Oil level too high - sold the car!

[Wingtank]

I got rid of my ‘18 plate S90 D4 Inscription in May, for exactly the same reason.

It was 7 months old when I bought it and during my ownership it went back to Volvo twice for the ‘oil overfilled’ warning. On both occasions an oil and filter change was done under warranty but as the warranty was due to expire any further problems would be down to me as the fault was “because of my driving style”! The dealer wouldn’t entertain any discussion about the DPF active regeneration and oil dilution problems despite them being a known issue.

I never really gelled with the car, particularly the noisy and unrefined Diesel engine and only average build quality and materials. It’s also my opinion that some of the supposed safety features relating to collision avoidance and traffic sign recognition braking are positively dangerous. Calling Volvo a premium brand is a real stretch.

On the day it was sold and driven away I was a very happy bunny.

[OldEngineer]

Originally Posted by Zebster

I've never understood how an interrupted DPF regen can lead to a significant rise in sump oil level. I realise that during the regen cycle additional diesel is dispensed into each cylinder during the exhaust stroke, but surely when the engine is switched off (even if the regen cycle is still in progress) the injection of fuel will immediately cease while the engine's rotational inertia (surely a couple of rotations?) lets each cylinder pump out practically all of the unburnt fuel last injected, leaving only the tiniest trace to percolate down to the sump via the piston rings?

And why are only some examples of the VEA engine troublesome in this regard? I give absolutely no consideration to DPF regen in my driving style, yet somehow my car just does it's thing keeping the soot level low and never causing my engine oil to rise. Is the rising oil level issue really a symptom of another problem?

It's the diesel wiping off the oil protection on the cylinders. It attacks this oil coating and then flows past the piston rings into the sump.

The diluted oil is also not providing sufficient protection in later stops. So cycle of wear is started that ruins the engine.

If you are offered a low mileage diesel car you need to walk away. Unless the low mileage is made up of long runs with no cold stop/starts in between.

And, of course, this problem is nothing to do with Volvo quality. The replacement Peugeot will go the same way if it suffers cold stops (which a Hybrid is more likely to do). Hopefully the new one is a petrol?

[Zebster]

Originally Posted by OldEngineer

It's the diesel wiping off the oil protection on the cylinders. It attacks this oil coating and then flows past the piston rings into the sump.

The diluted oil is also not providing sufficient protection in later stops. So cycle of wear is started that ruins the engine.

If you are offered a low mileage diesel car you need to walk away. Unless the low mileage is made up of long runs with no cold stop/starts in between.

And, of course, this problem is nothing to do with Volvo quality. The replacement Peugeot will go the same way if it suffers cold stops (which a Hybrid is more likely to do). Hopefully the new one is a petrol?

But why would diesel be left in the cylinder to run down into the sump? The fuel injection would cease immediately when the vehicle 'ignition' was switched off, even though the engine would then still undertake a few revolutions due to momentum that would clear the cylinders. In any case, even if the last spurt from an injector was left in one cylinder then it'd only be a fraction of a CC, so it seems unlikely that this tiny amount could cause the sump volume to increase by 0.5L (e.g. the alarm level) even after time.

Surely such a significant amount of diesel being accumulated in the sump is far likely to be caused by one (or more) leaking injectors, potentially allowing the entire pressurised volume in the rail to be discharged?

[RS3100]

Originally Posted by Zebster

But why would diesel be left in the cylinder to run down into the sump? The fuel injection would cease immediately when the vehicle 'ignition' was switched off, even though the engine would then still undertake a few revolutions due to momentum that would clear the cylinders. In any case, even if the last spurt from an injector was left in one cylinder then it'd only be a fraction of a CC, so it seems unlikely that this tiny amount could cause the sump volume to increase by 0.5L (e.g. the alarm level) even after time.

Surely such a significant amount of diesel being accumulated in the sump is far likely to be caused by one (or more) leaking injectors, potentially allowing the entire pressurised volume in the rail to be discharged?

It's not just the small amount of fuel left in a cylinder when the engine is switched off. It is a continuous process that happens during regeneration cycles.

https://www.jstor.org/stable/26273272

I'm no expert, but the issue affects many more vehicles than Volvo. It seems that vehicles which have the DPF situated further from the engine are prone to greater problems, partly because it is more difficult for the engine post-injection cycles to achieve suitable DPF temperatures to complete the regeneration cycles.

My Volvo is a petrol car, but I know that many diesel vehicles including my van can suffer from oil dilution. My van has a built in software algorithm that monitors a variety of sensors and external conditions, from which it "calculates" (guestimates) the likely conditon/dilution of the oil due to the number and type of regeneration cycles, and displays a warning when or if it considers that the oil should be changed before the normal service interval. If the warning is ignored, the vehicle enters limp mode a short time thereafter, and if further ignored, refuses to start until the system has been reset - hopefully following an oil change, but some owners are just resetting the warning system without changing the oil by following YouTube type instructions and because they don't understand the logic!

Modern DPF compatible oils are engineered for use with up to something like 9% oil dilution by fuel, from memory, by which time however they are often barely capable of meeting the grade criteria from what I have read.

[tronicx83]

Exact same issue with the LR Discovery Sport that we’re handing back in January (and replacing with a XC90 T8) - oil dilution. Land Rover know the problem and have even got a sensor to detect the dilution level which then triggers an oil service message. LRs answer is to just regularly change the oil- which they’ll do for free under warranty- and then charge a fortune for afterwards.

[larchdale]

Yes, it's a petrol.

[Bulldogfour]

Originally Posted by tronicx83

Exact same issue with the LR Discovery Sport that we’re handing back in January (and replacing with a XC90 T8) - oil dilution. Land Rover know the problem and have even got a sensor to detect the dilution level which then triggers an oil service message. LRs answer is to just regularly change the oil- which they’ll do for free under warranty- and then charge a fortune for afterwards.

I traded in my Disco Sport earlier this year for the same reason. Monitoring the DPF regen status via the OBD2 port all the time via an app drove me bonkers.

[larchdale]

Hello Zebster,

I asked my dealer if the problems might be a symptom of something more profound. Our neighbour (a GP) drives a 2018 diesel XC60 almost exclusively on short trips related to work and has never had any issues. My car was a 10-month old ex-Volvo management car when I bought it, so perhaps the problem originates in the 10k miles it did then. Regardless, the dealer would not investigate the root cause, and Volvo wouldn't acknowledge the issue or help with any costs incurred in searching more deeply.

I was bound to be the loser if both the dealer and manufacturer refused to back me, so I sold the car.

Cheers,

Iain

[Zebster]

Originally Posted by larchdale

Hello Zebster,

I asked my dealer if the problems might be a symptom of something more profound. Our neighbour (a GP) drives a 2018 diesel XC60 almost exclusively on short trips related to work and has never had any issues. My car was a 10-month old ex-Volvo management car when I bought it, so perhaps the problem originates in the 10k miles it did then. Regardless, the dealer would not investigate the root cause, and Volvo wouldn't acknowledge the issue or help with any costs incurred in searching more deeply...

I honestly believe the problem of rising sump oil level cannot be a side effect of particulate filter regeneration alone, nor simply the owners driving habits in relation to aborting regen cycles by switching the engine off before these cycles have completed. I realise this issue is not uncommon, however most examples of each model do not suffer this problem so, logically, it must be an issue related to specific examples of the model. My Volvo certainly does not suffer this problem, at least in the 42 months/30k miles I've owned it.

Very convenient for the dealer to blame the owner's driving habits though...

[Simmy]

any unburnt fuel is forced past by the massive compression a diesel engine has