Scirocco Central

After a 30 minute drive without stopping or starting and the car was driven quite hard I pulled up at my house and let the engine cool down at idle for around 2-3minutes.
I heard an unusual kind of droning noise. It didn't seem like a normal fan sound and was like a whirring/droning/humming noise coming in waves.

It may well have been the fan but it certainly didn't sound like a fan I've heard before lol.

Also...

As the car has got a forge dump valve on it (last owner installed) I'm thinking it may well be not functioning correctly. When I lift my foot off the accelerator quickly I get the initial loud psst sound followed by a quieter prolonged hissing.
Would this likely be the valve itself or a leak somewhere ?

Your suggestions would be appreciated.

Thanks

The sound could be the auxillary water pump which is electric and runs under certain conditions and more noticable sometimes when you switch the engine off and it continues running for a short time to keep the coolant circulating to prevent heatsoak after the mechanical pump has stopped.

Sorry can't help with the dump valve.

Hi. I totally agree with cuprabob. I had the same problem last year. Once changed timing belt and water pump never happened again. And as gorvthe dump valve sounds like it has a sticky diaphram wich can be solved by removing it and cleaning it. Hope it helps

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