Motor type 'thing' running when driving & when engine off

[TonyW]

Hi all,

Another probably daft question ..... but first .... many thanks to all you more experienced Bongo owners, this forum is hugely useful.

Here goes; we have noticed (it's not hard to miss) a quite strong 'motor noise/vibration/throbbing' (yes I did use the word 'throbbing') starting up when the engine is running. The revs seem to drop a small amount but we still have full power. This often happens when we come to a stop at a roundabout or T-junction.

Also, sometimes when we have come to a stop and turned the ignition off and then back on, perhaps to put up an electric window, this motor noise (not the engine starting) will start up again.

It all feels like it's coming from directly below the drivers seat.

If anyone can make any sense of this ...... well done and again .... I apologise for my mechanical ignorance if this is something blindingly obvious. I'm on a very steep learning curve here

Thanks in advance for your suggestions and help.

Tony.

[g8dhe]

The cooling fans for the Air con radiator come to mind ? Have you tried turning the Air Con ON/OFF to see if that is what you are hearing ? This would be coupled with the Air Con compressor being switched on/off and this will affect the engine speed as the rev's are turned up slightly when its operating.

Otherwise there is the Scavenger fan, but this normally only operates when the engine housing gets hot, if that is coming on/off it might be down to a fault with its sensor.

[ELZE]

When the air-con kicks in it has a significant clunk and a drain on the revs when idling. quite normal really but not so noticeable when popping along the road