: Oil pressure



STSj90
03-27-09, 05:29 AM
Ive been wondering why cadillac didnt put an oil pressure gauge in these cars? Only thing they have is the ''dummy light''..And once you see that. You better pray! Is there a way to go into the computer and check the oil pressure just like i can check the trans oil temp and IAT?

Or if i want that kind of convenience would i have to hook up an oil pressure gauge to my car? Im always wondering what my oil pressure is. And worrying.. It would be nice to see...

Submariner409
03-27-09, 10:14 AM
GM's spec for the Northstar is 5 psi minimum at idle, 40 psi+ at 2000 rpm. I do not believe that the oil pressure sending switch is an actual variable resistor which would supply gauge readings. It is an on/off switch, set to about 6 psi, so it will only turn the indicator icon on and off. Some Cadillacs have had flickering oil lights at idle when hot in traffic and a sending switch replacement cures the problem most of the time.

In order to install a gauge, either mechanical or electrical, you need to use a T fitting on the oil filter adapter/pressure switch tap. The pressure switch goes in one leg of the T, the new sending unit/capillary tube fitting in the other. Not a difficult install, just time-consuming and a bit tight to work on. Nowadays, most "oil pressure gauges" are so highly damped that, once the engine starts, the needle never moves. The reason ?? Today's drivers go freako if a gauge moves: having been brought up on idiot lights, they don't realize that a normal engine will vary oil pressure by over 40 psi, temperature by 50 degrees, voltage by 5.5 volts, and amperage by over 60 amps, all the time. The phony gauges installed in cars prevent a lot of useless service calls.

GM likes to run their engines at 40 -45 psi hot, highway, while Ford is about 10 pounds higher.

STSj90
03-27-09, 08:15 PM
I understand oil pressure is all over the place depending on engine temp,and rpm. I will work on installing an oil pressure gauge in my car. Im tired of wondering what my oil pressure is and just waiting for bad engine noises to tell me my oil pressure is low.


Ill post up on the progress. What T fitting do i need? Or will i have to just do some ''fitting'' and testing myself?


Thanks for posting up sub.

32vmonte
03-27-09, 11:11 PM
I understand oil pressure is all over the place depending on engine temp,and rpm. I will work on installing an oil pressure gauge in my car. Im tired of wondering what my oil pressure is and just waiting for bad engine noises to tell me my oil pressure is low.


Ill post up on the progress. What T fitting do i need? Or will i have to just do some ''fitting'' and testing myself?


Thanks for posting up sub.

I believe the T fitting comes with the oil press. gauge. What it is when you go to the autoparts store you usually get everything you need with the gauge, it will have a little hose and some fittings, I think most oil pressure sending units are the same thread, I noticed atleast on GM vehicles.

What you do is take the oil press. sending unit off I believe and the T fitting installs where the unit was. You then install the unit onto the other side of the T fitting. You now have tapped into your oil pressure to feed a reading to your gauge.

I may be wrong but this is what I gathered from looking at one and asking someone where it goes and thats what they told me.

Someone will correct me if it is needed.


This is what it would look like......but with a different feed line.

http://www56.homepage.villanova.edu/daniel.arnal/images/wrx/pics/img_1740.jpg


Or you can get one that has a electronic sending unit which avoids running lines with oil in them around your car. Like this

http://www.miracerros.com/mustang/gauge_ATM_3327.jpg


Here is the electronic one installed in a similar fashion as you would.


http://wiki.seloc.org/images/8/85/Oil_Pressure_Transducer_Connected.JPG

STSj90
03-28-09, 12:35 AM
Thanks a bunch man! Good info! Im going to get an electonic one. To avoid running oil lines....

By the way, One of your pics dont work.

32vmonte
03-28-09, 12:55 AM
yea no problem, weird the pictures aren't there. Oh well you get the idea pictures or not.

I would defiantly go with the electronic one its a no brainer. I seen some for 50 bucks I think from autometer. Not a bad price.

STSj90
03-28-09, 12:57 AM
Yea, im going with elec....


And its just one of your pics that dont work. The middle one. The other 2 pics work fine for me.

Thanks

Ranger
03-28-09, 01:05 AM
I understand oil pressure is all over the place depending on engine temp,and rpm. I will work on installing an oil pressure gauge in my car. Im tired of wondering what my oil pressure is and just waiting for bad engine noises to tell me my oil pressure is low.


Ill post up on the progress. What T fitting do i need? Or will i have to just do some ''fitting'' and testing myself?


Thanks for posting up sub.
I'm not trying to talk you out of this so install one if it makes you feel better , but you are obsessing WAY too much over this. I can't ever recall of anyone having an oil pressure problem unless they took the engine apart and failed to torque the harmonic balancer down enough.