1973 oil level question

[dicklague]

Yesterday my red emergency brake light started blinking. I thought the brake was up a notch and that was not the case.

I then suspected it could be the oil tank was down and there is as switch or contact in the oil tank that trips this light to warn you. I am due an oil change and it probably is a bit low.

Today I did an oil change and so far the light is out, but I have not warmed it up of driven it for a long time.

I have not looked at the wiring diagram yet, just wondered if anyone knew if the '73 911 is wired this way.

I have only owned the car for 16 years and never noticed this!!

Thanks.

[Spumato]

Are you referring to the light at the bottom of the gauge?

[dicklague]

Originally Posted by Spumato

Are you referring to the light at the bottom of the gauge?

No there is a large red warning light at the top of the gauge that flashes when the emergency brake is on.

[James Brown]

nope you have to watch the quantity, or check the oil in the approved way once a week, in fact, i removed that silly oil sender gage and put in a voltmeter from NHS way better.
that pesky brake light needs to be traced out to verify its not the brake circuit or a faulty parking brake switch.

[dicklague]

Originally Posted by James Brown

nope you have to watch the quantity, or check the oil in the approved way once a week, in fact, i removed that silly oil sender gage and put in a voltmeter from NHS way better.
that pesky brake light needs to be traced out to verify its not the brake circuit or a faulty parking brake switch.

How does a voltmeter measure oil quantity?

My gauge works great and I check it manually too.
I have a digital voltmeter and a digital oil cooler temp gauge as well.

I guess my light is just a coincidence.

[wayner]

Originally Posted by dicklague

No there is a large red warning light at the top of the gauge that flashes when the emergency brake is on.

My 73 does that too. I always just figured I'd wired something wrong and haven't gotten around to looking into it. I know my mechanical systems are all good so I just assumed it was a good reminder for me not to drive away with the brake on.

I'll be watching here to learn more.

[E Sully]

There is only a sensor for pressure gauge in the 73, no idiot light. The indicator at the top of the gauge is for parking brake and sensor on the master cylinder.

[cmcfaul]

My oil level gauge always was super accurate. Only looked at the dip stick when doing an oil change and once in a while to validate what the gauge was saying.

Chris

[dicklague]

Originally Posted by E Sully

There is only a sensor for pressure gauge in the 73, no idiot light. The indicator at the top of the gauge is for parking brake and sensor on the master cylinder.

Thanks for the diagram. Where is the brake warning switch and how does it work? Is it a fluid level sender?

[Quickstep192]

Is there a way to calibrate the in-dash oil gauge? When my oil level is just right, my gauge reads low.

[dicklague]

I found that if I touch the footbrake the warning light goes out. I guess it pressurizes the system and closes the switch. I will have to look for the switches location.

[E Sully]

The brake warning switch is on the master cylinder.
I would think the only way to calibrate the oil sender would be to bend the arm on the sending unit in the oil tank.
I would also ad that the later replacement sending units come with a note to use the newer dipstick. This is due to Porsche using a lower level of oil in the tank. The newer dipstick has the full mark stamped lower. Most likely done for the reason that most early Porsche owners found that oil was being pulled into the intake when the oil on early cars was filled to the maximum mark on the dipstick.

[dicklague]

Originally Posted by E Sully

The brake warning switch is on the master cylinder.
I would think the only way to calibrate the oil sender would be to bend the arm on the sending unit in the oil tank.
I would also ad that the later replacement sending units come with a note to use the newer dipstick. This is due to Porsche using a lower level of oil in the tank. The newer dipstick has the full mark stamped lower. Most likely done for the reason that most early Porsche owners found that oil was being pulled into the intake when the oil on early cars was filled to the maximum mark on the dipstick.

Thanks will look for it.

[HarryD]

My brake warning light started flashing when the warning switch on my master cylinder failed.

To see if it is the master cylinder switch, jack up car, and remove the left front wheel. Support the car properly. You will see the master cylinder and switch behind the wheel. Make sure your hand brake is off. Turn the car on, see the flashing light. Pull the wire off the switch and see if it stops.

If it stops, you have a bad switch. Get a new one and change it out (you do not need to drain the brakes).

If it stays on, it is the adjustment for your handbrake.

[HarryD]

Originally Posted by E Sully

The brake warning switch is on the master cylinder.
I would think the only way to calibrate the oil sender would be to bend the arm on the sending unit in the oil tank.
I would also ad that the later replacement sending units come with a note to use the newer dipstick. This is due to Porsche using a lower level of oil in the tank. The newer dipstick has the full mark stamped lower. Most likely done for the reason that most early Porsche owners found that oil was being pulled into the intake when the oil on early cars was filled to the maximum mark on the dipstick.

Interesting. I recently changed my oil tank level sender. Now, when the mark on my original dipstick is at the min line, the gauge indicates in the middle. It is telling me that I an 2 quarts low but lets me know that there is still oil in the tank. When I add a quart, the gauge shows full and my dipstick is halfway between min and max.

I like this.

[Spumato]

Not sure if this was asked but when are you checking your oil level?

The engine has to be warm (180+ degrees) prior to being able to obtain an accurate read.
Anything less, and you are working with incomplete data.

The heating rule also applies for oil changes. The oil has to be warm to drain also.
Anything less, and you won't be able to clear the engine & reservoir(s) out completely.

[HarryD]

Originally Posted by Spumato

Not sure if this was asked but when are you checking your oil level?

The engine has to be warm (180+ degrees) prior to being able to obtain an accurate read.
Anything less, and you are working with incomplete data.

The heating rule also applies for oil changes. The oil has to be warm to drain also.
Anything less, and you won't be able to clear the engine & reservoir(s) out completely.

Yes, car properly warmed and on a level surface. Allow to idle (around 750-900 rpm) for 30-60 seconds prior to pulling the dipstick. Wipe dipstick, dip and read.

FWIW, I have not noted a significant volume difference between draining the oil hot or cold. It just takes longer when it is cold.

[bavaria911]

Question: I replaced the sending unit inside the oil tank of the 1971 Targa due to the gauge pegging to 8 when I turned the key to on position. The replacement seems to work, I warmed the engine to 180 and added oil to the 6 level on the gauge with dip stick reading okay. But as I drive the car, the gauge reads in the red near 5.
Is that correct? As I come to a light the gauge goes to the middle...6.
Scott

[RSTarga]

Dry sump, oil level in tank drops when above idle.
Are you looking at your oil pressure gauge or your oil level gauge?
How many quarts did you put in after oil change?
Level on dipstick should be between the 2 lines when engine is warm at idle.

[bavaria911]

Looking at the oil level...it drops upon acceleration to 5 or sub 5.
Is that normal?
The oil pressure is fine.
The dip stick reading as mentioned above is good.