Black scum in header tank???

[kingy1912]

Hi all,

My Blue HDi 100 has a black scum in the header tank with what looks like some kind of fines floating on top. Best way to describe it would be like a fine black coloured saw dust. There is no water in the oil and no milky emulsification in the header tank either. 

My initial thought is maybe the oil cooler as i feel its unlikely to be a head gasket if oil is travelling out the way in to the header tank. There is no exhaust smell from the header tank and it seems to hold pressure no problem. When you wipe your finger around the inside of the top end of the header tank it seems to clearly look like oil but the stuff in the coolant does not seem to behave the way oil does when it mixes with coolant.

Any suggestions would be helpful and if anyone believes it is the cooler do they know how hard it is to do or is it easier to go to the garage? Not really to bothered about saving cash unless it is a big job as it is a working car so is well maintained continuously anyway.

Thanks

[brodfather11]

I would drain it and flush it with a dishwasher tablet in the mixture . It could be the inside of a hose or radiator/heater matrix which has had a sealer put into it sometime and is now peeling off.

I've had an oily stuff, looked like lumps of grease, in the header tank and flushed with the dishwasher tablet , it cleaned it up and never came back . As I wasn't the first owner I didn't know what had been done to it before.

[kingy1912]

Ok brodfather thanks for the response. It’s actually ended up in the garage due to an unrelated issue. I’ve went ahead and asked them to just flush and refill her while it is in. I can see how it goes from there and if it reappears.

It did have the thermostat and housing replaced about 4 months ago so not sure if it may be related to that in some way.

Thanks