Advice on rattle please?

[malcolm]

Just bought the E back from it's annual grease-up and service. The mechanic told me he'd tightened the alternator belt.
As I backed into the garage back home, a rattle started up on tickover. Seems to be coming from the front, around the fans/alternator etc. It stops when you increase the revs above tickover.
I looked at the belt, and it seems to me to be really tight, too tight. Could this have damaged the alternator/pump or something? What would be consistent with that and a rattle that stops above tickover?
It's not coming from the head, definitely around the front, and it's not a timing chain rattle.
Help please?

[mgcjag]

Hi Malcom i dont think a tight belt would have done any damage in a drive back from a service....your in the best position to work out where the rattle is comming from....just lift the bonnet start it up and try to pinpoint it....after a service...could be a spanner or nut/bolt left lying around somewhere...I assume hes changed the coolant...probably pulled the bottom rad hose...check out the clamps......Steve

[malcolm]

I will do Steve - I was waiting for it to cool down a bit before I got looking.

[christopher storey]

Malcolm : to some extent it depends on whether you have a spring loaded jockey pulley tensioner, or whether someone has removed it . If the tensioner is still there these are often noisy because the bearings gradually get worn, and altering the belt tension may have affected matters . The pulley is not all that difficult to test in situ : use a lever to move the arm against the spring , and then spin the pulley by hand

Apart from that, there are the other matters Steve has mentioned

[malcolm]

Thanks Christopher, will do

[politeperson]

If nothing is obvious then it is worth investigating because it could be a loud timing chain.

Why dont you slacken or remove both belts. Then you can isolate an external bearing.

If the rattle persists it could well be a slack chain, especially if it is heard at tick-over.

I have had this happen to me. John, my engineer heard it when I visited him once.

No sooner had he mentioned it he has undone the 4 bolts for the engine breather cover and wound the tensioner on a bit and put it all back together. The chain had been incorrectly adjusted, that was all.

That was it , rattle gone.

[malcolm]

Thanks James, but it sounds almost like something touching a fan blade or the alternator blades. Not checked again yet because I woke up with a foul virus inherited from my Grandaughter. I'll take a look at the weekend provided I'm still alive. I'll try taking belts off and see which stops the noise.