Oil contamination on timing belt on my mondeo xr5
 

I recently had to change the oil filter housing on my mondeo. All seemed fine but since I have noticed oil coming from the timing belt cover. Looking inside there is contamination on the timing belt (only a little) and on the aux belt. So I assume that the excess pressure in the engine before changing the filter housing has pushed oil past the cam oil seals.
The oil has never needed topping up so the amount must be fairly small.
More worryingly I noticed some frothing in the oil cap today that was not there when I did the work a few weeks back. Obviously I have changed the oil too, and since only done short journeys. Still, worried about the head gasket. There does seem to be water in the exhaust but as the engine barely gets warm I can't say for sure. In the past I have had to top up the coolant but only twice in 18 months so it's not being used at a high rate .Will have to check for air when it's running.

My question is how much of a ball ache are the head gasket and, more importantly as I'm sure they need doing, the cam oil seals on these 2.5t engines? And what specialist tools are needed to complete the jobs?
Afraid I've not got the cash to pay anyone to do them at the moment so it's looking like my week off will have to be used instead, boo!

My old focus st used to get a lot of sludge in the filler cap when I used it for 7 mile each way trip. Take it for a good long run.

That's the plan tomorrow morning. Cheers for that though mate, put my mind at ease a little.