Chimney - brown liquid running down walls!

Hi.
I have recently bought a house that's a bit of a project and is probably going to end up being a labour of love!

I'm a bit stumped with the chimney though. It is lined with clay pots, but then it has a steel liner that the previous owners had installed so they could have an oil fire in the fireplace. This liner is no good for a solid fuel burner so we are going to take it out and just have an open fire until we can afford a log burner.

The problem is that last week we noticed a pool of yellow/brown liquid in the fire place itself and it looks like it has run down the flue. We the noticed this liquid running down the walls of the bedroom directly under the chimney! I have had a look at the chimney and there is some brown staining on the render, but it looks quite old whereas the stuff inside is very new. What do I need to do. I have considered taking off all the render, repointing the chimney, replacing the flashing and re-rendering, but I don't want to do this if it isn't going to solve me problem!

Any help would be much appreciated. Thanks.

it is often condensation in the chimney, dissolving soot and tar deposits (so becoming brown) and soaking through the chimney or running through bad joints, where it leaves a brownish stain, usually on the plaster, when the water evaporates. It is difficult to conceal the tarry stain.

Usual cure is to ventilate the chimney top and bottom. If it had a metal liner, the space outside the liner would have been unventilated.

Tar deposits are worse from woodfires and coal than from smokeless fuel. Keeping the chimney hot enough to prevent the combustion gases to condense inside will help