Dipstick discolouration

Hi everybody. This is a great forum and has been of enormous help to me so thanks to all the posters.
I have a query about the engine oil on my MY2016 PHEV. I recently checked the oil level and was surprised to find that there is a discolouration where engine oil has been in contact with the metal of the dipstick. The metal has been transformed from bright and shiny to a matt, light grey. In case it was a deposit I tried using a plastic pan scrubber to remove the tarnish. This had no effect so I believe that the metal has been chemically altered. I have never seen this before on any of the many cars that I have owned. The car has only done 17000 miles and has been properly serviced by Mitsubishi.
Has anyone else noticed this on their PHEV and is it a problem?

Thanks,
Ian

I've seen this happen to many vehicles, not just PHEV's it's just a reaction to being continuously submerged in oil, it will have no adverse effects to the oil, the dipstick or your vehicle.

Edit :
Just checked a brand new PHEV , looks like it's the same.

Hi Rogue.
I was concerned that because my ICE frequently never reaches it’s correct operating temperature, especially in the winter months, the discolouration due to the oil might be a symptom of the conditions that cause the dreaded ‘Mayonaise’ inside the oil filler cap. The ‘Mayonaise’ (I must look up the correct technical term) is apparently due to water vapour condensing on cold surfaces inside the engine. Presumably this moisture then contaminates the oil until the ICE gets hot enough to make it evaporate. I haven’t seen any signs of the ‘Mayonaise’ yet. Hopefully Mitsubishi have designed the ICE to be able to cope with short runs!

Thanks.

Got these from a brand new unregister 18MY and a 2014 registered PHEV which was in with us.
Sorry they are a little blurry.

https://i.imgur.com/RCE21tN.jpg

https://i.imgur.com/WylyQRW.jpg

The ICE is pretty resilient and the vehicle will normally tell you if there is anything it doesn't like. The "Mayonnaise" effect is these days a thing of the past.

Looks like Rogue beat me to it. I'll add another photo (from a 2018 with just over 4000 km) anyway just because.

View attachment 4000km2018.jpg

If the oil's leaving a varnish layer, it'll be caramel brown. FWIW

I, hopefully, have attached a photograph too. I’m not concerned about engine damage now thanks to both your replies, but I do find it interesting that the oil has reacted with metal in this way. As I said in my initial post, the tarnish will not rub off and appears to be due to a chemical reaction. Oil is supposed to protect metal! :?

Thanks.

That 'greyish' look isn't tarnish - it's just a texture on the stick (like sand blasting metal or frosted glass). My guess is that it keeps the oil film from running and makes it easier to judge the oil level. You could test this by putting a drop of oil on the frosted part and the shinier part and observing the oil drop as you move the stick from horizontal towards vertical.

Hi Andy.
Becuase of the irregular edge to the ‘discolouration’ I assumed that it was due to immersion in oil. Your idea that the change in texture is manufactured, to prevent oil run off, makes sense.

Thanks.