Chain tensioner noise? Or .....????

[911mot]

Hi. Just trying to diagnose a noise with my mate's car (fellow pelican AFCuk).

It's a Euro SC with stock tensioners @ approx 110k (miles)

The way he described it made it sound to me like a chain tensioner gone bad, but it only did it at high rpm 4.5k onwards.

A loud mechanical rattle he said.
Like someone dragging a chain across a dustbin lid I asked?
Yes he said...

Well the thing is we have just got back from a road test and the engine behaved and sounded perfectly, all the way to 6k either gentley or full bore. Oil level, temp and pressure all normal. Loadsa oophm, no smoke, everything checks out OK.

What we are also wondering is could it have been pinking? At the time the noise occured it was hot out. We're in the middle of a heatwave here so temps are up all round. The average for fuel here is 97 ron (uk ron). At first I dismissed this due to the fact he heard it in 3rd, 4th and 5th gear, he's not running a turbo (shame) and the engine runs/idles sweetly and pulls like a train
.
Our next course of action is to drain and sieve the oil, check the screen, cut open the oil filter, and pull the chain covers for a look see. Although I doubt an intermittant chain tensioner fault will be too easy to spot.

So has anyone else had chain tensioner noise come and go? Is this even possible or do they go bad and stay bad (which is what I thought)
Anything else we should check?
thanks in advance guys, open to suggestions here...only six weeks from our 'ring trip too. D'oh...

[GothingNC]

Might be pinging.

Someone described as marbels rolling around in an empty coffee can.

[Early_S_Man]

911mot,

I would suggest pulling the spark plugs first!!! If detonation or preignition has been happening ... there should be visible signs on some of the plugs -- cracked insulator, heat 'blast' damage, etc.

[nigel911]

Chain tensioner failures are not cheap - wouldn't drive too much or run at 6000rpm until I found out what the issue was...