Oil Gauge and Stick Ranges
08-17-2006, 02:31 PM
#1
Drifting
Thread Starter
Oil Gauge and Stick Ranges
I was just browsing through the 911 Carrera 4 '89 Information Technik Service manual (WKD 495 121) and found this:
So, the stick reads 1.75 liters and the gauge reads 1.25 liters (+0.3 to -0.2 liters).
I wonder why we all get oil overflow if we fill up to the MAX on the gauge, yet Porsche recommends (at least in '89) that level?
At the very least the range of the gauge and stick are interesting.
Cheers,
Dave
Oil Level
Oil level control is accomplished at operating temperature and idle speed only via an electric oil level display instrument in the dashboard (approx. 90 degrees C = 1st mark on temperature gage). The car must be on a level surface during oil level control.
The amount of oil between the MIN and MAX marks on the oil dipstick is 1.9 quarts (1.75 liters). The MIN / MAX marks on the oil dipstick cover a larger range than the oil instrument display. The range monitored by the instrument begins approx. 0.3 quarts (0.3 liter) above the MIN mark of the oil dipstick and ends approx. 0.2 quarts (0.2 liter) below the MAX mark.
In engine inspections oil must be filled until the level reaches the MAX mark on the instrument, at idle speed and operating temperature of the engine (equal to approx. 25 mm below the oil dipstick's MAX mark). The distance between the MIN and MAX marks on the oil dipstick is about 110 mm.
Oil level control is accomplished at operating temperature and idle speed only via an electric oil level display instrument in the dashboard (approx. 90 degrees C = 1st mark on temperature gage). The car must be on a level surface during oil level control.
The amount of oil between the MIN and MAX marks on the oil dipstick is 1.9 quarts (1.75 liters). The MIN / MAX marks on the oil dipstick cover a larger range than the oil instrument display. The range monitored by the instrument begins approx. 0.3 quarts (0.3 liter) above the MIN mark of the oil dipstick and ends approx. 0.2 quarts (0.2 liter) below the MAX mark.
In engine inspections oil must be filled until the level reaches the MAX mark on the instrument, at idle speed and operating temperature of the engine (equal to approx. 25 mm below the oil dipstick's MAX mark). The distance between the MIN and MAX marks on the oil dipstick is about 110 mm.
I wonder why we all get oil overflow if we fill up to the MAX on the gauge, yet Porsche recommends (at least in '89) that level?
At the very least the range of the gauge and stick are interesting.
Cheers,
Dave
08-17-2006, 03:08 PM
#2
Three Wheelin'
Join Date: Dec 2003
Location: Rancho Palos Verdes CA
Posts: 1,569
Likes: 0
Received 2 Likes
on
2 Posts
I only use the guage to know when I am about 1 qt low...I always use the dip stick for actual level...
Interestinginfo though. I sort of figured that was how it was reading...
Interestinginfo though. I sort of figured that was how it was reading...
08-17-2006, 03:24 PM
#3
Technical Guru
Rennlist Member
Rennlist Member
Originally Posted by dfinnegan
I wonder why we all get oil overflow if we fill up to the MAX on the gauge, yet Porsche recommends (at least in '89) that level?
08-17-2006, 05:07 PM
#4
Drifting
Join Date: Jun 2006
Location: Dallas/FortWorth Texas
Posts: 3,438
Likes: 0
Received 1 Like
on
1 Post
I still can't figure out the logic (if there is any) behind the oil level gauge readings in my 93 RSA. I understand that the car needs to be at operating temperature and at idle on a level surface. But even then, sometimes the needle on the gauge moves up partway, and other times it just stays at the bottom. And even when it does move up partway, it isn't to the same level each time during the same day. 
08-17-2006, 08:02 PM
#5
Rennlist Member
Join Date: Feb 2003
Location: Albuquerque, New Mexico, USA
Posts: 1,004
Received 109 Likes
on
64 Posts
I can not read the dipstick to save my ****.
When and I get my car back from service after an oil change, the gauge will always read to the to the top (when the car is thoroughly warmed up, level ground, etc.).
I have questioned my wrench about this (he is a very experienced Porsche mechanic) and he says that he DOES check the level via the stick.
And I find that, if the level via the gauge gets to about the 1/2 way mark, one quart will bring it back to the level it is after an oil change.
And I have never had an overfill situation.
So, I made the assumption that my gauge simply reads high, but I will say that it seems that my car agrees with the quoted information from the OP.
Brian
When and I get my car back from service after an oil change, the gauge will always read to the to the top (when the car is thoroughly warmed up, level ground, etc.).
I have questioned my wrench about this (he is a very experienced Porsche mechanic) and he says that he DOES check the level via the stick.
And I find that, if the level via the gauge gets to about the 1/2 way mark, one quart will bring it back to the level it is after an oil change.
And I have never had an overfill situation.
So, I made the assumption that my gauge simply reads high, but I will say that it seems that my car agrees with the quoted information from the OP.
Brian
08-18-2006, 12:41 AM
#6
Even if my gauge is at the mid way mark, I still check the stick every other week to make sure. It is a bit harder to get the car to operating temp in winter (esp this last spring in LA) but overall the stick is the better way to check oil level.
08-18-2006, 01:35 AM
#7
Technical Guru
Rennlist Member
Rennlist Member
Here's a copy of a post that I made to the 993 forum, it should (hopefuly) be correct...
If you look inside your oil tank you'll see that the dipstick is located directly next to the oil level sensor. The stick enters the tank at an angle and the sensor is also mounted at an angle.
As the temperature of oil increases so does the volume. At ~194F/90C the difference between the empty and full marks on the dipstick and your dashboard gauge should match the level difference listed on the engine compartment sticker (someone (Adrian?) mentioned the sticker was wrong in the 964, not sure if that also applies to the 993). So if the oil is at ambient 60F the level would read lower than expected and if the temperature was at 250F it would read higher.
If you look at the sensor itself there is not much to it, basically a potentiometer with a resistor track?
Originally Posted by dhicks
What do you mean and what is the relevance......
As the temperature of oil increases so does the volume. At ~194F/90C the difference between the empty and full marks on the dipstick and your dashboard gauge should match the level difference listed on the engine compartment sticker (someone (Adrian?) mentioned the sticker was wrong in the 964, not sure if that also applies to the 993). So if the oil is at ambient 60F the level would read lower than expected and if the temperature was at 250F it would read higher.
If you look at the sensor itself there is not much to it, basically a potentiometer with a resistor track?
Trending Topics
08-18-2006, 11:20 PM
#9
Jason,
I'm very curious. I've been on this board for a while and am always amazed at how much info you have and know about these cars. How do you know all the ins and outs of these great cars? You simply amaze me with your breadth of knowledge.
All the best,
I'm very curious. I've been on this board for a while and am always amazed at how much info you have and know about these cars. How do you know all the ins and outs of these great cars? You simply amaze me with your breadth of knowledge.
All the best,
