hl1977 Posted October 3, 2015 Share Posted October 3, 2015 I had to drive through several mud/clay holes lately. During that the fan belt started to screech really badly. Actually, it was almost unbearable to stay near the working motor (= extra noisy defender). Apparently there was some dirt splashed on the belt. In local garage they supported the idea, as the working face of pulleys was polished shiny. So I have spent hours to clean pulleys and placed a new belt. Bloody annoying work so thought that maybe there is something to be done to keep the belt clean? Avoiding dirt roads and mud-holes is unfortunately not an option Engine is 300tdi fitted on defender in 1995. Also, could someone give a short tutorial how to remove topic Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 3, 2015 Share Posted October 3, 2015 I suspect your belt was already worn if it was doing that... Quote Link to comment Share on other sites More sharing options...
hl1977 Posted October 3, 2015 Author Share Posted October 3, 2015 I suspect your belt was already worn if it was doing that... Don't think so, as it was OEM belt placed just 7000 km ago. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 3, 2015 Share Posted October 3, 2015 Tensioner OK? Quote Link to comment Share on other sites More sharing options...
Lewis Posted October 3, 2015 Share Posted October 3, 2015 The pulleys will be polished shiny anyway through the normal running of the belt. Check the idler pulley on the front cover, the bearings in these are non replaceable and known to fail Quote Link to comment Share on other sites More sharing options...
Daan Posted October 3, 2015 Share Posted October 3, 2015 Tensioner Is where I'd look first. I've been bonnet deep and it never made bad noises or slip. Daan Quote Link to comment Share on other sites More sharing options...
hl1977 Posted October 13, 2015 Author Share Posted October 13, 2015 I excluded the tensioner, as the whining stops when spraying water on the belt. After it dries out, the whining comes back. I've changed the tensioner with new one without any effect. Only thing that reduced the whining was cleaning pulley grooves from burnt in rubbery material (from belt I assume). Also the grooves of belt itself are damaged, filled with similar rubbery debris as pulley grooves. I'm still waiting for new belt after what I hope the whining stops. My assumption is that during driving through clay/mud holes the mush was splashed to belt. There it was rubbed into belt material and due to increased friction it melted to pulley and belt grooves. So far I had stuck viscous coupling and the fan was working all the time and air flow kept the under-bonnet area clean and I didn't got any problem with belt contamination (heard few days back, that keeping belt clean was also problem for some MB engines back in 1980ties). Anyhow, I have removed the fan in late august (driving became much quieter, no overheating even when towing 2,5 tonne trailer, fuel consumption dropped at least 0,5 l/100km - just wonderful). But there are a lot of splashes under bonnet (on top of coolant tank, on top of engine, etc etc) now. My conclusion is that removing fan, I exposed belt for dirt. But I have no experience with defender with non-stuck viscous coupling, so if I'm wrong please correct me. Quote Link to comment Share on other sites More sharing options...
oneandtwo Posted October 13, 2015 Share Posted October 13, 2015 I have three 300tdi defenders. All have suffered from belt squeak and chirp over the years, usually after not being used for a few months. It is always rubber debris in the belt which causes the noise. - I live by the sea an if not used the pulley surfaces rust and abrade the belt causing the rubber debris. I have tried cleaning the rubber belt grooves but it never really works. I generally do a hundred or so mile on the noisy belts, by which time the rust is all cleaned off the pulleys, fit a new dayco belt and it runs silently. Quote Link to comment Share on other sites More sharing options...
hl1977 Posted October 14, 2015 Author Share Posted October 14, 2015 I have three 300tdi defenders. All have suffered from belt squeak and chirp over the years, usually after not being used for a few months. It is always rubber debris in the belt which causes the noise. - I live by the sea an if not used the pulley surfaces rust and abrade the belt causing the rubber debris. I have tried cleaning the rubber belt grooves but it never really works. I generally do a hundred or so mile on the noisy belts, by which time the rust is all cleaned off the pulleys, fit a new dayco belt and it runs silently. Thanks for reply. I hope that new belt solves the problem of squealing. I have had one absolutely quiet belt so far, and that was 'made in PRC'. But, it broke into pieces after 15000 km / 1 year. I have used also 2 dayco belts and they both had some chirping... Quote Link to comment Share on other sites More sharing options...
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