get them to strip it out and tell them you want an independant engineer to inspect it once the covers are of,f that will either scare them or prove to you that they have indeed changed the tensioner may be worth an oil pressure test hot and cold before they strip it,what grade oil did they use and did they change the filter,only other thing to check was if the bit of plastic between the cam sprockets was refitted as this creates a restriction in the top of the head it feeds tthe chain and keeps the pressure up so full pressure is retained within the oil gallery keeping the tensioner well feed, as i am sure that you know the tensioner is purely oil feed no ratchet, if they say there nowt wrong with it give it a damn good drive untill it starts to make a noise then drive it back to them,

hope it gets sorted, Regards TB

I've got a car with the same problem.

It had the rattle when I bought it, so I changed it with new sprockets, chain, guides and tensioner.

Made absolutely no difference. It had already been changed once before I got it, the parts I removed were still good. It's only done 40,000 miles.

I'm going to take it apart again soon and pay particular attention to three issues.

Firstly, the roll pin which holds the top of the right hand guide rail is missing. I shall obtain a new one. This could be the major problem.

Secondly, the chain has ground off alloy from the inside of the chaincase, alloy was in the oil filter when I got it. I shall ensure the oil ways in the head are clear and replace the chaincase with a secondhand item I already have, which will fix the oil pump if it is blocked with bits of chewed up metal.

Thirdly, this car has obviously suffered oil contamination in the past, as the camshaft journals are scored, probably due to the rattling chain and lack of oil chages. This may be leading to low oil pressure, but the warning light does not come on. I'll have a good look at this.

Typically, the rattle comes in when the engine is hot, around 2500 - 3000 rpm on a light throttle and disappears as load increases. Using 5-40 instead of 5-30 quietens it down a lot.

I have to sort it out as it's burning oil on cylinder 3, probably stuck or broken rings. What an amazing little engine.