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slight smell of burning

Posted: Sun Jul 22, 2012 3:16 pm
by downward dog
Hi,
Just back from a week in sunny Somerset......scaling a long Exmoor hill, near the very top I noticed a smell of burning, this was, I reckon, just about when the 'fan' kicks in. To clarify....this would be the engine fan would it,rather than the fan that runs when the a/c is operating ?....that big one just in front of the engine?...if i am correct, is there any way that fan can be run to test it and the wiring ? (there is no burning smell on normal steep hills, but this one was a big'un!).

Re: slight smell of burning

Posted: Sun Jul 22, 2012 4:07 pm
by daveblueozzie
What you might have heard was the scavenger fan kicking in, this cools the engine if it starts to get hot under your seats, this may have been the cause of the slight smell of burning.
The scavenger fan is underneath the engine ( not the one behind the radiator) and this fan kicks in when the temp rises via a temp sensor that is under the centre console near the handbrake.

Re: slight smell of burning

Posted: Sun Jul 22, 2012 4:24 pm
by downward dog
Thanks!, I will short the sensor (I have searched 'scavenger fan test', and found a post from Helen and Tony on how to do this) and see what happens!

Re: slight smell of burning

Posted: Sun Jul 22, 2012 5:53 pm
by helen&tony
Hi
If you've got a good "salon" style hairdryer, play the dryer directly against the sensor for a while with the ignition on, and that sets it off...that way you test the sensor at the same time!
It's rather unusual for the scavenger to go off unless you're in very hot weather in a traffic jam, as just a small amount of forward motion is usually enough to clear the engine compartment of heat!
Cheers
Helen

Re: slight smell of burning

Posted: Sun Jul 22, 2012 11:03 pm
by Driver+Passengers
downward dog wrote:...I noticed a smell of burning, ...
My wife's nose detected something a couple of days ago.

250 miles later it turned out that I hadn't replaced the oil filler cap after topping up. I assume you've checked that, already. ;) :lol:

It might be a temperature related smell rather than anything to do with the scavenger fan - if I understand correctly you'd be unlikely to ever hear that fan come on unless stationary - worth checking that it works, of course. Looking elsewhere, is there much oil on or around the turbo? Is the baffle under the bonnet for the blower intake set correctly? Check the front section of your exhaust for cracks, esp up near the manifold.

Matt

Re: slight smell of burning

Posted: Sun Jul 22, 2012 11:23 pm
by Northern Bongolow
manifold stud ??

Re: slight smell of burning

Posted: Sun Jul 22, 2012 11:28 pm
by teenmal
Does it smell like an auld motor bike after a wee skelp up the road.

IE the smell of a Hot Engine.

Re: slight smell of burning

Posted: Tue Jul 24, 2012 11:27 am
by downward dog
Thanks for the extra pointers, I have good a good (abiet slightly large) nose!, I am the one always assigned to smell the milk!!....deffo scorch/burn, not hot engine....it always smells hot! My 'normal' temp reading is pretty high, and as it just clips the red then the Mason alarm is set to warble (set at 4)...very soon after this the temp goes well down very quickly...I assume this is when the scavenger fan comes on....it was between the warble and the temp drop that I got the smell of scorch/burn. I have not plucked up the courage yet to short out the fan to try it, but will soon.......and a good look at the manifold studs etc, nice sunny evening job!

Re: slight smell of burning

Posted: Tue Jul 24, 2012 11:56 am
by helen&tony
Hi
As I said...hairdryer almost against the sensor, ignition on , and wait...it'll test the sensor at the same time as the fan!
If it's happening frequently, you may have a bit of an overheating problem....however, if it's infrequent, it's just doing it's job!
As a rough guide, on our Bongo, in the current heat over here (over 40 C.) it only turns the scavenger on infrequently, and only after a good hill, and sitting ticking over for a fair old time...
Cheers
Helen