What does this mean?

[Birdman]

On the home stretch after two days and five hundred miles, notice a subdued whine of varying pitch, consistent with engine revs. Definitely not there the previous day. In fact, not there five minutes ago. More like a powerful whoosh, really. Sounds rather good, maybe I can patent the sound and sell it? On second thoughts, investigate! Everything looked tickety boo, except for this whirr-whooshing sound (words don't really work too well here) on blipping throttle. Seems to come from the front of the motor. Any idea what might have happened? (Didn't sound like anything lunching on the engine or I'd have called the recovery service.)

 

[Dieselman]

It's not just the fan driving harder due to the viscous coupling getting fully hot on the longer drive is it?

 

[Birdman]

Went out and checked the fan. Even at normal running temperature - 80C - the viscous coupling is solid. The fan is working all the time. Dieselman, you're a diagnostic genius. :bannana:

Checking the fix list from last August's badger collision (£3,000 in repairs) I see the garage replaced the radiator, fan shroud, hose, fan, drive belt, covering, air baffle, and much more. I wonder if the fan is integral with the coupling? If so, it's under warranty. If not, perhaps it should've been replaced too. Any thoughts?

 

[Brian WH]

Went out and checked the fan. Even at normal running temperature - 80C - the viscous coupling is solid. The fan is working all the time. Dieselman, you're a diagnostic genius. :bannana:

Checking the fix list from last August's badger collision (£3,000 in repairs) I see the garage replaced the radiator, fan shroud, hose, fan, drive belt, covering, air baffle, and much more. I wonder if the fan is integral with the coupling? If so, it's under warranty. If not, perhaps it should've been replaced too. Any thoughts?

Should have been replaced after a bump.

 

[Dieselman]

Should have been replaced after a bump.

Difficult to properly ascertain but I agree. If the fan needed replacing then the coupling was possibly damaged as well.

 

[Birdman]

Difficult to properly ascertain but I agree. If the fan needed replacing then the coupling was possibly damaged as well.

I've spoken to the manager and he seems to agree - it should have been replaced when the rest of the front end was fixed.

Interestingly, I now recognise that the fan is cutting in and dropping out for no reason, but mostly runs all the time and makes quite a noise. Interesting thing is that the temperature stabilises at 80C. Why doesn't the engine run cool - does the thermostat restrict coolant circulation if the engine is overcooled by the fan?
Btw anyone know what a replacement viscous coupling £costs these days?

 

[Dieselman]

I've spoken to the manager and he seems to agree - it should have been replaced when the rest of the front end was fixed.

Interestingly, I now recognise that the fan is cutting in and dropping out for no reason, but mostly runs all the time and makes quite a noise. Interesting thing is that the temperature stabilises at 80C. Why doesn't the engine run cool - does the thermostat restrict coolant circulation if the engine is overcooled by the fan?
Btw anyone know what a replacement viscous coupling £costs these days?

The thermostat will control the temperature irrespective of fan operation.

Get the job done under the original claim as a new coupling will be "proper" money.