Hello,

Other half has a 09 1.4 petrol and theres a couple of issues I'm looking to solve.

First off it seems to be losing coolant, but its not mixing with the oil (just done a change, oil looked like it should etc) and its not showing any signs of burning (no smoke etc). Now, I'm assuming its a very small leak somewhere, or possibly an airlock causing excess pressure thus leaking out the expansion cap?

 

Secondly, theres a slight hesitiation when accelerating from around 1krpm up to 2k. In my head it feels like it could be a leak in the intake, the car has no codes stored at all so that makes me think it cant be a misfire or bad spark. Chances of it being bad leads/coil pack?

on my 2007 fiesta 1.6tdci it had a slight leak which took a long time to find. it was coming from the plastic thermostat cover. I only eventually found it because I put some radweld in it. This cured it for a while but it leaked again it left a red stain (as radweld is red) from where it leaked which showed me where the problem was.  radweld is considered a bodge and the fibrous stuff, I am told, can cause other problems by bunging up places which shouldn't be bunged up but at least in my case it helped me find where the leak was. 

Might be a good shout, the car has done 115k so worn seals are probably the cause. Water pump was done last year with the timing belt so cant see it being that.

I had a 2001 focus 1600 petrol. I think this is same type of engine as your 1.4, but not 100% certain. On the font of engine, between engine and radiator is a black plastic inlet manifold, like 4 wide pipes next to eachother. Underneath this,close to the engine, running across ways with right angles at ends was a rubber pipe. Maybe about 2.5cm diameter. On mine, this was split allowing air in. I don't recall hesitation but more of a waivering tickover speed (higher than should be). This was a known place to look on focus of that era. Not sure if yours is same design / layout but if it is, have a look there.