germanspeed

So i had posted a few weeks back about my oil being over filled so i drained a little bit and went and got a full tune up and oil change. I'm running Mobile1 synthetic in my 91 964 C2. The problem is, when i first got my car back from the mechanic it would show an oil level on the gauge a little bit over halfway when at idle and at operating temperature. However, now the oil level is shooting all the way to the top of the gauge when at idle and operating temperature. I have tried to check the oil level on the dipstick but i am finding it a little hard to read. I was starting to get nervous that i was getting gas blow through which would increase the oil level. Is that even possible within one week after the oil change? Thanks for any help provided....

dave morris

Huh? Not familiar with 'gas blow through'. Can you elaborate?

Scotty964cab

I wouuldn't be concerned about the high reading on new oil. The outside temperature will affect the viscosity as well. As the oil breaksdown and the ambient temperature rises that gauge will travel more.

Porsche917K

Just ignore the guage all together. It's nearly useless IMO. There are so many variables to why it will be to high or low at any given time. Just check the level with the dipstick periodically when the engine is warm.

ilko

FYI, the gauge has been spot on 100% in both of my 964's.

jimq

mine seems to be accurate as well

TR6

Mine too. You just have to know how to use it (same with the dipstick). Completely warmed up with thermostat open, idling for a couple of minutes on level ground.

68CGPlt

You could do a few things here. First, I would confirm how much oil was added at your service. If all is well, then take it out for a drive and recheck with the dipstick as this is the most reliable method. On both of mine I've found that the dipstick will show a little oil residue when the oil is actually low (gauge in the red at full operating temp on level ground), however when filled to the correct height I noted the dipstick indications to be obvious and easily readable. You can also remove the right rear forward fender liner and then pull the cover to the oil tank where the mechanical float switch (not sure of the correct terminology) resides. Once open, turn the key to ON (without starting) and manipulate the mechanical float (if you do this be careful everything is clean and don't drop anything into the tank as it's very much open). I was able verify that my gauge would work through it's entire range without spiking (which may indicate some issue with the electrical output or something upstream of the switch itself).

Anyhow to make a long story endless, all of these items combined enabled me to comfortably add more oil until correctly filled. Now I'm confident in the fact that the gauge and dipstick readings correspond with one another. However, I still rely on the dipstick as the final authority for a proper oil level reading.

Streetfighter

I just wanted to add I use the gauge and it is accurate.

tbennett017

The gauge is accurate for me too. Lots of shops mess this up, and oil will expand a lot. I don't really understand the rationale behind Porsche's setup here. I'd like to be able to check the oil at a cold volume too... (unless I am missing something critical about oil here...)

Adrian Streather's book reprises Porsche's original method for an oil change/check. Drain, then its 6 quarts before the first restart, idle til hot, and add up to another 3 (approx). I get it right every time.

ilko

I add 8 then restart, then add another 3.

I always buy 12 quarts of oil. 11 go for the oil change and the last one goes in during the 3-4K miles I drive the car every year.

68CGPlt

I follow the same process as ilko and it's work well for me.

jim_l

my oil level gauge was erratic, caused me an overfill. replaced the sending unit. gauge works ok now. does your car smoking at all.

Bull

Both the oil gauge and the dipstick require about the same amount of detail as to the management of the conditions when you check them, and once you take a few readings to calibrate the relationship between the gauge and the dipstick for your car, the gauge is very useful.

My gauges on several 993s, two 964s and a Carrera Cup have all been accurate with regard to the dipstick.

springer3

My gage is reliable.

You need to know how to read it, The level is valid only when the engine is warmed-up and idling. Oil expands a lot as it warms up, and only when idling is there enough oil in the tank to read the level. It is normal for the gage to dip into the red zone when the engine is cold or you are at speed. It should never go above the top mark when idling. You are too full if it does.