Saturbo Posted December 22, 2008 Report Share Posted December 22, 2008 Folks, last few days I've been getting a humming noise from the engine bay or dash area. Sounds as if a fan or something is running but no amount of twiddling with knobs etc gets rid of it or even changes the note. Its not rev related so I'm ruling out anything in the engine itself. I can't hear it when I listen with bonnet up from outside. Is there a vacuum pump or anything else could give me these symptoms? Otherwise the car drives fine - just a bit annoying. I also think I'll do my thermostat after Kiwi thread - good post! Link to comment Share on other sites More sharing options...
RJP Posted December 22, 2008 Report Share Posted December 22, 2008 Am I right that you can hear it when the car is not moving? Do you still hear it with the ac off? I have been trying to pin down a single high pitched note that starts after driving for a while, and is unaffected by ac, gear in neutral, steering position, braking etc. but in my case it is definitely only when moving. I suspect a propshaft bearing or CV joint, or maybe a drive shaft bearing, but I have not found it yet. Probably completely different, but the fact that the note does not change whatever happens struck a chord, if that is an appropriate expression... Link to comment Share on other sites More sharing options...
Saturbo Posted December 23, 2008 Author Report Share Posted December 23, 2008 Yeah I can hear this one when the car is stationary. It sometimes gets louder and dies away, but is generally there all the time. I'm wondering if it could be steering pump or something else that is not engine speed related. Anyway I'm off for a few days over Chrimbo so I might get a chance to look the car over Link to comment Share on other sites More sharing options...
sgtstrev Posted December 28, 2008 Report Share Posted December 28, 2008 Hi i have had a problem similiar on most of the A8`s that i have owned and it has either been the fresh air blower or the A/c fan in the engine bay if you select econ on the climate control panel you can shut the fan down to help try and pinpoint the noise. If it is this i have managed to remove the fan and drill a small hole into the back around the bearing area in order to re-pack the bearing using a grease gun which has normally extended the life for at least another 20,000 miles . Another quick way of checking is to wiggle the fan unit itself . but be warned they can start at anytime !!!!!!! best to leave car for a few hours to try and reduce this happening best of luck . A quick squirt of WD-40 on the belts can also help sometimes to pinpoint the area. Link to comment Share on other sites More sharing options...
Saturbo Posted December 29, 2008 Author Report Share Posted December 29, 2008 Hi i have had a problem similiar on most of the A8`s that i have owned and it has either been the fresh air blower or the A/c fan in the engine bay if you select econ on the climate control panel you can shut the fan down to help try and pinpoint the noise. If it is this i have managed to remove the fan and drill a small hole into the back around the bearing area in order to re-pack the bearing using a grease gun which has normally extended the life for at least another 20,000 miles . Another quick way of checking is to wiggle the fan unit itself . but be warned they can start at anytime !!!!!!! best to leave car for a few hours to try and reduce this happening best of luck . A quick squirt of WD-40 on the belts can also help sometimes to pinpoint the area. I've tried selecting Econ and turing all other fans off but noise is still there. The other day I listened around the engine bay while motor was running. Using a long screwdriver as a stethescope the noise seems to be from the bulkhead area under the airfilter housing thing in the middle. Is this the fan you removed to grease up? I'd appreciate if you could point out on a picture what you removed? I'm pretty handy with the spanners etc but just not familiar with these cars yet - I've been a Saab 900 guy for years Link to comment Share on other sites More sharing options...
Ska Posted December 29, 2008 Report Share Posted December 29, 2008 Here's a link to the fan bower repair; audipages Fresh Air Blower Replacement, but I'm not sure it is that that is making the noise. Please note that the "econ" botton disengages the AC compressor clutch and does not switch the blower off, though it may stop the cooling fan in radiator off depending on system pressure/temp. A few posts back someone else had a similar noise on his V8; IT_S8 pointed out that there was a coolant pump or something similar in the same region. Not sure if it exists on V6's but it may be that. Have you placed the screw driver on Throttle body which is also at the back of the engine bay just to eliminate that? Link to comment Share on other sites More sharing options...
Figure11 Posted December 29, 2008 Report Share Posted December 29, 2008 If it is the blower fans here is a how-to on removal and replacement. Click here. Mike Link to comment Share on other sites More sharing options...
Ska Posted December 29, 2008 Report Share Posted December 29, 2008 Beat you to it Mike:p+++ Link to comment Share on other sites More sharing options...
Figure11 Posted December 29, 2008 Report Share Posted December 29, 2008 Beat you to it Mike:p+++ Bugger!! I'd like to say Great Minds and all that, but I would be bragging! . It's the TSN service that counts. Mike Link to comment Share on other sites More sharing options...
Saturbo Posted December 30, 2008 Author Report Share Posted December 30, 2008 I'm not sure it is that that is making the noise. A few posts back someone else had a similar noise on his V8; IT_S8 pointed out that there was a coolant pump or something similar in the same region. Not sure if it exists on V6's but it may be that. Have you placed the screw driver on Throttle body which is also at the back of the engine bay just to eliminate that? The coolant pump sounds as if it might be a contender - last night while driving the blower went cold for about 3 miles and came back again but there was a screech just before this happened. I'm pretty sure its not the fresh air blower as the speed (or noise of the speed) doesn't change. I can put the blower up full blast or off completely and the noise is still there. Throttle body seems to be fine. I'm going to search for IT_S8's post to see what's what thanks for the help so far guys Link to comment Share on other sites More sharing options...
Ska Posted December 30, 2008 Report Share Posted December 30, 2008 if that pump runs dry it'll die! Link to comment Share on other sites More sharing options...
zipzz1 Posted April 27, 2011 Report Share Posted April 27, 2011 Hi Saturbo I seem to hear the same annoying humming noise that you mention. Did you find out what was causing it? It sounds like an empty running pump just behind the driver side dashboard - and the noise doesnt change Ac/No AC, revving up, stationary or moving. I can hear it from outside if I listen carefully? What is located in the engine bay in the approximate area? Zip Link to comment Share on other sites More sharing options...
Saturbo Posted April 27, 2011 Author Report Share Posted April 27, 2011 Hi SaturboI seem to hear the same annoying humming noise that you mention. Did you find out what was causing it? It sounds like an empty running pump just behind the driver side dashboard - and the noise doesnt change Ac/No AC, revving up, stationary or moving. I can hear it from outside if I listen carefully? What is located in the engine bay in the approximate area? Zip It was the auxilliary heater pump which is located up near the passenger side of the heater air intake. The solution I used was to unplug the pump = no noise. Link to comment Share on other sites More sharing options...
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