1979SC GREEN oil light / oel light - Illum.

[reed_barrington]

Today Im discovering a new issue on my 911 sc.

On startup my Green OEL light AND emergency brake light are staying on. Obviously I put the lever all the way down but the E Brake light stays illuminated. I got out of the car and I do see a little smoke coming out (nothing crazy) from the muffler...as well a bit of water dripping.

Im a bit concerned of my oil pressure / Druck Press Gauge. If I rev the car to 3/4K it hits about 2.3 pressure. Actually, I never see it going any higher than about 2.3 EVER at any speed. any thoughts would help..

Also.

After the green light and E brake light are on I decided to shut off the car. Once I started it up again they both were off. I drove it for a bit, nothing lit up.. But next start up it happened again. this is a new experience.

1979sc and the oil its holding is 5W-30 mobile 1.


thanks in advance.



reed.

[lv600]

This is just my opinion, but here is a stab at your issues.

The oil is a little thin for my taste. 5W-30? Granted, I'm in LV with high ambient temps, and I don't know your locale, but I run 20W-50 and have no oil issues. My oil press tracks the RPM, 1 to 1. idle is about 1 on the oil gauge, and it ramps up when the throttle blips.

Personally, I would think the 5W-30 is a little thin for our engines, but I could be wrong.

You could go as far as checking the oil sender and seeing if it's stuck by grounding the wires together, and see if the light goes out. I would start there.

As for the e-brake, I would also check the switch at the handle and work backwards. If the switch and wires are fine, it could be a start of a problem with your master cylinder, or something simple like low brake fluid(?)

Not a lot of information to determine the correct scenario, but this should get you started in the right direction.

Hope this helps!

[reed_barrington]

thanks for the response. The E brake light and Green light seem to be in-synch.. I feel like its telling me... Do not drive.. theres an Oil issue. When one goes off they are both off together.. never just one.

The oil seemed thin to me too but thats what my mechanic was pushing.
I understand rpm to match Druck pressure on throttle. Would thinner oil throw that pressure off slightly or to the point it will not pass 2.3 of 5 Druck press.

curious...anyone?


thanks.

reed.

[reed_barrington]

Sure this could be a bug or a electric wiring funk of the day.

But i'm surprised of all the 911 pelicans out there to not get many answers on this. So no one has ever had the emergency brake light stay on as well as the green OEL / Oil light remaining on after startup?

thanks


reed.

[lv600]

IIRC, mine does the same thing, as the brake light is above the seat belt light in the center of the dash, above the radio slot.

I can't remember if the brake light (with the green oil light) is even connected in my 78. I don't think it's even there.

The PO could have wired them together.

Pull the gauge and see if the 2 lights are connected, which could have been changed by a PO.

Also, you can check the oil pressure switch without starting the engine, then you can see if your oil switch is faulty.

Unless someone else has some better ideas.

Hope that helps.

[kerthunk]

Well, the oil warning light is controlled by a green/white wire that goes back to the oil pressure switch (not the oil pressure sensor) that will go to ground when there isn't enough oil pressure, turning on the light. The switch is one of the elements of the famed "triangle of death" that is located under your CIS, making it a bit of a pain to swap out easily. From the oil warning light, the green/white wire then goes to the parking brake indicator circuit. This is actually where the +12v comes from for the oil indicator light. So, they are connected to each other electrically.

[reed_barrington]

so then if they are linked and both illuminated then its likely a wiring glitch..? Its not saying.. "stop... do not drive" if it was just the green chances are its a real issue?

thanks

reed.

[kerthunk]

Actually, I believe that it IS trying to tell you to "stop...don't drive". Wether it is correct or not is what we need to figure out. There are 3 switches that can cause the parking brake light to illuminate: oil pressure, parking brake and brake light switch.

I would recommend looking through all of the bits of the oil system. Could be a faulty pressure switch, too thin oil or a failing oil pump. 2.3 bar of oil pressure max is REALLY low. I believe that the thinner oil can cause the oil pressure to be low. I know that as the oil heats up and looses viscosity, the oil pressure will go down a bit. Changing out the oil is probably the easiest thing to do, most folks around here are using 20W-50 or something similar. Next would be to replace the oil pressure switch. It is fairly common for them to have an issue, especially if you disturb them. Not a fun place to dig into, but it is a cheap part.

That's my 2 cents anyway...others with more experience may chime in.

[reed_barrington]

thanks john for the advice. I'll be looking into those recommendations. I see we have pretty much the same car. Its a real pleasure to drive.


reed.

[kodioneill]

I agree with the post that says use oil with a higher viscosity. I would never use synthetic in a air cooled engine. (some if not many would disagree) .

[reed_barrington]

thanks. Is there a certain oil I should buy? I should try 20W-50?. I think my mechanic put in the lighter oil thinking it helps from the pressure/weight for the 33 year old car of any leaks?

thanks

reed.

[kodioneill]

If you do a search you'll find many discussions on oil. I use Cenpeco or Rotella.

[kerthunk]

I use Brad Penn 20W-50 in mine. I might need to switch since it is getting harder to find and pricier in my neck of the woods. Looking for non-synthetic and lots of ZDDP. Don't ask too many questions about oil on the forums here though....we don't want to attract the oil zealots and end up with another 50 page thread!

Good luck and report back with your findings!

[pete3799]

I think you'll find that the alternator light and parking brake light are the ones that are connected.
Is it possible that the bulbs are switched in the back of the gauge?
When the "oil" light comes on (with the car running) put a volt meter on the battery and check your voltage.
This could be an alternator problem.

[kerthunk]

Originally Posted by pete3799

I think you'll find that the alternator light and parking brake light are the ones that are connected.
Is it possible that the bulbs are switched in the back of the gauge?
When the "oil" light comes on (with the car running) put a volt meter on the battery and check your voltage.
This could be an alternator problem.

The alternator light is triggered by the blue wire going directly to the alternator and is not connected to the parking brake light. The factory wiring chart verifies this.

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_78SC_USA.pdf

If you follow track 95 (in the yellow bar at the bottom of each page), F1 is the oil pressure switch, going up to K3 which is the oil pressure light, then the green/white is going over to the big box (the seat belt/parking brake light assembly) with K7 being the parking brake light. The alternator light is K2 which if just up and to the left of K3. It is fed by the blue wire from the alternator. The red/black is the common that connects most of the dash indicators together. The parking brake light has no connection to the alternator (and it's indicator) except for the +12v feeding the entire car.

[pete3799]

Originally Posted by kerthunk

The alternator light is triggered by the blue wire going directly to the alternator and is not connected to the parking brake light. The factory wiring chart verifies this.

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_78SC_USA.pdf

If you follow track 95 (in the yellow bar at the bottom of each page), F1 is the oil pressure switch, going up to K3 which is the oil pressure light, then the green/white is going over to the big box (the seat belt/parking brake light assembly) with K7 being the parking brake light. The alternator light is K2 which if just up and to the left of K3. It is fed by the blue wire from the alternator. The red/black is the common that connects most of the dash indicators together. The parking brake light has no connection to the alternator (and it's indicator) except for the +12v feeding the entire car.

yup..... i got confused.
I was trouble shooting my oil pressure idiot light (lack there of) one day and THAT'S when i found that the two were connected.
I just replaced my alternator and had that on my mind. Sorry.....carry on.

[S2GART]

5W-30 should only be used if the outside temp does not get above freezing. I am referring to the oil chart in my owner's manual. Whether one uses synthetic, semi-synthetic or dino oil, the required viscousity doesn't change. The aforementioned 20W-50 is good for temps down to about 18 degs. If you can't find 20W-50, you could go with 15W-40, typically sold in 1 gallon jugs. This will cover you for temps ranging from about 5 degs to over 100.

[reed_barrington]

Thanks everyone for your time on this so far!

[mydangemail]

This is happening to my car now. Any idea on the problem? Thanks for your time.

[PeteKz]

Need more info. What model/year of car, what mods, any recent work, etc. Have you changed anything recently? Is it a new problem? Did it occur gradually or suddenly? And what EXACTLY are your symptoms.