Just bought a 55 plate focus 1.8 tdci and noticed a hissing noise when I accelerate. I thought it was the turbo at first but after a bit of research I see it could be a faulty hose. Any tips on how to diagnose the right hose and how best to source a replacement would be appreciated. Also what are peoples opinions on getting the engine remapped, I see the potential for greater performance and economy, but the last thing I want is the car going into limp home mode as i drive back from Wales on a Sunday evening. I use the car for business so very high mileage is to be expected.

It's usually the top hose that pops.

A visual inspection for obvious splits and damp oily patches usually comes up trumps.

Ford charge about £60 for the hose as they insist on supplying the metal middle part too.

You can buy a decent silicone replacement part on ebay for approx £30.

If you do the work yourself make sure that the jubilee clips are positioned so that they don't rub any other part (particularly the expansion tank).

The job takes about 30 minutes and you only need screwdrivers and maybe a spanner set.

Mine is doing the same. I will check tomorrow. Thanks

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Welcome to the family, I had a 1.6 CMAX, there was a specific known fault on the 1.6's, however, I believe its the same part number and mounts on the 1.8.

Have a look at my signature "changing the intercooler pipe" this was a guide I did based on my CMAX and it saved me a lot of money. Not saying its definately this (agree to check for splits as suggested by Clive!) but its definately worth checking out as I found!