I've been looking at getting a Berlingo 1.5 Blue Hdi but concerned about he 7mm camchain issue (this is the small chain/tensioner linking the two camshafts in the 16 valve head, not the main drive cambelt). I;d wondered about getting the car and then simply fitting a new 7mm chainat intervals (much like changing the cambelt). However, I have just read this information from an engine part supplier which I think shines a very interesting light on the problem and why it cannot easily be fixed once symptoms arise...
"When replacing this 7mm timing chain kit, you must inspect the camshaft sprockets for tooth wear or changes in profile shape. The reason this chain fails is that, over time, the original chain wears the teeth on the camshaft sprocket. The worn teeth can look similar to a shark's fin profile. If the teeth on the original camshafts are worn or misshapen, you will need to replace the camshafts. We offer replacement camshafts which retain the original housing as a direct replacement, although it is recommended to upgrade to the modified 8mm / 22-tooth cam sprocket version. We can supply the complete housing and camshaft kit, which contains the newer modified 8mm / 22-tooth cam sprocket version. This is proving far more reliable than the 7mm version. However, it is still good practice to replace the chain and tensioner as preventative maintenance on both the 7mm and 8mm versions. Failure to replace the damaged camshaft sprocket will cause premature chain and tensioner failure, which can lead to extensive engine damage."
From lymmengineparts website