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Hi guys, I'm a proud owner of a beautiful 1984 Carrera cab. Being new to the air cooled 911 world I have a million questions about my car. My biggest concern right now is the oil level.
Before you ask, yes, I have searched the forum and most likely found the answer but this being the oil level we are talking about, I'm seeking confirmation from the experts.
A little background. I'm the fourth owner and the car has lived its whole life in British Columbia's interior. (Kamloops). It has been serviced by the same mechanic for the past 20 years. The car is extremely well documented. I am presuming that this mechanic has changed the oil the same way for the past 20 years...
Here is my concern: the mechanic was very helpful and informative during the PPI. He told me that it is critical not to overfill the oil (as I have read here). He told me that when warm, the oil gauge should read "just above the red section" and the dipstick should read "just above the first Mark".
I took the car out for a short ride and noticed the oil level in the red. I immediately turned around and checked the oil at home.
Now I've read my owners manual and checked the oil level accordingly. Here were my results. Keep in Mind that the oil was changed on Thursday by the mechanic in question.
At idle before checking
Oil is about 1/2" above bottom mark
At idle after checking
Now, I know the difference between both marks is 1.75 litres. Would you add oil? According to my invoice, the mechanic put 10 litres of oil in.
its fine..
I always fill mine to the fill mark and it sits at the top of the guage and have never had overflow but everyone will tell you put it beween , yours is fine. you have to let it ide for 30 seconds or so after fully warmed up for the tank to stabilize. your car is fine.
I wouldn't worry about it. The first picture shows low but the car is also not up to temperature. The engine must be fully up to operating temp and be on level ground in order to get an accurate reading. I wait until the oil temp gauge is atleast on the first white mark before checking.
according to my mechanic the oil level gauges become unreliable. anyway, you must check the oil while engine is warm and RUNNING. Oil level should be between low & high markings in the dip stick. My gauge usually shows approximately correct level after idling for awhile.
all of the above correct, gauge not always perfect, must be up to temperature, check on level surface while engine running, also look at your pressure gauge, you want to see that up around 4-5 at speed and 3-4 idling
all of the above correct, gauge not always perfect, must be up to temperature, check on level surface while engine running, also look at your pressure gauge, you want to see that up around 4-5 at speed and 3-4 idling
sorry but I just don't agree with this.
Maybe cars are different but if I had 3-4 pressure while idling at 850 rpm at engine temp I would be quite concerned.
In fact many early Porsches the pressure is so low the idiot light flickers and this is considered normal.
I think 1-2 at idle while warmed up is fully acceptable.
Maybe cars are different but if I had 3-4 pressure while idling at 850 rpm at engine temp I would be quite concerned.
In fact many early Porsches the pressure is so low the idiot light flickers and this is considered normal.
I think 1-2 at idle while warmed up is fully acceptable.
I agree here.
OP - you mentioned it reading low while you were out driving. It absolutely _should_ do that. While the engine is spinning above idle, more oil will be taken from the tank and circulated through the engine. When everything is good with the engine and oil, the oil level gauge should read low at all times other than under the correct test conditions.
The gauge has been reported by many to be unreliable, but mine always matches the dipstick exactly, so I tend to rely on that. If I were you, I would figure out for yourself whether you think your gauge is reliable and don't just listen to reports about others' inaccurate gauges before writing it off. I would say that the dipstick should be considered the best measurement you can get, though.
To accurately check oil level, the car must be level, the oil must be at operating temperature (both so the thermostat is open and so the oil itself has expanded with the temperature rise), and the engine must have been running at idle for long enough to let the right amount of circulating oil collect in the tank (at least 30 seconds, more may be better).
I find it most convenient to do this check when I pull into my garage after a drive - level ground, warmed up, I just let it sit and idle for a little (which is probably a good cool down anyway), check the gauge and call it good, unless ...
If I see the gauge reading down near the red area, I leave it idling and double check the dipstick. When that (always) confirms the gauge, I add a quart, which brings the level closer to the high end of good. With my oil consumption rate, this will last me another ~2500 miles. If my car were showing the photos yours does (and it were fully warmed up, which I can't tell since the temp gauge is not shown in the second photo), it would be borderline, but I myself would add a quart. I'm sure others would not, and I would not necessarily disagree with that.
I just rolled past 20 years of owning this car, and it has not blown up yet. In fact other than an alternator replacement (that was self-inflicted), it has needed nothing but regular maintenance throughout all this time.
I've been told to completely ignore the gauge and go by the dipstick.
It's recommended to check the dipstick every few days of driving... or every 200-500 miles (depending on how often you drive it, how you drive it, and where you drive it).
The fear of the Porsche Gods was put into me when I was told to NEVER go by the gauge or I'll end up putting too much oil in the engine which is catastrophic for these engines.
I've been told to completely ignore the gauge and go by the dipstick.
It's recommended to check the dipstick every few days of driving... or every 200-500 miles (depending on how often you drive it, how you drive it, and where you drive it).
The fear of the Porsche Gods was put into me when I was told to NEVER go by the gauge or I'll end up putting too much oil in the engine which is catastrophic for these engines.
My advice is to find a level place to check the dipstick after a long fun day of driving and just before you put her away. Check, top off, and she's ready for the next run.
After a while you will get a sense of how many days of driving you can go without having to check it and if you log the miles you will know how much consumption you are dealing with too.
actually that's a great question Rick and I imagine it might. But how much it will change it is not known. but with so much oil in the tank I cant imagine its a huge deal. I should do a test next year for you and just dial it up the idle to 1500 and have a check. she is pretty well done for this year though
Sorry for the hijack bump, but my 74 is idling very fast like 1500 rpms. I imagine a vacuum leak or something.
Anyhow, my question is if my idle is that high is that going to mess up / understate the oil read, on the gauge or the dipstick?
A good way to answer this would be to find someone with a 74, have them hold idle at 1500, and measure the dipstick. Whatever that shows is likely to apply to your car.
11-07-2016, 04:00 PM
Oil level question
