Oil Light Issues

[Smitty17]

I've been researching for hours so apologies if I've missed something obvious but here's the situation.

Changed oil a couple months back and like a week ago, my oil light came on. I freaked out, checked the oil, and to my surprise it was full. It was actually a bit too full so I got a small hose and sucked a bit out hoping maybe that'd fix it. Well it didn't. After some research, I decided to put a third of a can of seafoam in and drive it for about a hundred miles and do an oil change. I did that, changed it today and still the light comes on. Tends to happen at low rpm. If I'm on the highway for awhile, it shuts off. Yes, I realize I need to not be driving it. But it's my only means of transportation and I was just hoping I'd fixed it (both times) and now I'm thinking I'm going to have to start trying some bigger things.

I've read my engine is known for sludge issues and thus a lot of people point to the pickup screen. I've seen a couple of people point the the vacuum/pcv system as that somehow effects something that can make the light turn on?

So I don't know what I expect you to tell me that I probably haven't read. lol. But I guess I keep ending up on this forum and figured I may as well post and idk.. maybe somebody can help me. Really don't want to replace the pickup as it looks like a massive pita but that seems to be the most common culprit.

[Dr.B6Banter]

You probably already saw this thread regarding the 1.8t and potential issues relating to oil pressure.

There are 2 oil warnings that can appear. I believe an orange one relating to a low oil level and a red flashing one relating to low oil pressure. The operating oil pressure of the engine at idle is just a little higher than the pressure at which the low oil pressure switch activates so by design the ECU does not display any warning lights relating to oil pressure until the rpm is higher than 1600. the fact that your warning comes on at the lower rpms leads me to believe there is reduced oil flow and pressure due to a restriction in the oiling system (likely the pickup screen) meaning that your oil pressure is low enough to trip the pressure switch at say 2k rpm (21psi) when it should be above 40 psi.

The only really definitive way to rule out the pickup screen being clogged is to get a oil pressure gauge and hook it up on the block where the oil pressure switch is normally located to see what the oil pressure is at various rpms. A warm idle should be around 25 psi and should go up quite a bit as the rpm increases (mine peaks at about 60-70 psi closer to redline)

You probably don't want to hear this, but the fact that the oil pressure light goes off at highway rpm only means that oil pressure is above 21psi and does not mean that it is at the 40-50psi that it needs to be at to properly lubricate the rotating assembly.

Capture.jpg2k oil pressure.jpg

[EuroxS4]

You can try adding lucas oil stabilizer when you do an oil change. I have seen it resolve the oil pressure lights here and there. But ideally a oil pan drop and pickup tube replacement is the best course of action to resolve the issue. Are you sure its a oil pressure light and not a oil level sensor light?? Pressure is red,level sensor is yellow. Chances are you have lots of stuff stuck restricting the pick up tube. I have also seen guys put half a quart of diesel fuel into the crank case and run the engine for 5-10 minutes. But its not something I recommend as diesel fuel can swell seals and you can end up with a front and rear main seal leaking causing a bigger issue. Best of luck if it is pressure, pressure test is a good test to do however I will also mention this. The oil pressure switches on these cars love to piss oil right through the switch into the connector. Sometimes its just the switch that needs to be changed and nothing else. Please be sure to check this as well.

[Smitty17]

You probably already saw this thread regarding the 1.8t and potential issues relating to oil pressure.

There are 2 oil warnings that can appear. I believe an orange one relating to a low oil level and a red flashing one relating to low oil pressure. The operating oil pressure of the engine at idle is just a little higher than the pressure at which the low oil pressure switch activates so by design the ECU does not display any warning lights relating to oil pressure until the rpm is higher than 1600. the fact that your warning comes on at the lower rpms leads me to believe there is reduced oil flow and pressure due to a restriction in the oiling system (likely the pickup screen) meaning that your oil pressure is low enough to trip the pressure switch at say 2k rpm (21psi) when it should be above 40 psi.

The only really definitive way to rule out the pickup screen being clogged is to get a oil pressure gauge and hook it up on the block where the oil pressure switch is normally located to see what the oil pressure is at various rpms. A warm idle should be around 25 psi and should go up quite a bit as the rpm increases (mine peaks at about 60-70 psi closer to redline)

You probably don't want to hear this, but the fact that the oil pressure light goes off at highway rpm only means that oil pressure is above 21psi and does not mean that it is at the 40-50psi that it needs to be at to properly lubricate the rotating assembly.

Capture.jpg2k oil pressure.jpg

Appreciate you taking the time on that lengthy response! It is definitely the red oil light. I agree that it's likely the pickup but I'll see if I can get a pressure connector connect to verify

[Smitty17]

You can try adding lucas oil stabilizer when you do an oil change. I have seen it resolve the oil pressure lights here and there. But ideally a oil pan drop and pickup tube replacement is the best course of action to resolve the issue. Are you sure its a oil pressure light and not a oil level sensor light?? Pressure is red,level sensor is yellow. Chances are you have lots of stuff stuck restricting the pick up tube. I have also seen guys put half a quart of diesel fuel into the crank case and run the engine for 5-10 minutes. But its not something I recommend as diesel fuel can swell seals and you can end up with a front and rear main seal leaking causing a bigger issue. Best of luck if it is pressure, pressure test is a good test to do however I will also mention this. The oil pressure switches on these cars love to piss oil right through the switch into the connector. Sometimes its just the switch that needs to be changed and nothing else. Please be sure to check this as well.

Thanks for the response! I'll definitely check those things

[Dr.B6Banter]

Appreciate you taking the time on that lengthy response! It is definitely the red oil light. I agree that it's likely the pickup but I'll see if I can get a pressure connector connect to verify

No problem. I got the oil pressure tester in those photos off amazon for quite cheap. The reason I suggested it is because it's a much safer way to test oil pressures than going on a drive and waiting for the low-pressure light to come on, and as it is your daily having the motor lock up while on the highway can be quite a bad situation.

https://www.amazon.ca/gp/product/B07...?ie=UTF8&psc=1

Also, the pickup tube isn't far from the oil drain plug so you may be able to shine a light through the drain hole and use your phone to snap a picture of the pickup screen.

[Deerhurst]

You can try adding lucas oil stabilizer when you do an oil change. I have seen it resolve the oil pressure lights here and there. But ideally a oil pan drop and pickup tube replacement is the best course of action to resolve the issue. Are you sure its a oil pressure light and not a oil level sensor light?? Pressure is red,level sensor is yellow. Chances are you have lots of stuff stuck restricting the pick up tube. I have also seen guys put half a quart of diesel fuel into the crank case and run the engine for 5-10 minutes. But its not something I recommend as diesel fuel can swell seals and you can end up with a front and rear main seal leaking causing a bigger issue. Best of luck if it is pressure, pressure test is a good test to do however I will also mention this. The oil pressure switches on these cars love to piss oil right through the switch into the connector. Sometimes its just the switch that needs to be changed and nothing else. Please be sure to check this as well.

Putting a little ATF in the crank case is also a known method for breaking up the gunk. I've also been told to use Rislone.

[Kevin C]

If its like the carbonized oil that I have seen the little particles that tend to clog the pump input are quite tough and don't breakdown very easily but can be broken loose from the crankcase. Assuming its not the sensor I think the only real solution is to pull the pan, clean it and replace the pickup. A first step is to pull a cam cap and check for damage, that will tell you what the rest of the motor looks like. If its badly scored you have a bigger problem. Audi had a TSB about this.

More likely a solvent will just loosen up more particles that it cleans off of the inlet screen making the problem worse. I learned this the hard way on another make of of car way back when.

[EuroxS4]

I would also agree with Kevin. Pulling cam caps is also something to check,however I would check switch first to make sure its not pissing oil right through it. If not then Its a good idea to pull the cam caps. Normally either the front or the rears start to score first. If you have significant scoring its a good idea to pull and replace the head or look for donor engine.

Yes Audi had a TSB they also had a special engine flush machine with dedicated oil filter where the engine would run at 3k rpms for 20 minutes with special engine flush fluid from BG it would dissolve all the sludge in the engine. I have seen this save engines that sounded horrible. Other times it did not work out so well.

[shurur9]

I put mmo in just <1k before an OC.
Also have used Kreen twice in about 220k miles