Ed Hughes

The gauge relationship to the dipstick varies from car to car and should only be used as a reference when the owner fully understands that relationship. Gauges and senders do go bad, and are no sub for the stick.

theiceman

+1000

you have to be very confident and know your car well before you can really believe that guage . coz an engine is a terrible thing to waste.

rusnak

All of the above is good info.

Only thing to add is that it's not so good to add oil all the way to the full mark. Halfway is better.

The reason is that when the oil is hot, and if you peg the oil pressure relief valve, then it'll shunt oil around the oil cooler to save the cooler. This means that your oil is not getting cooled at all.

Steve Weiner-Rennsport Systems

Good one, indeed,....

S2TGART

Of all the oil change threads I have read over the years, there is still one thing that confuses me. Everyone says add "x" amount of oil, let it warm up and recheck and add as needed.

The amount of oil needed for each engine is a known quantity. Why not just put in that amount? My SC calls for 10.75 quarts of oil. So I put in 10.75 qts of oil and call it good. What is there to check? By saying "add as needed" is like saying that at each oil change the amount of oil your engine needs, changes.
Is there something I am missing here?

1986 Targa

Does the 10.75 value address the residual oil in the oil cooler and oil lines?

Ed Hughes

It's personal preference on the procedure. I put exacty 10.5 qts in for many, many oil changes, and was always right on the money (splitting the two marks).

theiceman

Yes it does vary as there is always some trapped in the cooler for example , and depends how viscous the oil is etc. I have found that if i driver around the last kilometer to spike the oil temp and make sure the thermostat is fully open and imeadiately crack the plugs when i get out I can pretty well put 11.5 quarts back in .

S2TGART

I mis-typed. It's actually10.57 quarts.
Page 91 of the owner's manual states ...... "Quantity at oil change: 10.57 U.S. qts or 10 liters."

Off the top of my head I don't know the total oil system capacity, but they clearly state what it takes for oil changes. Obviously the temp of the oil affects it's viscosity/level, but Porsche knows you're not putting 185 deg. oil in. So if they say put in 10.57 qts of oil out of the bottle (room temp.), then there shouldn't be a need to second guess that. Put the prescribed amount in and call it good. Obviously when checking the oil level on the dipstick, you have to again, follow the manual and check it when it's up to temp.

Once one has done 1 oil change, you would know how much your particular engine takes. Then for future oil changes one would simply put that amount in without having to get the new oil up to 185 degs to check that you put in the right amount.

theiceman

i agree but always put most in then top it up . Call it my guilty pleasure.. somewhow just dumping it all in the tank cold and hoping it doesnt overflow as the thermostat hasnt opened to allow it into the cooler yet sits in the back of my mind ... no facts to siupport that however .. i just feel better doing it my way

S2TGART

I too agree, all of this comes down to what one feels better with. With my dipstick, I used my Dremel and made a mark at the mid point between high and low, since that is where it is considered to be the best level. With the mark I made, I can gauge any oil usage.

What I lost focus of, as with many of these thread, is the original question/subject. The oil level gauges are notoriously inaccurate. There are times when I am doing 70 mph and the oil level guage indicates that I have no oil. However the pressure is fine, the oil temp is fine and I know for a fact there is oil in there. So as mentioned by others, your eyes are more accurate than the gauge, look at the dipstick.

theiceman

oh well this may be usefull to many then .,. the oil level guage is ONLY to be used when idling with the engine warm . it is NOT for when driving. Mine is dead on accurate as I replaced the sender and the dipstick together incidentally the new dipstick full mark is a lot lower ( probaby Porsche realized the overfill condition. )

But i only check it after coming home an pulling it into the garage ..

but never ignore your stick ... !

Ed Hughes

To further ice's post: When you're flowing oil through the motor, the level gauge does indeed drop to what one may perceive as zero. It's just like the dipstick, only useful when on flat ground, warm and at idle for a short spell. One needs to correlate it to the stick on each car.