I'm suspecting a leak at the temperature sensor block (B40/1), since that thing is completely covered with dirty black stuff.
Is there anyone that has experience with a dirty mess like this (what could it be caused by?), cleaning the temperature block, including replacing all the o-rings?
I have an overview of the o-rings of the valve block, but not for the temperature block.

I'm planning on replacing hose 50 (if that contains rubber close to the temperature block), 65, 70 and 100 (according to the last diagram)
Also, which hose is the hose that you'll need to raise the engine for in order to install it (I hope it's not one of the hoses I'm planning to replace)?

Do you recommend to replace more hoses?


That's the top of B40/1, the temperature block, which is pretty much black


B40/1 in all it's dirty glory


The dirty mess around the front pressure release valve

The hoses right below the front accumulator, which are a bit moist

I don't think this is hydraulic fluid, since I took a paper towel to let it absorb the pool on the right, and took a smell test.


I'll be replacing the accumulators on both sides, since this one has rust on it.


This looks fine

The right rear hydraulic line looks terrible


The right rear hydraulic line going to the strut


ABC front hoses overview