Low Oil Pressure A4 30tdi MHEV

[JOCL0906]

Hello all,

Looking for some help/advice please?

So I bought this car May 24 with 90k miles full audi service history. I'm a private hire driver and its now on 166k no issues apart from common Adblue fault which has been mapped out and replaced a clogged EGR valve. My problem is low oil pressure warning has been coming on consistently for a while now. I've had an oil change and oil filter, new oil pressure sensor, oil pressure regulator all to no avail still getting the fault code. I know your not supposed to drive it all with this warning unfortunately that is not possible in my job? There are no obvious signs of anything majorly wrong, overheating, knocking noises, burning smells. The fault seems to trigger when the car is at temperature 90 - 100°c but is completely random after that. My mechanic is going to check the pressure with a mechanical gauge to see what is going on before I shell out for a new oil pump when it might not need one?

This has been going on for weeks now and is driving me mad.

Any help or advice would be greatly appreciated.

Thanks

Chris

 

[NHN]

Need to do some logging whilst driving to monitor the pressure readings.

 

[Darren92]

disappointing to see the parts cannon being fired before actually confirming they were at fault (clearly not as the problem didn't go away), poor show from your mechanic imo

 

[JOCL0906]

disappointing to see the parts cannon being fired before actually confirming they were at fault (clearly not as the problem didn't go away), poor show from your mechanic imo

I understand what your saying about the parts but what else can you do? The fault code tells you there is low oil pressure but not what is causing it? So apart from working you way through the most likely things to be at fault, how are you supposed to know?
He is fitting a pressure gauge on Monday and then hopefully we can see if the oil pressure is low, however if it is again what is causing it to be low and if the pressure is fine again what is causing it? What is the correct oil pressure?

Thanks

Chris

 

[spartacus68]

Needs live data on VCDS, that will show oil temperature, pressure. When the car was scanned - what DTCs were logged?

 

[JOCL0906]

Needs live data on VCDS, that will show oil temperature, pressure. When the car was scanned - what DTCs were logged?

Sorry, what are DTCs?

 

[B7Tourer]

I understand what your saying about the parts but what else can you do? The fault code tells you there is low oil pressure but not what is causing it? So apart from working you way through the most likely things to be at fault, how are you supposed to know?

I dunno... assume it actually really has low oil pressure? Especially since you changed the sensor and regulator. You're driving around professionally with a car that could be grenaded at any moment. The overwhelming likely cause with these B9 engines... which you didn't specify... but I can obviously assume is a diesel, is a clogged oil strainer. Difficult obviously to be definite as an armchair internet reply, but if it was my car and job, I wouldn't be wasting time checking oil pressure next with your mechanic - I would be having the sump dropped pronto and checking that strainer.

 

[JOCL0906]

Sorry, what are DTCs?

DTC's in attached file, thanks.

I dunno... assume it actually really has low oil pressure? Especially since you changed the sensor and regulator. You're driving around professionally with a car that could be grenaded at any moment. The overwhelming likely cause with these B9 engines... which you didn't specify... but I can obviously assume is a diesel, is a clogged oil strainer. Difficult obviously to be definite as an armchair internet reply, but if it was my car and job, I wouldn't be wasting time checking oil pressure next with your mechanic - I would be having the sump dropped pronto and checking that strainer.

Yeah it is a diesel and we have already dropped the sump and cleaned it all, new gasket and oil strainer/pickup was fine??? Yes I'm so worried that my car is going to blow itself to pieces at any moment although nothing unusual is happening and I've easily done over 2000 miles with this issue now??

 

[B7Tourer]

Yeah it is a diesel and we have already dropped the sump and cleaned it all, new gasket and oil strainer/pickup was fine???

You didn't mention that before... did you check the oil pump condition at the same time? It's best to provide as much detail up front as you can for the quickest help; or best of all go to Audi/or an independent specialist for a second opinion. What oil are you using, correct 5w30? Are you using a lot of it bewteen services? How often have you been changing it? For this kind of work you want to be cutting manufacturer's schedules at least in half, you've already put 76K in a year and a half, so 50K a year. As I say, if it was mine and my job I'd first assume it really has low oil pressure, not faulty sensors. Beyond that forums are not the best for this kind of thing, even with the best brains at it; no one can truly diagnose this remotely.

Chris, I've kind of been in your line of work before, here's what I would do: as you said a low oil pressure warning normally means, stop right now, since catsrophic damage can be a matter of seconds; flatbed straight to the garage. I would leave it with a competent mechanic; hire another car for work; let them get to the bottom of it. My own old B7 2.0 TDI diesel was infamous for oil pump failure, so I preventatively had it upgraded before any issues, now on 276K. I no longer chaufeur but I use that car day in day out for work and it's never let me down. I would not drive yards with a low oil pressure sign on in any car. Good luck!

Yeah it is a diesel

Low Oil Pressure A4 30tdi MHEV​

You did specify in the title thread too.... apologies for that.

 

[JOCL0906]

You didn't mention that before... did you check the oil pump condition at the same time? It's best to provide as much detail up front as you can for the quickest help; or best of all go to Audi/or an independent specialist for a second opinion. What oil are you using, correct 5w30? Are you using a lot of it bewteen services? How often have you been changing it? For this kind of work you want to be cutting manufacturer's schedules at least in half, you've already put 76K in a year and a half, so 50K a year. As I say, if it was mine and my job I'd first assume it really has low oil pressure, not faulty sensors. Beyond that forums are not the best for this kind of thing, even with the best brains at it; no one can truly diagnose this remotely.

Chris, I've kind of been in your line of work before, here's what I would do: as you said a low oil pressure warning normally means, stop right now, since catsrophic damage can be a matter of seconds; flatbed straight to the garage. I would leave it with a competent mechanic; hire another car for work; let them get to the bottom of it. My own old B7 2.0 TDI diesel was infamous for oil pump failure, so I preventatively had it upgraded before any issues, now on 276K. I no longer chaufeur but I use that car day in day out for work and it's never let me down. I would not drive yards with a low oil pressure sign on in any car. Good luck!


You did specify in the title thread too.... apologies for that.

Sorry I thought I had said the sump had been off and cleaned. New gasket, oil strainer/pickup. Sorry. No I don't think the oil pump condition has been checked. I have stuck to the manufacturer schedule which is every 9k miles. The oil is supposed to be 0w20 which is what has always been used, assume this is thin oil for stop/start engines? However due to the mileage and this problem my mechanic has tried 5w40 which is obviously thicker oil?

I understand what your saying to assume it does have low pressure and not drive it but as I've already said probably done around 2k miles now so will this mean the engine has suffered significant damage? Hiring a vehicle is not an option for private hire work due to licensing regulations.

Thanks

 

[B7Tourer]

The oil is supposed to be 0w20 which is what has always been used, assume this is thin oil for stop/start engines? However due to the mileage and this problem my mechanic has tried 5w40 which is obviously thicker oil?

You should deactivate stop/start every trip right away. That's for emissions not for engine life. 5w40 is a no no for DPFs. 5w30 507 spec is the only alternative - 0w20 is very thin; but your issue is immediate in the 'last 2000 miles'. I understand about hiring another vehicle - I was private in another country; but you're dicing and your mechanic doesn't seem to know what to do.

 

[spartacus68]

DTC: Diagnostic trouble code.

Only had a low oil pressure fault once in 30 years of owning Audis. That was on a 2001 V6 B5 2.5TDI Quattro Avant. Scared the hell out of me. Trouble was it was early in the morning and I was towing a boat at the time. No previous errors, and when the car was switched off and on again, the error didn’t reoccur. I checked oil level and looked at the camshaft with cap off. Possibly a calculated gamble on my part, but I put it down to a faulty sensor and had my day fishing. That car had oil changes religiously every 10k miles. I changed the sensor the following week. I sold it at 175k.

This car is your daily workhorse, 2.0TDI, and on 166k miles and Euro 6 with AdBlue mapped out. I’d be inclined to take it off the road until you’ve worked out exactly what’s going on with it. For example a compression test will tell you about the overall condition of the engine.

Diesels don’t like short run journeys, and if it’s a taxi, then you can expect the EGR valve to clog as a matter of course. On my old B5 the air intake manifold had a lot of carbon build up, including at the exhaust elbow. I stripped the whole lot down.

With VCDS you can run measuring blocks in a controlled environment, seeing oil temperature and oil pressure, going through the gears and rev range. Before starting I’d clear any historical faults.

Not sure how many oil pressure sensors are on B9, but personally I’d renew them for genuine VAG, not pattern parts. Renew oil and filter. 5w30 LL is what I use.

 

[JOCL0906]

DTC: Diagnostic trouble code.

Only had a low oil pressure fault once in 30 years of owning Audis. That was on a 2001 V6 B5 2.5TDI Quattro Avant. Scared the hell out of me. Trouble was it was early in the morning and I was towing a boat at the time. No previous errors, and when the car was switched off and on again, the error didn’t reoccur. I checked oil level and looked at the camshaft with cap off. Possibly a calculated gamble on my part, but I put it down to a faulty sensor and had my day fishing. That car had oil changes religiously every 10k miles. I changed the sensor the following week. I sold it at 175k.

This car is your daily workhorse, 2.0TDI, and on 166k miles and Euro 6 with AdBlue mapped out. I’d be inclined to take it off the road until you’ve worked out exactly what’s going on with it. For example a compression test will tell you about the overall condition of the engine.

Diesels don’t like short run journeys, and if it’s a taxi, then you can expect the EGR valve to clog as a matter of course. On my old B5 the air intake manifold had a lot of carbon build up, including at the exhaust elbow. I stripped the whole lot down.

With VCDS you can run measuring blocks in a controlled environment, seeing oil temperature and oil pressure, going through the gears and rev range. Before starting I’d clear any historical faults.

Not sure how many oil pressure sensors are on B9, but personally I’d renew them for genuine VAG, not pattern parts. Renew oil and filter. 5w30 LL is what I use.

Yeah it is my daily workhorse and has been perfect until now and serviced regularly with oil changes at the correct intervals with VAG parts. I had a 2016 A4 (B8 I think) previously and did exactly the same with regards to services and oil changes sold that car with 250k miles on it and never had any of these problems. Only thing I had to do was replace the entire front suspension due to the shocking state of our roads!
Yes I know diesels don't like short journeys but the work I do includes a lot of airport runs so probably 50/50 short trips and long trips.
Already replaced the EGR valve as it was getting clogged.
I'm taking it off the road for as long as I can afford to find out what is going on.

Thanks

 

[JOCL0906]

So it looks like it was actually an issue with the DPF!! Occasionally it was giving the fault code P2002 DPF filter (bank1) is not working efficiently! Apparently the car will add extra fuel to raise the exhaust temperatures if the DPF is not working properly and regeneration isn't clearing all the crap out and some of the fuel can end up in the oil and dilute it too much triggering the low oil pressure!!! Its all been cleaned out and have done over 400miles since trouble free and no fault codes. So its all this euro emissions crap that tries to kill your engine!!!! Hopefully it's sorted now anyway . Thank you all for the advice and help, very much appreciated!

 

[spartacus68]

Good news. Glad you got it fixed.