2.8 V6 viscous fan and slight thudding noise

[S4_dan]

Hi guys,

car sounds like a constant airplane. From 1st thing in the morning to the last thing at night. Should the viscous fan run continuous and sound loud?

The engine gets upto temp fine and runs constantly at 90c. Just the noise I'm not keen on.

Also, only does this in 1st gear when setting off but there is a concession of 3 thuds/judders from rear (diff?) when setting off then its fine through the rest of the gears until i stop again.

Any pointers please?

Cheers,

Dan

 

[audiv8quattro]

Hi mate I have the little brother to your car the 2.6 v6 quattro and unfortionatly yes the fan does run constantly as it's belt driven and not electric, after searching and speaking to many people on different forums I changed my fan to an electric fan done away with the viscous fan pulley altogether and brought a smaller belt it doesn't sound like an airshow now and frees up abit of power to the engine regarding other problem I'm not sure mate sorry

 

[audiv8quattro]

If you look about halfway down the thread page you will see a thread about viscous fan and rad broken that might be of some use aragorn and byzon a4 were very helpfull. Hope this helps aswell

 

[aragorn]

It shouldn't be audible.

It runs all the time, but the viscous coupling should only "lock up" when the engine gets hot (>~100c)

If it sounds like a plane the viscous coupling has seized.

 

[aragorn]

Also the thudding is potentially the rear diff mounts, but i fitted stiff mounts to mine and the thudding turned into a clank, and on closer inspection its play in the diff itself.

I guess trying some new mounts cant hurt, and they're not THAT expensive.

The rear ones are 8A0599257, you require two and they're a tenner each.

The front one i've simply removed and filled with polyurethane sealant to stiffen it up.

 

[audiv8quattro]

I went through 3 of the they all shattered on me f***ing things and all mine were noisy if I would have known they wasn't meant to be heard I wouldn't have spent money converting to an electric fan lol oh well

 

[S4_dan]

Also the thudding is potentially the rear diff mounts, but i fitted stiff mounts to mine and the thudding turned into a clank, and on closer inspection its play in the diff itself.

I guess trying some new mounts cant hurt, and they're not THAT expensive.

The rear ones are 8A0599257, you require two and they're a tenner each.

The front one i've simply removed and filled with polyurethane sealant to stiffen it up.

Thanks for that. Will get some next week and try them.

Any ideas on how much a viscous unit would be?

Cheers.

 

[audiv8quattro]

Well I picked up a viscous fan coupling and blade from partsgateway.com for £30 a couple of months ago so you could try them it makes it easier if you have part number mine was 078 121 350 but not sure about yours it should be located on the front of the viscous coupling on a metal plate. You could also try eBay or 247spares.com

 

[audiv8quattro]

Just found this on eBay,try that VW PASSAT VISCOUS FAN CLUTCH 078121350A 078 121 350 A | eBay UK
And it is the same part for the 2.8 and the 2.6

 

[Bradderz_1988]

I had a thud from the rear on mine turned out after a bit of hard driving the 3 hex bolts on the rear diff mount came loose bit of loctite and jobs a good un !!