too much oil and oil pressure....

[wwdwgs]

Hello, guys.
I wonder, can overfilling an engine with oil (about 1/8" above high mark on dipstick) cause oil pressure to stay at 5 bar, even at idle. BTW - my idle is high - 1000 rpms.
Another possible cause - replacing front end seals and seals inside Oil-Coolant radiator. I used a tool (inserted instead of pressure valve) to align it upon installation.
Before these repairs oil pressure was staying between 2.5-3 at idle and reached 5 on acceleration.
I need your input.
Thanks.

[pfarah]

It sounds like you may have reversed the oil sender wires.

Just my humble opinion: One should always use the proper alignment tool when reinserting the oil pressure valve.

[walfreyydo]

+1 on reversed sender wires.

If thats not it, then your OPRV may be binding (although you said you used the alignment tool, so not sure how likely this is).

[wwdwgs]

Thanks, guys. I will switch the wires around and see what will happen next.
Honestly, I didn't mark those wires on disassembly.

[wwdwgs]

No. same effect - oil pressure shows 5 on warm idle. Doesn't even budge when I press gas pedal.
Before I connected ground wire to "G" terminal on an oil pressure sender.
Doesn't "G" in German means Ground? or, maybe, just German?
I'm puzzled.

[wwdwgs]

with two wires switched, as you suggested, my observations of oil pressure gauge:
ignition ON - needle jumps to 1-ish,
cranking - needle jerks to 3-ish
engine runs - needle stays just above 5.
hot idle - needle is just above 5
engine turned off - needle drops to 1 and slowly moves to 0.
So, what do you think, stuck oil pressure relieve valve in Oil-Coolant Radiator?
BTW - car is 87 924S and oil pressure valve is "an old style" - 3-piece.
I need to drink. Did I mentioned "Happy Friday"?

Other thoughts...
this issue appeared after I replaced front-end seals, oil/coolant radiator, toothed sleeve for oil pump (at crankshaft)...

Possible causes:
1 - improper installation - valve stuck (even with installation tool).
2 - improper installation of wires (ground wire was connected to G terminal). Switching wires didn't fix the issue.
3 - one terminal was twisted off (with spade connector) and was soldered on - possible thermal damage of internals??? (previous post - https://forums.pelicanparts.com/porsche-924-944-968-technical-forum/1113165-when-you-break-things.html)
4 - damaged valve (I don't see how, but...)
5 - damaged oil pressure sending unit because of switched wires (if that's the case).
6 - damaged oil pressure gauge.
7 - dirt got into small hole in oil pressure sending unit (I doubt, because it worked before)
8 - thicker oil than before - had 10W40 before, changed to 20w50
9 - too much oil?

Possible solutions:
1 - reinstall oil/coolant radiator. Or, at the lease, loosen it, remove valve, stick in alignment tool and re-tighten nuts/bolts.
2 - have no idea
3 - none
4 - get a new valve? Updated?
5 - clean the hole by submerging it in some solution like carb cleaner? Or buy a new one (Don't like an idea of buying (maybe unnecessary) new parts).
6 - none? I doubt that the gauge is damaged - the needle still moves.
7 - cleaning....
8 - drain oil and use lighter, like 10w40
9 - drain some oil....I really don't see how 5 or so extra ounces may have such an impact. Are German engines SO sensitive?

[wwdwgs]

Update:
Theoretically, I switched the wires and Blue/White must be connected to "G" terminal. I will re-solder the ends of wires and will check how oil pressure gauge behaves.

[walfreyydo]

Before going further, you may consider replacing the oil pressure sending unit just to be sure its good.

The only things that I know of that can cause high oil pressure is a stuck OPRV or incorrectly wired/faulty Oil Pressure Sender. I have heard that oil will spray out the seals around the oil filter when OPRV is stuck (as documented in other forum posts). If yours isnt doing this I would start with replacing the Oil Pressure Sending Unit.

They have made an update replacement for the "old style" OPRV (because they bind, even if installed correctly) - you may want to look into replacing your existing one (well documented on this blog post) - a possible solution to problem #1
https://944foot2thefloor.blogspot.com/2010/07/how-to-remove-and-replace-oprv-oil.html

http://www.clarks-garage.com/shop-manual/lube-02.htm
Oil Pressure General Information and Troubleshooting Tips.

[wwdwgs]

Oil Pressure Sending Unit...
There are few available from different manufacturers - Uro, Beck/Arnley, WVE and VDO. Pricewise, Beck/Arnley looks good with 3 year warranty. (VSO, btw, offers 2 year warranty). Wve - never heard of them. Uro - may not be a good choice as an electronic device.

Also, I was suggested to "manually test" Oil Pressure Valve by unscrewing it, but leaving floating piston inside and try to push and pull it with my finger (I wont' tell you exactly which finger).
If it's moves freely, then the problem is more likely with an Oil Pressure Sending Unit (OPSU).

walfreyydo,
I've read those posts some time ago, when I was about to work on Oil/Coolant Radiator.

[wwdwgs]

Update:
I unscrewed Oil Pressure Valve and felt piston movements - moves well without any binding.
This is a good news...

[walfreyydo]

One thing you could also try is to unscrew the Oil Pressure Sending Unit and screw on a mechanical oil pressure gauge to verify whether the sending unit is actually faulty or not.

[wwdwgs]

walfreyydo,
that would be nice, but I don't have any oil pressure gauge.

[wwdwgs]

update:
I replaced an old Oil pressure sender unit.
After first warm-up, the oil pressure was at 5, on acceleration - over 5.
after second warm-up - 4.5.
after short drive - 3.5.
oil used - 20w-50.

[walfreyydo]

Thats within spec, sounds like the sender was the issue. Thanks for reporting back, its always helpful for others

[wwdwgs]

Thank you all for your help.

[heliolps2]

Originally Posted by wwdwgs

Thank you all for your help.

Thank you for the updates, This type of info really helps us.