Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: tomuxzz on 12 May 2025, 16:15:27
-
Hi,
I have situation when Engine is hot. After driving some time. I think Engingine RPM drops too low (About 500) when it gets to 500 sometimes I got oil presure lamp. If I turn on AC for example. Engine RPM Jumps to 590rpm +- and Oil presure lamp turns off :D I added video. (in that video I accelerate a litle bit, after some time I realesed accelerator).
Maybe someone could advise me were to start check search problem ? look for a vacuum leak Or should I take on a more serious project and try to restore my old oil pump from another engine and replace it?
For now I dont have check engine error.
I changed origanal Cadilac Oil sensor to calibra oil presure sensor, because its impossible to find Cadilac senor.
I changed oil to 5w40
And I'm thinking maybe try to change spark plugs.
https://www.youtube.com/watch?app=desktop&si=-KBjnXvj_qddbOfF&v=baX2EZN64IE&feature=youtu.be&cbrd=1&ab_channel=Tomas
-
how many miles/kilometres are on the car? Low oil pressure at idle can be due to worn main & big end bearings ... :-\
-
It shouldn't be idling at 500rpm, though.
-
how many miles/kilometres are on the car? Low oil pressure at idle can be due to worn main & big end bearings ... :-\
139 000km
-
It shouldn't be idling at 500rpm, though.
I think same, and I dont know where to start look problem
-
And oil presure is always minimum on lowest white bar.
(https://i.ibb.co/FkcnvsZX/IMG-5927.jpg) (https://ibb.co/WN7s9D80)
-
how many miles/kilometres are on the car? Low oil pressure at idle can be due to worn main & big end bearings ... :-\
but I have this problem only on hot engine, and after driving some time.
-
It might be covered in the owners manual.
Basically it can be considered normal, especially on an older engine with some hours/miles on it.
However oil gets thinner as it gets hotter, so if your oil pressure is low when the engine is fully warmed up, then there's a chance you're using the wrong oil.
Equally, if the oil pressure doesn't increase with rpm then you need to prioritise removing the sump and checking the pick up. If it's blocked, you've found the problem, but if it isn't then the pump itself could be failing.
The idle speed is non adjustable on the 3.2/2.6/2.2 but 550rpm rings a bell as being normal.
-
It might be covered in the owners manual.
Basically it can be considered normal, especially on an older engine with some hours/miles on it.
However oil gets thinner as it gets hotter, so if your oil pressure is low when the engine is fully warmed up, then there's a chance you're using the wrong oil.
Equally, if the oil pressure doesn't increase with rpm then you need to prioritise removing the sump and checking the pick up. If it's blocked, you've found the problem, but if it isn't then the pump itself could be failing.
The idle speed is non adjustable on the 3.2/2.6/2.2 but 550rpm rings a bell as being normal.
Oil presure increases with rpm, for me looks like normal.
-
If you're using 5W30 switch to 10w40 and see if the hot idle pressure increases :y
-
If you're using 5W30 switch to 10w40 and see if the hot idle pressure increases :y
I tried this weekend, increased a little bit, but its still little bit missing when engine is hot. Now its enough just to turn on AC to reach minimim stock oil pressure norm on iddle. (when rpm is 550-600 its ok) but when 500 sometimes I get that damn lamp :D
I'm thinking to remove sump now..
-
Might also be worth checking the oil pressure relief valve while you're at it, although I can't remember where they are on this engine.
Blocked oil pickup is definitely a possibility and worth eliminating.
Could just be a lazy oil pressure switch?
If the oil pressure picks up quickly at higher revs it's possibly not work worrying about if the above check out OK.
It's normal for some variants of the V6 to idle as low as 450-500 RPM from memory.
-
I wouldn't be making any drastic decisions without actually measuring the pressure.
-
and as regards the idle speed its controlled via the air valveon the side of the plenum. if you squeeze the rubber hose from it the ecu should try to compensate by opening the valve more which will be obvious when you let go of the hose . if this isnt happening its likely the valve needs cleaning (or replacing).
-
and as regards the idle speed its controlled via the air valveon the side of the plenum. if you squeeze the rubber hose from it the ecu should try to compensate by opening the valve more which will be obvious when you let go of the hose . if this isnt happening its likely the valve needs cleaning (or replacing).
If it's a post 2000 Catera it is DBW... Basically a 3.0 block running 3.2.management
-
Might also be worth checking the oil pressure relief valve while you're at it, although I can't remember where they are on this engine.
Blocked oil pickup is definitely a possibility and worth eliminating.
Could just be a lazy oil pressure switch?
If the oil pressure picks up quickly at higher revs it's possibly not work worrying about if the above check out OK.
It's normal for some variants of the V6 to idle as low as 450-500 RPM from memory.
Maybe, plus I changed to not to same switch. Stock switch is this :
https://www.gmpartsgiant.com/parts/gm-sensor-90566938.html
Buts impossible to buy this part so I changed to this:
https://www.gmpartsgiant.com/parts/gm-sensor-90337695.html
Later I will try to make video with acceleration at idle.
-
3.0l idle is 450rpm with A/C off and around 550rpm with AC on.
-
Might also be worth checking the oil pressure relief valve while you're at it, although I can't remember where they are on this engine.
Blocked oil pickup is definitely a possibility and worth eliminating.
Could just be a lazy oil pressure switch?
If the oil pressure picks up quickly at higher revs it's possibly not work worrying about if the above check out OK.
It's normal for some variants of the V6 to idle as low as 450-500 RPM from memory.
Maybe, plus I changed to not to same switch. Stock switch is this :
https://www.gmpartsgiant.com/parts/gm-sensor-90566938.html
Buts impossible to buy this part so I changed to this:
https://www.gmpartsgiant.com/parts/gm-sensor-90337695.html
Later I will try to make video with acceleration at idle.
Something to consider, not all EPCs show the subsequent parts, and not all parts sellers have the presence of mind or ability/inclination to look beyond the "Discontinued" label. Leaving you to guess what the replacement might actually be.
Refit the original sensor and report back. No change means your old sensor is working normally.
-
Might also be worth checking the oil pressure relief valve while you're at it, although I can't remember where they are on this engine.
Blocked oil pickup is definitely a possibility and worth eliminating.
Could just be a lazy oil pressure switch?
If the oil pressure picks up quickly at higher revs it's possibly not work worrying about if the above check out OK.
It's normal for some variants of the V6 to idle as low as 450-500 RPM from memory.
Maybe, plus I changed to not to same switch. Stock switch is this :
https://www.gmpartsgiant.com/parts/gm-sensor-90566938.html
Buts impossible to buy this part so I changed to this:
https://www.gmpartsgiant.com/parts/gm-sensor-90337695.html
Later I will try to make video with acceleration at idle.
Something to consider, not all EPCs show the subsequent parts, and not all parts sellers have the presence of mind or ability/inclination to look beyond the "Discontinued" label. Leaving you to guess what the replacement might actually be.
Refit the original sensor and report back. No change means your old sensor is working normally.
Old original sensor Shows iol presure when engine is off.
Few times I got that red lamp with old sensor, thats why a started whole process from that sensor.
-
Hot engine:
https://www.youtube.com/watch?app=desktop&si=S-LQuYNT4yzQ6apZ&v=jHf-5uTrRj4&feature=youtu.be&cbrd=1&ab_channel=Tomas
Cold start:
https://www.youtube.com/watch?v=K2d5CzxY--E&ab_channel=Tomas
-
That the light is on tells you there's an issue.
Weak pump, or wrong viscosity oil. You may also want to check that the engine number matches the Car Pass/VIN data to confirm that the engine hasn't been replaced with a potentially much higher mileage one than the odometer might suggest.
-
Hot engine:
https://www.youtube.com/watch?app=desktop&si=S-LQuYNT4yzQ6apZ&v=jHf-5uTrRj4&feature=youtu.be&cbrd=1&ab_channel=Tomas
Cold start:
https://www.youtube.com/watch?v=K2d5CzxY--E&ab_channel=Tomas
Looks to me like the light is telling you the pressure is low but the gauge is behaving normally. I would follow Nick W's suggestion, get a workshop pressure gauge and actually measure the oil pressure before going too much further.
-
That the light is on tells you there's an issue.
Weak pump, or wrong viscosity oil. You may also want to check that the engine number matches the Car Pass/VIN data to confirm that the engine hasn't been replaced with a potentially much higher mileage one than the odometer might suggest.
There are plenty of other causes of the issue:
low oil level, wrong oil grade, worn component(these three are the most likely given the described symptoms), faulty switch(remember it's on/off), damaged wiring at the switch and others.
If the oil grade and level are correct(there's no reason to use anything other than 10w40 on a used engine), and the light goes out as soon as the revs rise off idle, then I would suggest there's nothing to worry about - this is how millions of engine have been used for decades
-
That the light comes on when decelerating, was what I should have typed.
I did wonder about the level... although the pressure switch is on the front of the block so deceleration should have the opposite effect... Which leaves the pump from the three primary culprits.
-
On a side note, that car makes alot of really annoying noises before it's running :-\
-
That the light comes on when decelerating, was what I should have typed.
I did wonder about the level... although the pressure switch is on the front of the block so deceleration should have the opposite effect... Which leaves the pump from the three primary culprits.
It doesn't matter where the pressure switch is, the oil pressure is almost constant everywhere downstream of the pump, but the location of the oil pickup pipe in the sump, and any baffles, etc. might do.
-
That the light is on tells you there's an issue.
Weak pump, or wrong viscosity oil. You may also want to check that the engine number matches the Car Pass/VIN data to confirm that the engine hasn't been replaced with a potentially much higher mileage one than the odometer might suggest.
There are plenty of other causes of the issue:
low oil level, wrong oil grade, worn component(these three are the most likely given the described symptoms), faulty switch(remember it's on/off), damaged wiring at the switch and others.
If the oil grade and level are correct(there's no reason to use anything other than 10w40 on a used engine), and the light goes out as soon as the revs rise off idle, then I would suggest there's nothing to worry about - this is how millions of engine have been used for decades
Good,
And thanks for all replies :) Today I removed little sump. I didn't find any metal crumbs inside. So now I decided to use engine like it is.If the oil pressure drops even more, only then we will try to restore the oil pump (I have another not working engine which ended because there was no oil presure :D ) . Because removing for now it is too much work.
this what i found. looks good.
(https://i.ibb.co/R44TnxvW/IMG-5966.jpg) (https://ibb.co/S77wThsp)
(https://i.ibb.co/SwjnvTbB/IMG-5965.jpg) (https://ibb.co/nMGck29j)
-
Finaly I've found info about those oil pumps here:
https://www.drive2.ru/l/506958699240096649/
Try to use google translate :) I think I will use this modification.
-
does look good yes . my pick up pipe was almost fully bunged up !
i renember replacing the o ring at the other end of the pick up pipe too .