brown sludge type substance

[pugjohn306]

Well ok i lifted off my rad cap and noticed a brown like sludge substance on the cap and arround the filler neck now its not oily its kind of like a muddy substance i felt it didnt feel oily and when the bit i wipped off dryed (theres my clue it wasnt oily)it dryed like a dust could this just be a rusty sludge thats been worked through or should i be getting concerned...theres nothing pointing to hg so im not thinking there i do have a small leak in the water system somewere but cant find it i think its within the heater matrix area..i dont know any way like i said brown sludge substance kind of like wet mud....any ideas...

[Bertman]

I would probably start by draining the cooling system and giving it a good flush through. See if that cures the problem and go from there..

[John1.4]

you're right it is rust, as above flush the system and see if it comes back, use a good corrosion inhibitor in your fresh coolant

[pugjohn306]

Yeh i thought it might be iv flushed it before but ill do it again if not im gunna have to start looking at hg..

[306Dan]

Drain and flush your system then fill with only water and add a coolant system flush, run your engine up as par the instructions on the flush, then ditch it and refresh again, you'll be surprised at the colour the normal water will come out