Hi guys, 1st time poster here. Just after a bit of advice. 

Right here goes, I've got a 62 plate 1.6 focus titanium tdci econetic. I bought it with 77k on the clock just over 3 years ago and it has been used as private hire taxi since. It's now got 228k on the clock, has been serviced regularly obviously. So I've been averaging 50k a year, probably 15-20k of that are motorway miles.

I've been losing coolant recently and it's gotten worse. Probably having to refill once a day or 2. Took it to my usual garage and they couldn't find any leaks, so did a pressure test, which slowly lost a little bit of pressure. Then  a sniff test which was inconclusive at first but they tried again and the blue chemical turned slightly green. They diagnosed that it's my head gasket and will either need replacing and skimming, or new engine worst case scenario. 

I've been going to his garage for years and he said he'd had 2 or 3 focus's in recently with the same problem. And each time he's the sent head off to be skimmed and it hasn't worked and they needed a new engine after all that.

He said he can try to do head gasket, but you're already a few hundred quid in already just to get the head off and purchase new gasket. Then skimming and reassembling could total 400-500 and may or may not work. 

Should I just plump for a new engine from a hopefully reputable scrap yard with low mileage for between 600-900 and fitting for maybe 500 ish? A decent engine could hopefully get me another 2-3 years at an outlay of 1500ish. Or should I try fixing the head gasket itself. Anyone had similar problems? Cheers for any advice.

It could be the EGR cooler leaking rather than the headgasket so it might be worth checking that as the cheaper option.

Personally I'd go for a low mileage engine, at 228k all of the engine parts are likely to be getting worn and no longer working as efficiently as they could, losing you some power and fuel economy.  Which will only get worse over the next few years, even after the outlay on the HG repair.  Having said that, a used engine is always a gamble as you don't know how it was treated before.

I must admit, I can't say I've seen any 1.6TDCi Mk3's blow the headgasket on here or the facebook pages, I was fully expecting it to be an EcoBoost engine when I saw the title!