Hi, just enquiring if anyone has come across anything like this before and if they got it sorted. I have a 2010 Skoda octavia 1.6 tdi elegance with 181000 on the clock it has always had a regular yearly service since I have owned it since 2014. Recently the flashing red oil light came on as I went onto the motorway and it went into limp mode straight away so I pulled onto the hard should and the engine cut out, AA towed me to garage where we discovered the oil pump belt had snapped, so they replaced the belt and the cambelt, oil and filter. Picked car up drove for about quarter of mile light came back on. Straight back to garage where they replaced oil pressure switch (genuine one from tps), drove it light came back on when engine reached normal temperature, back to garage they replaced oil pressure pump, drove it, light back on again when reaching normal temperature,(engine is not overheating and there are no oil leaks) back to garage they have checked oil pressure levels and they are fine but a little low on idle, have put some swp oil additive in engine and drove it from garage no light as of yet but have only drove it for about 1 mile since picking it up so not convinced just yet will be taking it for a drive today, fingers crossed. Must be cleanest engine in UK at moment as has had 3 oil and filter changes in two weeks. Also garage has said it should be fine as pressures are OK and it could be an electrical issue. I am just a bit stressed as it may still not be sorted and have spent nearly £1000 on it now, car not worth that I know but started with a £400 fix and just escalated. Also light doesn't come on at start up or when engine is idling only when driving and it reaches normal temperature. Any advice would be appreciated and thank you for taking the time to read this. 

There must have been a reason for the oil pump belt to snap like that.  Is the pump itself making any noises?  My other thought is that the pump is in the process of failing and the oil pump belt failing - was the car's way of say - I need a new oil pump too.  You have oil pressure, but seemingly - just not enough.  There is either blockage in the pump / pump pickup or the pump is failing.

3 minutes ago, Subby1345 said:

have put some swp oil additive in engine

What's that supposed to do?

Which oil has been used for all these changes?

I'll check circuit diagrams in a bit if you can tell me the engine code, but I think there's just the one oil pressure switch.

It may be rated at a pressure where it would 'nuisance trip' sometimes at idle, so the software that runs the pressure monitoring system ignores it below 1500 rpm (except when cranking), which may explain why you don't see the light when idling, but only when driving.

Try driving at 1400rpm for a while with fully warmed up engine, then increase to 1600 and see if you then get a warning, as a test of this theory.

 

What pressures have been measured at what rpms, and was the engine at full operating temp when they were being measured?

Hi the engine sounds really good no noises at all the pump including pick up pipe has been replaced with a new one, pressure is OK so just don't understand why light is still coming on, the belt is a rubber one not a chain and they said it does wear out just like a cambelt. 

Other idea - blocked oil pickup, meaning you can get pressure but not flow?

Oil pressures they showed me on a computer in garage and showed me on the pressure gauge while it was plugged into the engine. Readings were just above zero on idle and just above  2 bar when revved, Engine was at normal temperature when being tested. Said swp engine treatment would thicken oil up and might help it pressure wise. 

Oil pump and pick up pipe replaced with new ones, has also had 3 oil changes and been flushed in the last two weeks

1 minute ago, Subby1345 said:

Readings were just above zero on idle and just above  2 bar when revved

Not specific enough.

Which oil is in the engine? 

By the way Thank you for your comments, and there is only one pressure switch with a single wire connector which has also been replaced with a new one. 

Not sure about oil as just let local garage do the work

Some info on testing pressures here: Skoda Workshop Manuals > Octavia Mk2 > Power unit > 1.6/55; 66; 77 kW TDI CR Engine > Engine lubrication > Removing and installing parts of the lubrication system > Testing oil pressure and oil pressure switch (workshop-manuals.com)

 

 

"Oil pressure when engine idling: at least 0.08 MPa (0.8 bar).

Oil pressure at 2000 rpm: min. 0.15 MPa (1.5 bar)."

Edited 23 July, 20214 yr by Wino

Wino, thank you The pressures sem to be OK with what the garage showed me. I'm not sure if this is the engine code you asked for as was under the bonnet and on the inside of passenger door but this is the number TMBGT21Z5A2061784

36 minutes ago, Subby1345 said:

Said swp engine treatment would thicken oil up and might help it pressure wise.

Well yes, in principle, presuming you've misremembered and mean STP oil treatment. I'm not sure I like the use of oil treatments to change the chemistry of the oil.

9 minutes ago, Subby1345 said:

Wino, thank you The pressures sem to be OK with what the garage showed me. I'm not sure if this is the engine code you asked for as was under the bonnet and on the inside of passenger door but this is the number TMBGT21Z5A2061784

 

I would get the pressures checked again. Possibly at a garage that hasn't been involved so far.

That's your VIN, not engine code. Engine code can usually be found in a few places; at start of engine number on V5 ownership document, on sticker in boot showing build options, on barcode sticker on upper cambelt cover (letters in front of engine number). Boot sticker sometimes duplicated in front of service book.

 

Ask garage which (exact) oil is in the engine. Might be on invoice? 

 

Yes sorry i did mean stp oil treatment, I don't usually use oil treatments myself but the garage recommended and I would try anything now. 

3 hours ago, Subby1345 said:

Yes sorry i did mean stp oil treatment

Kewel. "swp" is actually a thing too, just not in this context. The only oil additive I've ever used was Molyslip, which increases lubricity rather than viscosity (actually viscosity is the enemy of lubricity, and hence of flow rate). Gallery oil pressure is a bit of a red herring, because bearing oil pressure is measured in hundreds of bar rather than just tens of PSI.

Edited 23 July, 20214 yr by KenONeill

Just for reference as the I am not sure the question has been answered, the 1.6Tdi has a Common Rail engine with engine code CAYC.

 

Thanks @pikpilot. So the pressure switch (marked in red. herring or otherwise )  has a rating described as 0.3-0.6 bar.

 

 

 

 

 

So your oil pressure is dipping below 0.6 bar at around 1500 rpm sometimes, if my understanding of the warning system is right. 

That's clearly not consistent with it being more than 0.8 bar at idle, as the test instructions suggest it must be.

 

Unless the warning system is malfunctioning, or doesn't function like I've described, but I've suggested a way to check that already.

 

 

Edited 23 July, 20214 yr by Wino

On 23/07/2021 at 10:00, Subby1345 said:

Oil pump and pick up pipe replaced with new ones, has also had 3 oil changes and been flushed in the last two weeks

181,000 miles and a flush and 3 oil changes. Have they done a compression test?

 

Yes sorry i did mean stp oil treatment, I don't usually use oil treatments myself but the garage recommended and I would try anything now. 

UPDATE: Oil pressure test was done and it was a little bit low on idle but fine when revved. Since I put the oil treatment in the light has only come on once but i had driven on motorway and it came on while driving around town and revs were under 1500. The light was coming on quite frequently before I put the STP oil Treatment in. So I am now thinking it can't be electrical as surely it would still come on as often as before no matter what oil was in the engine. Also I have had the pressure switch tested and it is getting the correct electrical current. 

OK, so what was the pressure at idle?

 

Maybe on diesels the 'below 1500, ignore' threshold thing I mentioned is set lower. Would make sense as they generally operate at lower rpms.

 

Something else to check before getting too worried - is the engine running hotter than it should be? 

Difficult to tell from the coolant temp gauge as they use 'customer soothing software' to make the needle reluctant to move off the middle. 

Oil temperature readings may give a clue though, see what they're doing in various driving conditions.

 

Might be something easy like a dodgy radiator fan.

Hotter oil = thinner oil = lower pressure.

1 hour ago, Wino said:

Maybe on diesels the 'below 1500, ignore' threshold thing I mentioned is set lower. Would make sense as they generally operate at lower rpms.

I'd suggest 1_200 rpm, based on where I short shift in town.

WhatsApp video of pressure test from garage attached, hope this is helpful 

It does look well below the 0.8 that the test suggests is minimum at idle;  depending on gauge accuracy and zeroing.

I don't know what to do now I have been out in car today with no light showing and the garage reckons it is temperamental and will be fine and to ignore the light as the engine would cease up if i drove it at all if anything was seriously wrong with it ??