Oil Pressure warning light

[richtung]

Hi Guys,

Just wanted to share my experience for the benefit of others.

Started the car one day last week, drove maybe 10 meters off my drive when i got the STOP! Oil pressure warning light. Got the car back on the drive.
Went to check oil level and as i pulled out the dipstick, bits of the plastic bead came out also. My immediate thought was that the plastic debris has been caught up in the oil pickup pipe strainer/filter. (oil level was fine)
Called AA out and the guy towed the car to my VW Indy. (i have garage cover as well as breakdown cover)

My garage got the claim authorised with the AA and the following was replaced:

New pickup pipe and O Ring
New Dipstick and Tube
New Sump plug
Sump sealant (proper VW stuff)
Fresh Oil
Oil Filter
Sump Plug

I only paid £35 excess - the AA paid the rest.

So pretty happy with that. Drove the 20 miles or so home, no issues.

Next day, come to start the car, drove 10 meters and the STOP!! Oil Pressure warning light comes back on (FFS).
Checked oil level and its fine. Called the garage and they said to get the car back in but couldn't take the car for a week as they were busy. Decided to wait a few days before calling the AA out to tow it to the garage.

Fast forward today. Had to push the car 1 meter to get into the garage. Car parked up but the gear selector stuck in "N". Found online that there is a locking mechanism that you need to push and move the selector. (car is DSG BTW) Done that, all sorted.
At this point, i had the key in the ignition and switched on (but not the engine). Suddenly, an "Airbag Fault" warning came on the dash. FFS i thought. I thought i messed up the wiring somewhere whilst messing with the gear selector. Then the dash went really dim and the interior lights started flickering.
My gut instinct is the battery is flat. So i go and get my Ctek charger and get it all hooked up - only that the charger wont let me charge the battery. This indicates the battery is properly goosed. So, i duly called the AA man out again.

He hooks up the battery tester and after 10 mins, the report comes back and confirms the battery is goosed. Good stuff - the AA garage cover includes batteries. AA man said he couldn't get me a Bosch S5, only the Bosch S4 (which he had in his struck). I would just pay £35 excess. Considering it was 9pm on Sunday, this was the best deal i was going to get by a long way. So i gave him the go ahead. New Battery fitted. I also got him to check for error codes - no errors found which was reassuring.
After the battery was fitted, the usual steering wheel lights came on but car started without issues. Paid him the £35 and sent him on his merry way.
Got in the car, started up and went for a short drive. Steering wheel light disappeared, airbag fault warning never came back and most importantly, the the oil pressure warning light never came back!  #

Although its been a roller coaster of emotions (mainly stress!), the car appears to be sorted. Perhaps the oil pressure warning was the dying battery all along but I'm not bothered, i've got a big chunk of preventative maintenance done for £35 and a brand new battery for another £35. Yes, i would have preferred a Bosch S5 (as thats what it had fitted) but for £35, im happy with the Bosch S4.

All worked out in the end!

Thanks for reading.

Rich

[Bens313]

Hi Rich, thanks for sharing! Out of interest how long have you been driving it now whilst it has been fine? Ive had alternators go in the past with similar weird warning lights and symptoms that kill the battery eventually. Im assuming youve been driving long enough to know its not that and your not going to drain the new battery? Might be worth running a multimeter over the battery when running just to check its charging fine if not.

Ben.

[richtung]

Hi Ben, thanks for your reply.

Ive only been driving it a day, seems ok to my untrained self. The old battery last just shy of 7 years so got my moneys worth.

Good shout on testing the alternator. i have a multimeter at home.

Would someone be kind enough to remind me, the mulitmeter just needs to be set to 20V DC and press the probes onto the corresponding battery terminal (negative first) whilst the engine is running? I believe anything over 14.3V means the alternator is healthy?

Cheers guys

Rich

[Bens313]

My Mrs old polo managed to do about 60 miles on a dead alternator just using the battery which was luckilly enough to get it to the garage.

Yes if you set it to DC it should read about that when running, normally around 12.6-12.8 ish when not running.

If everything seems well. Another usefull check you could do while your there if you have someone with you is to check how quickly the alternator gets up to that charging voltage after starting. It should be pretty much instantaneous. Had a friend that was chasing an electical issue around the engine bay for ages before realising the voltage would very slowly climb from off voltage to charging voltage which was apparently enough for the car to start throwing lights and the alternater was the culprit.

Hope its all good now though.

Ben.

[pudding]

The voltage may vary with temperature and whether the car has a parasitic draw, but generally, so long as you see 12.3V with the ignition on, that's fine.

Anywhere between 13.8 to 14.4V with the engine running is fine.

It's worth checking the state of the ground strap.  The main battery to body one, which is easy to see.  And there's one on the gearbox as well.  If you see any green crusties or rust on or around the body strap, I would take it off and sand it all back to bright metal.

[richtung]

Measured the voltage whilst the engine was off and got a reading of 12.65v which seems healthy (considering its a brand new battery).

Measured with the engine on and got a reading of 13.88v which I think is on the lower end of "healthy"?

Incidentally, with the engine only just switched off, I could hear a buzzing sound from the alternator. Don't know how long the buzzing sound went on for as I had to close the bonnet and get back into the house.
Is this buzzing sound normal? I don't recall hearing this before?

Cheers

Rich

[LC5F]

Measured with the engine on and got a reading of 13.88v which I think is on the lower end of "healthy"?

Incidentally, with the engine only just switched off, I could hear a buzzing sound from the alternator. Don't know how long the buzzing sound went on for as I had to close the bonnet and get back into the house.
Is this buzzing sound normal? I don't recall hearing this before?

The alternator adjusts output to optimise the battery voltage - so if the battery is low it should produce over 14V - your alternator sounds fine.

Buzzing sound - are you sure its the alternator? could be carbon canister

[richtung]

Just rechecked with multimeter - this time I remembered to switch off the headlights, interior lights, Aircon and blowers. This time I got a reading of 14.00v which seems more 'normal'. So can relax a little.

@LC5F it could possibly be the carbon canister as it's so close to the alternator.
Does the alternator usually make a buzzing immediately after switching the engine off?

Thanks.

[richtung]

So, the saga continues. Oil pressure warning came on again this morning.

I decided to keep on driving because:

A) I already had a new pickup pipe fitted a week ago so was reasonably happy the pickup pipe was not blocked
B) The AA patrol man who came to replace the battery told me that if there as a genuine issue with oil pressure, the car wouldn't sound right / engine would cut etc. He said it was fine to drive to the garage to get the oil pressure sensor changed as that was the usual culprit ( after blocked pickup pipe)
C) The car drove fine for 2 days without any warning lights after the battery had been changed
D) I was getting peed off with it

The car drove fine apart from the oil pressure warning popping up randomly.

I cant get it booked in the garage until next week but i think its looking more likely to be a faulty oil pressure sensor.

Does anyone have a rough idea on labour time and the actual of the sensor?

Thanks

[OllieVRS]

So, the saga continues. Oil pressure warning came on again this morning.

I decided to keep on driving because:

A) I already had a new pickup pipe fitted a week ago so was reasonably happy the pickup pipe was not blocked
B) The AA patrol man who came to replace the battery told me that if there as a genuine issue with oil pressure, the car wouldn't sound right / engine would cut etc. He said it was fine to drive to the garage to get the oil pressure sensor changed as that was the usual culprit ( after blocked pickup pipe)
C) The car drove fine for 2 days without any warning lights after the battery had been changed
D) I was getting peed off with it

The car drove fine apart from the oil pressure warning popping up randomly.

I cant get it booked in the garage until next week but i think its looking more likely to be a faulty oil pressure sensor.

Does anyone have a rough idea on labour time and the actual of the sensor?

Thanks

I'm afraid I don't know the labour but the first time I took my sensor out, it took 5 hours, as I had no idea what I was doing. Second time, 1.5 hours.

I'd say they would charge you for 2/3 hours of labour and £20 for a sensor (ask if they'll fit a genuine one).

As for the low oil pressure itself, it is strange that you got it straight after starting the car. That means you have either no oil pressure (oil pump not functioning at all) or the sensor is indeed faulty. You'd know as the engine sounds really rough without any oil pressure. On cold idle your oil pressure should be around 51-65psi, do trigger the sensor it would have to be below 17.4-23.2 psi.

When you got the low oil pressure, were there any strange sounds from engine, like metal rattling? Was there a burning smell?

Before getting the sensor replaced I would suggest asking them to measure the oil pressure first. I don't mean to scare you, but low oil pressure can cause serious damage, and is not to be messed with.

These are the specs you should be getting with the car fully warmed up. Anything lower, and you've got a serious problem.

[richtung]

Thanks for the reply @OllieVRS and all the info 

The warning didn't come on straight away after starting - it came on after driving maybe 10 meters.

No strange sounds or smells when the warning comes on either.

I'll get it booked in at my Indie again.

Thanks

[richtung]

Just a further update.

Got to the car this evening and checked oil levels - all good.
Started the car and drove home - no oil pressure warning light. Car drove fine.

So, it would appear the opening and closing the bonnet clears the error a few days. So in my case:
1) after the garage replaced oil pickup pipe
2) after the AA man replaced battery
3) after I checked oil level

If the same pattern is followed, the warning light will come back on in a couple of days.

Does anyone have any ideas?

It's booked into garage next week but keen to see what people's thoughts are?

Cheers Rich

[akbarirfan]

If your car signals that the oil is low, if there's no evidence of the bonnet being opened and closed, it will still say the oil is low even after topping up.

I know this as my bonnet electric cables got accidentally yanked off the latch.

[OllieVRS]

It's still unclear whether it's actually low oil pressure or an electrical issue, with the latter being much rarer.

I know you had loose pieces of plastic in your sump, but I'd ask your mechanic if he also saw any metal flakes/particles in the sump/oil. Another way you could check for them is by taking out the oil filter and checking there's no flakes/particles in it.

Mine only got low oil pressure after I'd driven for a while and then drove it hard, where it would pop up when the RPMs were around 1250. My engine sounded fine, but on one of the two occasions I got the light I could smell oil burning. But it was indeed low oil pressure, not a faulty switch, that then cost me 2 grand to fix.

What I'm trying to say is that guessing it's simply a bad switch and keeping on driving may cost you your engine. I would inspect the filter before continuing to drive it.

[richtung]

Just to update the thread.

The garage changed the oil pressure sensor/switch - its been 4 days and I've not had a engine pressure warning light since! Fingers Crossed that's sorted it.
The buzzing noise that i could hear from the alternator after the engine was turned off was the throttle bottle doing its thing apparently.

Was discussing with the garage about having the timing chain changed as preventative maintenance (car is on 92k miles). He was explaining that he doesn't think the VVT would need to be changed - mainly due to the cost of the part and the VVT doesn't usually fail. I'll decide closer to the time whether to fork out and get the VVT changed anyway.

One thing i forgot to ask, i've read about 3 sealing rings that can often fail - should i get these changed at the same time? Can the 3 rings be ordered individually or do these only come with another part?

Cheers