bbutler4

Hello Rennlist Group,

Last Summer I bought my first beautiful 88, 911 with 95K. It runs great however I have a question about the Oil level gauge. After warm up it drops in to the red when I excellerate (5000 RPM. ) . I understand that the gauge is supposed to bounce around but it seams to get pretty low. Even in to the red. It stays up fine at the very top (pegged) of the gauge when ideling. There is plenty of oil in the car. I check after warm up during idle etc. It reads at the full end of the dipstick. The pressure gauge always reads fine.

It seems to have gotten worse since I changed the oil and I also have an oil leak now. Is it possible to have too much oil in the car?

Thanks for your help everybody. I don't have 5 grand to put in this car right now so hopefully it is nothing major.

Bob Butler

old man neri

The oil gauge is a guide. Dip stick is the only real way to check the oil. Gauge will also only be accurate when idling, just like when you check your engine. If you were to check your oil when it was at 5000rpm with the dip stick it would probably read real low as well. You will start to understand better what the gauge is telling you the more often you crosscheck it with the dipstick.

Remember: Warmed up, on level ground, and has been idling for 30 seconds. Check with dip stick. If this shows a good level then all is well.

As for the oil leak, that is a different story. It happens, it's common. Some fixes are easier than others. Where is it leaking?

theiceman

no I think your oil level is fine. if the dipstick says it is correct after it is warmed up and idling when you check it then that is correct. The oil level guage again is only valid when the engine is idling and warmed up . Mine is extremely accurate.

You could have a couple of things going on .

1. someone could have dropped a dipstick in the tank by accident while trying to put it back and it is interfering with the sender. The next time you change the oil bend a coat hanger and see if you can feel anything through the drain plug hole .

2. The sender is simply bad. the guage pegs when the wiper seperates from the rheostat on the sender. You just may have a bad spot. you can buy a sender and replace it fairly easily, Just jack up the right rear corner, take off the wheel . clean the outside of the tank and sender thoroughly before removing it. Take the six nuts off the sender , remove the old one. insert the new one and your done.

Mine used to sit in the red all the time till i replaced the sender , Now it is excellent. it is so accurate i can use the guage by looking through the back window when topping up the oil after an oil change.

rusnak

The oil system is a "dry sump" system, similar to that in aircraft and racing cars.

I agree that the dipstick is the most reliable way to check the oil, and you should always check the dipstick before adding any oil, ever.

You also must know how to check your oil. Make sure the engine is warmed up to at least 180F. The oil thermostat is partially open at that temp. The engine must be idling for about 2 mintues on level ground. The oil should not be outside of the upper and lower marks. I do not let it get higher than 2/3rd high because at 210F when the thermostat opens fully, more oil is dumped into the tank from the oil cooler, raising the level further. Usually I aim for 1/2 full at 180F, but your mileage may vary as they say (everyone does things a little differently).

If it's close to oil change time, you can calibrate your dipstick and gauge (at the correct oil check temp etc) by adding the correct amount of oil.

But some other things need clarification. You say that the oil level gauge drops when you drive to 5K rpm, so it must be working. It's normal for the oil level gauge to flap around like a butterfly when you are driving down the road. This is from oil being poured into the tank while the engine is at operating speed. And you say the pressure gauge is fine. Basically you should see a little over 1 bar per 1K rpm. If the oil level gauge is pegged when you are idling, then I'd say you have too much oil.

Too much oil will cause too much oil pressure, and you can have oil in the exhaust, damage a cat, bend a connecting rod or damage a main bearing, blow an oil seal or o-ring, and on and on. It pays to learn how to check the oil level, and always follow that procedure.

Daviboy

Your oil level is fine as long as you read the stick at operating temp idle dont even worry about the gauge. I gave up on mine about a nanasecond after I bought her. Also mine did weird things after an oil change as well. But as the goodfellas say 'Don worry about it'

JackOlsen

A detail: you want to fill it to the midway point between the two marks, not to the top mark.

theiceman

I disagree on some points but if we agreed on all there would be no discusion :

oil level has nothing to do with pressure ( othe rthan if you didn't have any ) . Pressure is a function of the oil pump. bearings, and engine clearances.

Weather the thermostsat is partially or fully open will not magically create more oil in the tank and less in the crankcase, once it's warmed up it's warmed up .

But anyway all this said sounds like you are fine. On my car Ican actually fill the oil to the full MArk with no worries. I replaced my oil sender and matching dipstick which moved the "full" mark lower by about a litre. This was an OE dipstick so it looks like Porsche at som epoint my have realized what Jack is talking about. I never spill any oil into the intake in hard cornering and all is good.

Ps that is your tell tale sign if you have overfilled. The vapour recovery line that runs from your oil tank to oyur intake will allow oil in on cornering if you have overfilled your oil and you will look like a Bond Car. Sounds like you are fine.

rusnak

I would agree that it's almost not possible for a veteran 911 owner to have oil level problems. Checking and watching oil level becomes intuitive, at least it has for me.

I am always taken aback at the adjustment that my friends who just bought their air cooled 911s have to make, however. For example, I have a friend who I help occasionally that bought a 911SC. Not long after he got it, he thought it would be a good idea to check the oil on his baby. Oh no, not enough oil. He added about a gallon of oil until it was over the low mark. Started it up, and according to him, it smoked like Tulare fog. Well, he damaged his motor. Too much oil. He took it to a local Porsche mechanic named Dave Tiboni (may he rest in peace) and got it re-ringed, new valve, new bearings, etc. and basically put back together on the cheap for about $3,500.00 including gaskets.

I asked him how he thought the car needed that much oil. He said he checked it the same way he checks his Honda......

theiceman

definitely too much oil .... in the intake

actually too much oil in regular wet sump applications is even worse than ours. For us as you mentioned you create the worlds biggest mosquito fogger, and if it gets really bad you are pouring oil into the intake ( oil doesn't compress well ) and that gets expensive.

In regular wet sump cars all the oil is in the crancase and the crank will turn into foam for you in a hurry . now put that through your oil pump and see what happens ... yuk .....

Rusnak we will never see the end of guys coming on saying " i just filled the oil as the prvious owner let it run too low and now it smokes like Bond car "

part of the hazing I guess ..... I did the same when I got my first 911 . except I was dumb and decidedd to let a little out of the tank from the drain plug... you would be amazed how much oil the insdie of your winter jacket will hold when it fills up via the sleeve. it sure made me warm for a few seconds but it was all tears and garbage bags after that.

rusnak

another funny story is my friend Jeff (Nutmeg on Pelican) who is a professional aircraft technician. Jeff owns a nice 3.2 Carrera. He's obviously very savvy mechanically. I was there when he did his first ever oil change on a 911. He bought a few cases of Brad Penn (we were calling it Brad Pitt oil to peeve him off).

Anyway, he goes to remove the drain plug, and I start to back away. He had the right sized drain pan (I'm not that mean), but it went "blooooshh!" all over his arm, face, nice clean floor, etc. He was scrubbing his floor later with towels and Brakleen and I go "you've been Baptized".

Ha ha ha...funny stuff I tell ya, watching the first 911 oil change.

MUSSBERGER

Important detail^^^^^^^^^^

james brown

i removed my oil qty. sender and gage and put in a volt meter. You will get the hang of checking it over time. always keep it on the high side of the two marks on the dipstick when it's warm and idling around 1000 rpm.
your not checking the oil like an old ford, it's like checking the life blood of a fine insterment. It's an art...

james brown

i removed my oil qty. sender and gage and put in a volt meter. You will get the hang of checking it over time. always keep it on the high side of the two marks on the dipstick when it's warm and idling around 1000 rpm.
your not checking the oil like an old ford, it's like checking the life blood of a fine insterment. It's an art...

glenncof

I've put on over 180K miles during 17 years of ownership and oil level has me constantly guessing. It's so inconsistent. I get the highest reading when it's really hot, running at first hash mark(on '85). I can't get it there unless almost 65F ambient. This has caused me to go 10W40 in winter from 20W50 and oil consumption went down (?). I'm still trying to understand....maybe I need a few more years.

rusnak

Glenn, that is normal. That is also why I was suggesting you leave a margin. At 180F you aim for the middle of the range, so that an extra half quart can come from the front cooler. When the oil temp gets to 210 you'll notice more oil in the tank than you'll ever get all winter long. I'd say you and I have similar 911 driving habits.