william stevenson

does anyone know about the timing chain jumping on a three cylinder 1.2 after oil change

DFMM

Yes, I have read of this on a forum. The plastic tensioner parts rely on clean oil filling a hydraulic tappet type of capsule, which pushes the bottom of the left-hand chain-guide. The complete kit of parts for tensioning the chain were revised in 2004, and cost £300 inc VaT & labour.
You cannot even expect to get a rattle, without the old-fashioned spring and pressure shoe, the plastic bits just break, and a slight jump will put the engine out of action, or worse, bend valves, at extra cost.
A neighbour's '03 reg car lasted 15,000 miles then broke the chain :--- new engine under warranty :-- another car on a forum lasted 35,000 miles.
General opinion is that well-serviced cars can expect 60,000 miles.
My Son's 03 reg car is getting the revised kit installed today, at 42,500 miles, after using engine-flushing additive prior to an oil-change. The SEAT garage uses fully synthetic MOBIL 1 engine oil, and I shall fork out on this thorough oil change every 6 months, as he does short miles in Aberdeen, and I have fitted Iridium-tipped clean-burning DENSO spark-plugs also, to keep the Cat. and oil clean.
The Cat. can last 100,000 miles, but sooty running has caused one owner on a forum, to renew his at 57,000 mile
s.