Diesel in the oil? Really?

[Argos69]

Good day fellow Citroen sufferers,

After resolving the latest Eolys problem, the car has thrown up another good one.
I'm travelling a fair way tomorrow and checked the oil level. It was nearly a centimeter over the max mark!
Now, I know this was a bit below the last time I checked (I have a minor oil leak down the bulkhead side of the engine, so I check regularly-ish).
The oil smells and feels pretty normal to me.

First thought was coolant due to head/gasket maybe?
Bought a RELD kit and the blue liquid stayed blue, so no Co2 and I'm hoping the head/gasket is ok.

So what next - diesel?

I've tried the highly scientific drip test on a sheet of paper (photo hopefully attached) and it's not 100% conclusive, what do you think?
I've added a drop test of some clean oil just to see how that spread and there's not a vast amount in it.

So, I've lowered the oil level before my journey, but would welcome your thoughts and advice please.
C5 Tourer Exclusive, 2013, Automatic, 2.2HDi

[Skull]

...Now, I know this was a bit below the last time I checked (I have a minor oil leak down the bulkhead side of the engine, so I check regularly-ish).
The oil smells and feels pretty normal to me.

If you've ruled out coolant with the test kit, it really has to be diesel doesn't it There does look to be some seperation in your photo

Monitoring required to see how much the level rises, over mileage covered.

[Argos69]

Hi Skull & thanks,
Yes agreed. I shall monitor, but don't have the expertise to come up with a scientific starting place for a list of Diesel suspects. Injectors perhaps?
I've bought a bottle of concentrated injector cleaner and shoved it in the fuel tank. When I get over to France I'll have a listen to the injectors, check the resistances and properly check with Diagbox, but I'm loathed to try to remove them when I'm so far away from familiar suppliers and easy next day deliveries!
As for monitoring, I've taken under a 1/4 litre out today, but obviously if the oil is regularly watered down with diesel, it won't really be "oil"
I still love the car, but it's rapidly becoming an abusive relationship! If the ride quality wasn't the best I've ever experienced, it'd be easier to condemn.

[Skull]

Argos69

A possible analysis/sample kit may be worth the money

https://aaoil.co.uk/product/oil-analysis-kit-2/

I've only ever heard of this problem recently whilst researching a faulty EGR system, as you say there are numerous other potential faults though

[bobins]

A mate was getting that (fuel in the oil) regularly on his diesel pick-up truck - it was a known issue and down to too many short trips where the truck was doing aborted (or sub-optimal) DPF regens.

[PaulC5]

Was a quarter of a litre enough to get the level below the max mark ? A risk of a high oil level is for the engine to run on the oil and not stop until you stop the air flow or the engine seizes.

[Estately]

Hi,
We have the 2.0L X7 2013. We tend to note down fuel purchases and over time with our motoring it does about 10 miles per litre.

It is obviously less miles, local journeys, winter.

Maybe you can come to some idea of your fuel consumption with the various types of journey that you do.

Could you identify a change or worsening in fuel consumption which might back up your injector theory?

Hope that is a little help.
Andy.

[Jay-Bruce]

You get UV reactive dies for checking oil or fuel leaks, I'd suggest you put some in the fuel filter, drive the engine for a day or two, then use a uv torch on the dipstick, if the opil on the dipstick is fluorescing, then you have diesel in the oil. As for how it's getting there, hmm... Only thing I can think of is where is the High Pressure Fuel Pump on these engines? Is it mated to the camshaft? Maybe the pump is weeping fuel into the head and the fuel is working its way back to the sump through the oil return galleries?

https://www.ebay.co.uk/itm/234722869101

[Argos69]

That's a really good idea.
For me, as I currently have a small oil leak down the bulkhead side of the engine, the leak dye would be a real help to try to trace that too. I'm away in France for a bit at the moment, so I'll find someone who'll send it to France.
Anyway, that looks like a plan, so thank you for that.