Radiator fan loud knocking

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chrisw99
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Radiator fan loud knocking

Post by chrisw99 » Fri Aug 16, 2019 8:05 am

I've noticed my radiator fan is knocking quite violently when it shuts down after the engine goes off.
All the blades seem fine, can't see anything physical (from above) that would be causing knocking.

Spinning it by hand it doesn't knock, and 90% of the time it spins very smoothly. 10% of the time it has quite a rough spin by hand wobbling all over the place.

The knock is definitely the fan though, because if i get someone else to shut down the car whilst I'm pressing on the fan assembly it dampens it a lot and I feel the knocking with my hand.

The knock is incredibly loud, about 4 or 5 times whilst the fan spins down.

Any ideas?

The only thread I can find with a similar issue is this one..

https://www.qashqaiforums.co.uk/viewtopic.php?f=29&t=7000&p=59225&hilit=radiator+fan#p59225
Oct 2014 N-tec+, 1.2 dig-T


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calnorth
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Qashqai Model: Mk.2 Qashqai Facelift - J11b (2017–present)

Re: Radiator fan loud knocking

Post by calnorth » Fri Aug 16, 2019 8:58 am

Sounds like worn bearings on spin down and causing blades to run out of true (wobble)...fairly typical power down occurrence.
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chrisw99
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Re: Radiator fan loud knocking

Post by chrisw99 » Fri Aug 16, 2019 9:00 am

calnorth wrote:
Fri Aug 16, 2019 8:58 am
Sounds like worn bearings on spin down and causing blades to run out of true (wobble)...fairly typical power down occurrence.
Full radiator assembly replacement then or can they replace the bearing?

Got a Nissan Ultimate extended warranty, and can't see anything that would mean it wouldn't be covered. Can't be wear and tear at 45,000 miles surely?
Oct 2014 N-tec+, 1.2 dig-T


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calnorth
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Re: Radiator fan loud knocking

Post by calnorth » Fri Aug 16, 2019 9:31 am

If it is the fan:

No change of bearing. Change the fan with its shroud perhaps..yes. See pic which shows the whole fan/shroud that screws to the radiator, so not a complete radiator change.

Might be worth getting the fan/shroud out and inspect first. I have no idea about the quality of this stuff...always expect the worst. If its past the 3 year warranty stuff then the manufacturer won't care...obviously!

s-l1600.jpg

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chrisw99
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Re: Radiator fan loud knocking

Post by chrisw99 » Fri Aug 16, 2019 1:04 pm

Not sure I'm going to be able to get the fan out and have a look at it - according to the service manual it requires removal of the front bumper, draining all the coolant so you can disconnect some pipes that run in front of it, etc... not an easy job.

The fan does spin very smoothly by hand most of the time, the loud knocking seems far too loud to just be the blades/bearing, so I suspect the vibration of the assembly is causing something else to knock against the chassis or something like that. Nothing visible from above, so maybe need to get the engine floor cover off and take a look from below.
Oct 2014 N-tec+, 1.2 dig-T


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calnorth
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Re: Radiator fan loud knocking

Post by calnorth » Fri Aug 16, 2019 1:21 pm

Will be interesting to know what clatters about... thereabouts.

Colin
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chrisw99
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Re: Radiator fan loud knocking

Post by chrisw99 » Mon Aug 19, 2019 7:58 am

Took them 10 seconds to diagnose bearing failure - knocking caused by bearing bits banging around inside the fan.

Covered by extended warranty, so will get a new fan installed later this week.
Oct 2014 N-tec+, 1.2 dig-T


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calnorth
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Re: Radiator fan loud knocking

Post by calnorth » Mon Aug 19, 2019 8:07 am

I suppose that'll be about £400 for something that is very simple and should have been dead simple to get at.
Thankfully unbusy (retired)
Mk2 Qashqai Facelift - J11b (2017–present)
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chrisw99
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Re: Radiator fan loud knocking

Post by chrisw99 » Mon Aug 19, 2019 8:12 am

£300 part + 2.5 hours labour.

At least it means I've got my moneys worth for my £390 extended warranty this year.
Oct 2014 N-tec+, 1.2 dig-T


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calnorth
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Re: Radiator fan loud knocking

Post by calnorth » Mon Aug 19, 2019 11:55 am

Whats the mileage on that car?
Thankfully unbusy (retired)
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