow down and fall below those revs, it comes on again.

It used to light up only for a short period of time when I started the engine, and then turned itself off after that.

Do I have a problem with the oil pressure, or does the sensor needs to be adjusted?

Thanks for your help!

[orange911]

Make sure someone hasn't switched the leads with the "GEN" light. My generator light comes on a idle when just started, but goes away after a few good revs.

Olin

[John Z Goriup]

In cases like that, before you look for electrical gremlins and philosphize whether it's a wire, a connection, a bad sensor,etc., ..........I recommend first putting a calibrated mechanical gauge on the engine to check what the actual pressures are throughout the RPM range and then proceed from those results.

JZG

[Milou]

Thanks Guys for the help, I really appreciate.

I won't take any risks and have the car check by my mechanic.

best,

Thomas

[edmayo]

Milou, when you say "simplified dial" do you mean you have only the oil pressure warning light and NOT the numerical gauge? If so then it does sound like you only need to replace the oil pressure sending switch. If however you are still getting "unusual" responses from the warning light, then by all means do as John suggested and have the system checked with a temporary mechanical gauge hook-up.

[gulf908]

Milou,

A green oil pressure light was not original to the combination gauge until the '74 MY.
Picture,please,to see what you are looking at.

Cheers,
Dennis.

[66S]

The 911 motor has low oil pressure at idle, that is why Porsche put warning light switches on 911s that work at lower pressure than most. My theory is that the cam oil squirter tubes bleed off pressure at idle. Pressure at higher RPMs is what is important.

[Milou]

Thanks Guys,

Here is the dial I'm talking about (sorry for the bad picture). As far as I know the car is fairly original:

[68911+1]

Milou,

A green oil pressure light was not original to the combination gauge until the '74 MY.
Picture,please,to see what you are looking at.

Cheers,
Dennis.

I believe that the early cars had the green oil pressure light as stock, even the 912's and that changed about '69.

Here is a photo of a '68 911 gauge with the green indicator.

[Milou]

I read the owner's manual (! should have done this in the first place...!) and it confirms that the oil light on the simplified gauge version (illustrated above) is green.

It says that if it turns itself on while driving one should stop immediately and check the oil level. It also states that it can occasionally turn itself on at idle which is not a problem.

So I'm less worried and will bring it for a service shortly so it will be checked and hopefully fixed. Will report back once I know what the problem was about.

thanks,