Jump to content

Recommended Posts

Posted

With the optional intrument cluster on my Cutlass, my oil pressure gauge has been running high over the last couple of weeks. On the city streets and highways, at normal running tempretures, I'll be at about 45psi @ 2700 RPMs. When I downshift and pass slower traffic, the gauge spikes to 80psi @ 5000 RPMs, which is the maximum and it looks like it want to go even further! Even at idle, it runs at about 30 - 35psi where I've been hearing a normal DOHC runs at 19 - 23psi? My car seems to be reading incorrectly for running 5w-30.

 

My question: would a faulty or dying oil pressure sending unit cause this phenomenon, or is the intrument panel seen to many laps around the block with 174K miles on it? Anyone had similar issues? Thanks!!!

 

- RedFox340

Posted

Worry not mate, all is well. Thats a normal thing to happen with age. The machanism just gets more sensitive over time thats all. I have the same problem with mine. Just worry if it drops to low, then you have a problem.

Cheers :peace: :cheers:

Posted

The gauge will also spike if the sender gets bad. If in doubt, replace the sender. It'll cost you $25 or something...and it's worth knowing the oil pressure.

 

Jason

Posted

Agreed, and thanks! Now can I run a 2.8L / 3.1 MPFI OPS unit from a Gen I W-Body or do I need a DOHC calibrated OPS? Are they the same part?

 

- RedFox340

Guest TurboSedan
Posted

you're going by the oil pressure gauge in the digital gauges cluster right? how do you know what the oil pressure is actually at? mine isn't labeled at all. what is the oil pressure supposed to be when the gauge reads quarter,half, and 3/4 of the way up? usually on the highway mine reads 9-12 bars, in traffic it fluctuates from 5 bars (idleing in traffic) to 10 bars.

joshua

Posted
you're going by the oil pressure gauge in the digital gauges cluster right?

 

Nope... the upgraded analog gauges. :D The needle used to sit right about the 20psi mark and now will spike to 80psi and then some.

 

gauges.jpg

 

- RedFox340

Guest TurboSedan
Posted

wow i guess that answers that question :) i would relace the oil pressure sending unit and see what happens. could be a possible short in the wiring somewhere too.

joshua

Posted
you're going by the oil pressure gauge in the digital gauges cluster right? how do you know what the oil pressure is actually at? mine isn't labeled at all. what is the oil pressure supposed to be when the gauge reads quarter,half, and 3/4 of the way up? usually on the highway mine reads 9-12 bars, in traffic it fluctuates from 5 bars (idleing in traffic) to 10 bars.

joshua

 

To clarify things, the digital gages display the same thing as other w-body clusters IE the midpoint of the pressure gage is 40psi, max is 80psi, sucks that they didnt label the markings, but hey at least we don't have to worry about mechanical parts wearing out and accuracy loss...so it's a catch 22 :?

Posted

Had to use two different size sending unit sockets on my '88 2.8, one for the original, another for the replacement. The sending unit on my was next to the starter (+) terminal; disconnected battery terminal to avoid shorting out with socket. Also had to bend the A/C line to get the socket on the sending unit.

Posted
wow i guess that answers that question :) i would relace the oil pressure sending unit and see what happens. could be a possible short in the wiring somewhere too.

 

Ok, here's the deal after doing some book reading and cold calling dealerships... the 3.1L MPFI and the 3.4L DOHC are the same but there's some circumstances. First, the donor 3.1L MPFI cannot have the RPO option KC4 (engine oil cooling system) and the sensor is parallel to the oil filter just like the DOHC. It's a GM #12555492 and about 3.25" long with a three wire plug connected to it. The RPO option KC4 installed 3.1L MPFI's take a GM #25037205 and it's about 2.5" long and installs on the side (not parallel to the oil filter) of the oil filter spindle so that the external cooler can be hooked up. Thought I'd spread the joy and enlightment! :-D Now, all I have to do is replace the bastard over spring break... keep you all posted.

 

- RedFox340

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...