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| 22900013A Member Since: 23 Dec 2010 Location: Oxfordshire Posts: 3150   
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Is my aircon supposed to sound like this? Never noticed it before in nine years of ownership!
Any ideas? It goes off if I turn the aircon off. 2011 110 USW 1973 Series III 1-Ton 1972 Series III 1-Ton Cherrypicker 1969 IIA 1-Ton 1966 IIA 88" |
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16th Jan 2021 11:41am |
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cheers Paul| 22900013A Member Since: 23 Dec 2010 Location: Oxfordshire Posts: 3150
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I'm not sure how I would tell if it cuts out when running (ie getting airflow) as I can't hear anything over the engine. Is the fan supposed to kick in when aircon is running when the vehicle is stationary? 2011 110 USW
1973 Series III 1-Ton 1972 Series III 1-Ton Cherrypicker 1969 IIA 1-Ton 1966 IIA 88" |
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16th Jan 2021 12:07pm |
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| Matt110 Member Since: 29 Jun 2014 Location: UK Posts: 685
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Mines that noisy.
I'd suggest there's nothing wrong with it. But it won't like running with a fan cover in place or even a small gap as per the video as the air flow will drop so significantly that it'll starve the fan bearings of any air to cool them. That's a pretty long term failure mode but they're not designed to run in stagnant air. The fan will also be "cavitating" more (not sure if that's the gas version of the marine term) as it's technically generating a much lower pressure on the suck side than the blades are designed to do... Thus the blades get noisier. Can't for the life of me remember much of my uni Fluid Mechanics however haha. The fan kicks in based on the pressure in the system. If there's not enough cooling available and the condenser panel temperature rises, the fan kicks in. As the temperature of the condenser panel drops, the fan goes off again. You can see this in that in a puma system without any radiator muff, the fan will constantly trip in and out when the vehicle is stationary idling in medium temperature weather. If yours is running permanently stationary, it's not getting enough air or the system is overcharged. |
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16th Jan 2021 2:42pm |
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| 22900013A Member Since: 23 Dec 2010 Location: Oxfordshire Posts: 3150
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I've known the main cooling fan kick in sometimes, usually just for a few seconds. Is the aircon fan different? I only had it on to try and help with demisting. 2011 110 USW
1973 Series III 1-Ton 1972 Series III 1-Ton Cherrypicker 1969 IIA 1-Ton 1966 IIA 88" |
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16th Jan 2021 2:52pm |
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| Matt110 Member Since: 29 Jun 2014 Location: UK Posts: 685
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The main engine fan is thermoviscous and connected directly to the engine and is driven by the engines rotation. When the block heats up the coupling engages till the temperature comes down again. Normally comes on after you've sat on a motorway for 20 minutes, pull over to a dead stop at a junction and then go to pull away again. It runs because the engines working hard and stable thermally at speed because the radiator balances out the energy going in from the fuel. But as you stop, the heat is still soaking into the coolant from the motorway travel, but you've lost host the engine revs (reducing the number of coolin cycles through the engine and radiator), and the radiator cooling as a result of the speed you were travelling at.
It's completely separate to the air conditioning fan which you show in the video. Which isn't fitted unless you have air con, and doesn't ever work unless the air con is running. (I think..... Unless the vehicle has an override somewhere to turn it on at very high ambients). |
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16th Jan 2021 3:31pm |
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| HardCharger Member Since: 03 Mar 2013 Location: Manila Posts: 744  
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That sounds normal. The aux fan really comes on when you turn on the AC and after a while it will cycle. The cycling interval is not that long so it'll seem like it comes on not long after it cycled off.
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18th Jan 2021 5:31am |
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| Vitesse Member Since: 21 Mar 2014 Location: Sussex Posts: 388 
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My aircon is making an awful noise. The fault is a failed bearing in the aircon fan. I need to replace in due course.
Sounds similar to your noise in the video. Hope this helps? 2015 90 XS Santorini Black |
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19th Jan 2021 11:14am |
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