Oil Pressure Warning Light coming on!

dickhilt

Member
Couldn't find anything in a search of the threads, so advice please?

Very occasionally the oil pressure warning light comes on but then goes off again after a short distance. This happened today on a three mile trip from cold. Car was then left for around two hours and light did not come again for the journey home.

The car has used very little oil in my ownership and I've only topped it up twice with around half a litre in the last eight thousand miles. There's no oil leak, no smoke on start up or under acceleration, the car runs perfectly and still returns 70 mpg regularly.

The service indicator shows 1500 miles to next service and it is a 2001 '51 car with 37500 miles on the clock. The last service was at around 15000 miles in September 2003, but, the supplying non-franchised dealer insisted on doing a 'service' involving an oil and filter change. Despite my insistance that they use the correct specification long life oil, I've no proof that they did so and that was at 29000 miles.

Any suggestions? Might I be looking at a big bill?:(

Cheers
 

Skipton01

Well-Known Member
dickhilt said:
Couldn't find anything in a search of the threads, so advice please?

Very occasionally the oil pressure warning light comes on but then goes off again after a short distance. This happened today on a three mile trip from cold. Car was then left for around two hours and light did not come again for the journey home.

The car has used very little oil in my ownership and I've only topped it up twice with around half a litre in the last eight thousand miles. There's no oil leak, no smoke on start up or under acceleration, the car runs perfectly and still returns 70 mpg regularly.

The service indicator shows 1500 miles to next service and it is a 2001 '51 car with 37500 miles on the clock. The last service was at around 15000 miles in September 2003, but, the supplying non-franchised dealer insisted on doing a 'service' involving an oil and filter change. Despite my insistance that they use the correct specification long life oil, I've no proof that they did so and that was at 29000 miles.

Any suggestions? Might I be looking at a big bill?:(

Cheers
I had a very similar situation on my 2001 A2 TDiSE - it was eventually resolved by replacing the oil pressure sensor AND the dash pod! Apparently the pod was changed as a belt and braces solution.

Cheers,

Mike
 

dickhilt

Member
Thanks Mike,

I'm beginning to think it must be the sensor. Hasn't come on today and probably only around three times in the last thousand miles.
Any idea what's involved in changing the sensor?

Could the oil coming to the end of it's life cause a drop off in oil pressure?

Cheers
 

Skipton01

Well-Known Member
dickhilt said:
Thanks Mike,

I'm beginning to think it must be the sensor. Hasn't come on today and probably only around three times in the last thousand miles.
Any idea what's involved in changing the sensor?

Could the oil coming to the end of it's life cause a drop off in oil pressure?

Cheers
I'll be honest with you - without checking out the manuals, I've no idea of the work involved in changing the oil pressure sensor - perhaps Spike or Robin would know off-hand.

I doubt that oil approaching the end of its life would cause the problem though.

My light was very infrequent too.

Cheers,

Mike
 

spike

Well-Known Member
Hi dickhilt
The oil pressure sensor is located on the side of the oil filter housing so it should be fairly easy to change. The actual oil pressure can also be checked by plugging a gauge into the tapping when the sensor is removed.
The oil would need to be left in an awful long time before the viscosity degrades significantly enough to affect oil pressure. If the oil was so bad, the symptoms would be there all the time so it's unlikely to be an oil problem.

Cheers Spike
 

robin

Member
HI dickhilt

It is just as Spike says just get new sensor but do not over tension when puting the new one on just nip it up.

hi Spike you just got in befor me.

Cheers

Robin
 

dickhilt

Member
Mike, Robin, Spike,

Thanks a lot for the advice.
The symptoms are;

Switch engine on from cold, goes through it's checks and shows OK. Sit with engine ticking over for a while blipping the throttle etc.........nothing.
Set off driving and after a few hundred yards, three bleeps and oil pressure light comes on. Short journey (3 miles) engine not up to temperature and leave car. On starting the car up 20 mins later, nothing. A long spirited drive of twenty miles, no warning light and car performing perfectly as usual.
Maybe I'm being a bit reckless, but it all seems to point towards a faulty sensor, rather than low oil pressure?

Could the old one just be dirty and need a clean? If it's goosed, am I likely to get the sensor cheaper at a VW dealer?

Only other fault at the moment is the fuel filler cap releaseswitch has packed up, so it's into the boot to open it manually at the moment!
 

Skipton01

Well-Known Member
dickhilt said:
Mike, Robin, Spike,

Thanks a lot for the advice.
The symptoms are;

Switch engine on from cold, goes through it's checks and shows OK. Sit with engine ticking over for a while blipping the throttle etc.........nothing.
Set off driving and after a few hundred yards, three bleeps and oil pressure light comes on. Short journey (3 miles) engine not up to temperature and leave car. On starting the car up 20 mins later, nothing. A long spirited drive of twenty miles, no warning light and car performing perfectly as usual.
Maybe I'm being a bit reckless, but it all seems to point towards a faulty sensor, rather than low oil pressure?

Could the old one just be dirty and need a clean? If it's goosed, am I likely to get the sensor cheaper at a VW dealer?

Only other fault at the moment is the fuel filler cap releaseswitch has packed up, so it's into the boot to open it manually at the moment!
Hi Dick,

I am inclined to think it's a dicky sensor myself and this will be the simplest and cheapest thing to replace (less than a 4litre oil swap!).

It's unlikely that the old switch would just need a clean - they don't really work like that and a sensor would be the same price at either Audi or VW - the parts prices are without exception, harmonised.

The switch for the fuel release could be goosed too, but is more likely to be either a loose connector or a faulty solenoid - these are not unheard of.

Cheers,

Mike
 

Rusty911

A2OC Donor
Cor, what a dusty old thread, stumbled over it one day after its thirteenth birthday.

Why am I here? Have been using the rescued Devon car on and off during last couple of weeks and it's done alright. Right up until this evening when the red oil (pressure) warning went off.

Oil level fine, oil changed about 200 miles ago, quality oil, quality filter. No nasty noises from balance shaft area and oil light off at idle. As revs came up to about 1500, the warning sounded. Randomly it would disappear, mainly when idling. Had a chat with @depronman and we agreed that a) there's a good chance it's the sender, b) as warning doesn't chime at idle, nurse the car home at just above idle, which I successfully did.

Now it's home, restarted and all seems fine again. I appreciate next sensible move is to find an oil pressure test gauge and try that, but out of interest, are there any / many oil pressure sensor failures amongst us TDI owners?
 

Rusty911

A2OC Donor
bloody hell Barry were did you find this thread from 2007 :)
I flicked Google to 'prehistoric only' 😀 Clearly the Devon car is one of a kind as it runs through, one by one, every possible fault an A2 can suffer. To be fair, the stereo still works and the steering wheel's not fallen off yet.
 

depronman

A2OC Donor
I flicked Google to 'prehistoric only' Clearly the Devon car is one of a kind as it runs through, one by one, every possible fault an A2 can suffer. To be fair, the stereo still works and the steering wheel's not fallen off yet.
It’s just trying your patience
It will give up one it realises your will always win or you will have rebuilt it completely bit by bit

Paul


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66Beetle

A2OC Donor
This may be completely irrelevant but some years ago the Oil Pressure Warning Light used to come on on our 1966 Beetle. I thought it was genuine low Oil Pressure. Tried all sorts inc. New Switch, up rated Oil Pressure Relief Valves / Springs. Eventually found out that the Wire to the Switch had a bit of Insulation missing, so it sometimes shorted out whilst driving. Fixed by a bit of insulation !

Good luck.

Steve
 

Rusty911

A2OC Donor
This may be completely irrelevant but some years ago the Oil Pressure Warning Light used to come on on our 1966 Beetle. I thought it was genuine low Oil Pressure. Tried all sorts inc. New Switch, up rated Oil Pressure Relief Valves / Springs. Eventually found out that the Wire to the Switch had a bit of Insulation missing, so it sometimes shorted out whilst driving. Fixed by a bit of insulation !

Good luck.

Steve
Thank you Steve. Funnily enough it occurred to me during the night that I'd done the screeching starter motor a week or so ago which moved the wiring in this area. Had a quick look at the wire routing today. Appears O.K. but it is the lowest wire with quite a heavy stack on top. Certainly won't rule out wire damage just yet. Paul had suggested giving the wiring a general wiggle with engine running to see if the warning could be triggered this way.

I'm trying to hunt down a pressure test kit (to no avail so far), but I am picking up a new sender anyway. What I thought might be interesting would be to put the meter on the existing one and see exactly when it does what, and then compare that to the new. Annoyingly the only sender I can get is an aftermarket (rather than OE or OEM), so there will also be the slight niggle that even the new sensor might not be accurate. I'd hope it's 'good enough' as hardly the last word in technology and all it needs to do is register, what 1 bar or so: not rocket science.
 

Rusty911

A2OC Donor
Well, what a curious little car these are!

Background: no oil warning until revs come up to 1800 or so. Warning fires for a while after revs return to idle, then display returns to normal. If you rev back up another couple of times, oil pressure fires at lower revs and won't go out until car restarts.

Went to fit test gauge borrowed earlier, and found I'd failed to plug the sender back in after pulling plug out to check the colour / type of sender earlier today! Symptoms were identical to sensor being plugged in. Therefore can only think there is a tolerance within the cluster where it'll ignore a zero signal situation from the sender at low revs and cancel one or two low pressure readings (i.e. open circuit) after a while. Once it sees (or perceives) low pressure after this, warning remains until ignition switched off.

Tried the gauge and oil pressure is actually textbook, very good in fact.

Sent the car through 10-15 start, bring revs up, fire warning, back to idle, ignition off cycles with old sender: warning fired every time. Then fitted new sender and did the same number of cycles: no warning. Coupled with the physical gauge readings, I'm calling this good.

@depronman thank you again for your help!

Next project is to get to the bottom of the low fuel warning despite the full tank ...

Oh yes, both senders read open circuit at zero pressure / engine off. New one reads full continuity with engine at idle and upwards. I've no doubt if I put the original sender back in it would remain open throughout. The odd cluster behavior above explains why no warning at idle (which you'd normally expect: i.e. fire oil pressure warning at any time).
 
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depronman

A2OC Donor
Cluster or wiring from sender unit to cluster
It’s is the car that just keeps on giving a mechanics wet dream
Good news on the measures oil pressure

Paul


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Rusty911

A2OC Donor
Cluster or wiring from sender unit to cluster
It’s is the car that just keeps on giving a mechanics wet dream
Good news on the measures oil pressure

Paul


Sent from my iPhone using Tapatalk
Apologies Paul, my post has been completely re-written since your reply in light of new sender working and better wording of cluster behaviour.

Therefore hoping the low fuel level issue is separate from the (now sorted?) oil pressure warnings.
 

depronman

A2OC Donor
Nice when what you have been a very serious issue turns out to be a £5 sensor
I’ve had them start to leak and fill the plug with oil but still work ok other than a drip or two of oil out of the connector end


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