Scotland North AR Posted November 13, 2019 Share Posted November 13, 2019 Evening all, very irritating problem on 2009 150 Sigma SV, circa 60,000 miles.The engine started rattling, take the alternator belt off and it stops. Changed belt tensioner for new one, also the idler below the cams, water pump changed, had alternator sent away stripped and checked, all ok.Feedback from alternator person was that the belt was worn. This belt had done 11,000 miles since change. Belt changed also.The only thing which is now 60,000 miles old is the damped crankshaft pulley. Brief inspection with light on mirror on a stick didn't seem to show the rubber perishing or damaged in any way when looking from the engine side towards the nose.I'll be getting another pulley to try but any other thoughts from anyone as to further checks I should do or possible causes?The belt wear may be an indication that something is not entirely right with the crankshaft pulley?Answers on a post card to.,,, Link to comment Share on other sites More sharing options...
Jonathan Kay Posted November 13, 2019 Share Posted November 13, 2019 Alternator bracket OK?Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted November 13, 2019 Share Posted November 13, 2019 Are the alternator belt pulleys in line ? Link to comment Share on other sites More sharing options...
Sooty Posted November 13, 2019 Share Posted November 13, 2019 Alternator bearings? Link to comment Share on other sites More sharing options...
Scotland North AR Posted November 13, 2019 Author Share Posted November 13, 2019 Thanks, pulleys in line, brackets fine and tight. Alternator bearings checked at strip down. I did initially think it was alternator bearings hence sending it off. The alternator is only 11,000 miles old. Link to comment Share on other sites More sharing options...
Jonathan Kay Posted November 13, 2019 Share Posted November 13, 2019 Try localising the sound with a stethoscope, either commercial or DIY? Usual precautions.Jonathan Link to comment Share on other sites More sharing options...
Tom_Arundel Posted November 13, 2019 Share Posted November 13, 2019 Describe the rattle in detail! e.g. rattle, bang, buzz, constant, intermittent, all speeds, metalic, tinny, thumpy, loud, soft, high / low frequency, front or rear or top or bottom of engine etc., etc..It`ll give you something to do in the wet and windy, dark, north ! Link to comment Share on other sites More sharing options...
Scotland North AR Posted November 13, 2019 Author Share Posted November 13, 2019 It's as if the alternator was loose and therefore a lower frequency rattle rather than a buzz. Just listened at engine idle rather than other speeds.metallic rattle at the front of the engine, nothing near cam cover for example. Link to comment Share on other sites More sharing options...
Ivaan Posted November 14, 2019 Share Posted November 14, 2019 The alternator fan blade isn't loose? Link to comment Share on other sites More sharing options...
Eccles Posted November 14, 2019 Share Posted November 14, 2019 I had something that sounds similar (same Sigma engine), turned out to be the alternator belt tensioner. Looking at it I think the plastic pulley came loose on its bearing.Ivan Link to comment Share on other sites More sharing options...
Tom_Arundel Posted November 14, 2019 Share Posted November 14, 2019 I presume the bottom alternator bolt is in and tight (it`s out of sight below)tensioner pulley is suspect but not noisy...had to make an aluminium replacement several years ago Link to comment Share on other sites More sharing options...
Jonathan Kay Posted November 14, 2019 Share Posted November 14, 2019 I presume the bottom alternator bolt is in and tight (it`s out of sight below)Good point. I'd included that in "bracket" but did you, Nigel?Jonathan Link to comment Share on other sites More sharing options...
Scotland North AR Posted November 15, 2019 Author Share Posted November 15, 2019 Morning, tried all of the above. Had car up on stands, checked everywhere with mirrors and lights, straight edge across pulleys. Checked tightness of everything. Am now borrowing another alternator, trying that, then change the crankshaft pulley/damper.....and after that....Thanks for the advice to date, will update mid next week when I've done the above. Very pleased it's not mid season! Link to comment Share on other sites More sharing options...
Tazio Posted November 15, 2019 Share Posted November 15, 2019 I presume the plug cover isn't rattling? Link to comment Share on other sites More sharing options...
Tom_Arundel Posted November 17, 2019 Share Posted November 17, 2019 Did you ever find out what caused the rattle? Link to comment Share on other sites More sharing options...
Scotland North AR Posted November 18, 2019 Author Share Posted November 18, 2019 Morning, another crank damper pulley arrived today, borrowed alternator hopefully tomorrow, expect to find out where I'm at by Thursday......without a rattle I would hope! Link to comment Share on other sites More sharing options...
Ivaan Posted November 18, 2019 Share Posted November 18, 2019 Don't worry, the rattle will stop when it falls off. Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted November 18, 2019 Area Representative Share Posted November 18, 2019 Could it be anything to do with the cam drive belt & tensioner? Link to comment Share on other sites More sharing options...
Jonathan Kay Posted November 18, 2019 Share Posted November 18, 2019 Any chance of listening with a stethoscope before you start the surgery?Jonathan Link to comment Share on other sites More sharing options...
Tom_Arundel Posted November 23, 2019 Share Posted November 23, 2019 And? Link to comment Share on other sites More sharing options...
Scotland North AR Posted November 24, 2019 Author Share Posted November 24, 2019 .......and......The story so far: -alternator belt tensioner and pulley assembly changedcentral idler changedalternator belt changedalternator pulley found to be worn down from 55 mm diameter to 53 mm diameter at the top of the grooves when compared to new pulley. The peaks of the teeth seem to have worn down after 11,000 miles. Changed the pulley and refitted existing alternator. Alternator is a small WOSP unit.Checked all of the bolts.Still rattling with the alternator drive belt on when running, quiet with the belt off!Tomorrow a new crankshaft pulley goes on!Can't help but think it will be something embarrassingly simple after all of that :( Link to comment Share on other sites More sharing options...
SM25T Posted November 24, 2019 Share Posted November 24, 2019 Can you post a video for us to listen to ? Link to comment Share on other sites More sharing options...
David aka Blue7 Posted November 24, 2019 Share Posted November 24, 2019 >>Can you post a video for us to listen to ?OMG ... TV and radio entertainment must be lousy in Kent? Link to comment Share on other sites More sharing options...
SM25T Posted November 24, 2019 Share Posted November 24, 2019 We cant help hm by guessing ... or watching tv ! Link to comment Share on other sites More sharing options...
Tom_Arundel Posted November 24, 2019 Share Posted November 24, 2019 Beware!!! Not easy to fit a new crank pulley as it is not keyed and it holds the cam timing in place...big risk of moving timing!also crank bolt is `mega` tight as it is only friction that drives the cams,pumps, alternator etc. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now