View Full Version : Oil Pressure Light + Warning

05-17-10, 05:45 PM
So coming to work today I got to sit in lovely traffic for almost an hour. About 20 minutes in I noticed the pressure light start blinking as the car would roll to a stop, stopping making the light stay on. Figured it was the switch because it has happened before and there was nothing to worry about. About another 20 minutes in I start getting warnings to stop the engine every time I stop.

To get through traffic I have to have the RPMS a little below 1000 and everything goes away. The only thing that has me worried is with the constant low pressure light as well as the warning the temp started to rise.

After I was through traffic I gunned it to my usual cruising speed and I watched the temp drop as well no more indicator lights. When I came close to work and started to hit stop and go traffic again I did not receive any lights or any warnings of low pressure, and after searching through these forums I somewhat believe it may just be a switch, because with the lack of oil pumps that go bad it is not likely it is that. But just because not a lot of people report them doesn't mean it doesn't happen.

I was wondering if anyone had any symptoms like mine, where the temp actually did rise. Also, any thoughts or insight is appreciated.

Should add as well, she is a 99 deville concours


05-17-10, 06:19 PM
"Temp started to rise" - to what value ? Click on the pic to enlarge.

Check the cooling fan fuses and relays in the underhood fuse box. You may have a fuse box in which there are other maxi-fuses in the box behind the primary box.

It's possible that the oil got a bit warmer than usual what with the stop & go traffic, and as you said, the sending unit has given you warnings before.

If possible, get the car up on a hoist, pull the right front wheel and fenderwell liner. Remove the lower transmission inspection plate and have a assistant lock the flexplate ring gear with some sort of tool in the teeth. Now try to torque the harmonic balancer bolt to 260+ ft/lb : the oil pump is wrapped around the crankshaft snout and is driven by friction between the balancer hub and the pump drive sleeve. You would not be the first to discover a (relatively) loose crank hub bolt.

05-17-10, 07:05 PM
"Temp started to rise" - to what value ? Click on the pic to enlarge.
I noticed it at 225. From the stop and go I didn't let it continue before I stepped on the gas a tad, but it appeared that it would shoot up a snitch, then slowed down as it neared 225.

I will check the fuses tomorrow I am hoping. I will note as well, nothing odd sounding from the engine. The only noise that can sometimes be heard is my dead AC compressor kicking in and trying to work. (incase that may have any relation) But that has been non functioning for 2 years now.

I will have a mechanic take a look at the bolt as I do not have the tools. Hopefully they will resolve the issue if there happens to be one there.

A question on changing the sensor as well: When I tried it last year I was able to get to the sensor (what I thought was the sensor) but there was a bar blocking it. This was a year ago so it is a tad fuzzy, but I do remember the filter and a bar or a beam in the way and I was not able to remove it. Any suggestions or ideas? Or was I trying to remove something completely different?

05-17-10, 10:42 PM
The temperature rise in traffic: I assume that the A/C was OFF or dead - in which case fans go to SLOW at 225 and FAST at 236. If fans go to SLOW at 225, the coolant goes down to ~213 and fans turn OFF. The cycle repeats. Perfectly design normal. (Fix the A/C - you'll go paranoid this summer with temp spikes: If the A/C is commanded ON and is working, fans run in SLOW all the time, so the gauge sits at 12:00 or so - period.)

oil pressure sensor...............PITA

05-19-10, 07:05 PM
oil pressure sensor...............PITA

You're telling me. A couple of things I found out the last day or two. I added a tad bit of oil and it seemed to make her run a bit better. I have not checked my reciepts but I have had issues with the oil change place not adding 7 quarts in, only 5. I don't get charged for 7, that is usually how I can tell. But adding to that the engine does burn a snitch of oil, which from the sounds of it is normal. With a full 7 quarts I never receive the warning light, but even a bit less it will come on. So I added some and now no more light.

Besides that I am starting to think my car is haunted and this is its way of getting back for not driving her for a weekend.

To add on, the only reason the temp rising worries me is because the temp never rose above the center. No matter what the load was. But I guess that is just what age can do to a vehicle... She will never be like she was 3 years and 15k miles ago.

05-19-10, 11:00 PM
Never trust any oil change quickie shop to correctly fill a Northstar !!!

The proper fill, with filter, is 7.5 quarts. This should bring the level on the dipstick to just about halfway up the hashmark - between ADD and FULL. Never maintain the level at FULL - that's a half quart overfilled and is the subject of a GM/Cadillac TSB concerning perceived oil consumption. Check oil level after at least a 5 minute draindown period on a level surface. Any other check is wrong. If you check oil level COLD it will be a tad less than if checked WARM. Resist the temptation to "top it up".