Roaring sound going with the revs

[FerdiNL]

Morning guys,

Since a day or 2 the 3 litre is making an extra sound while climbing the revs.
First it started going ocasionaly, but now it is constant and starting to get anoying.
Best way to discribe it is like a big V8 diesel. This morning on my way to work I made a short video:

https://www.youtube.com/watch?v=qKlpvw3y6Gg

Do you guys have any idea what it could be?
I've noticed the fan isn't smooth to turn with the engine turned off, but no idea if this is normal.
No lights burning and performance isn't affected as well.

This saturday I finally do have some time to put the truck in the shed so really want to solve it then.

 

[jims-terrano]

Actually sounds just like my old 3 litre and I do miss it a hell of a lot. It does sound like the viscous fan, wonder if the oil inside the coupling has thickened because of the cold weather.

Wonder if her indoors will let me have another 3 litre:naughty

 

[FerdiNL]

But the oil should warm up after more then 30 miles or doesn't that make a difference?
In the previous winters it didn't made this sound.

The 3 litre is a great engine, as far as my history with 4 cilinder diesels goes this is the one I prefer te most

 

[jims-terrano]

I don’t know if it would heat up the same in cold weather, probably would need to be a lot colder than normal I suppose. The coupling is pretty much at front of engine and getting cold air blown at it all the time. Of course may just be the coupling end of life and if fan is now running all the time is that increasing the fuel consumption too?

 

[FerdiNL]

That is a good point. Maybe gonna trying to heat it when the truck is in the shed and see what happens.
I think consumption is up a bit, but not completely sure.
The engine does heat up as quickly as it always does.

After 16 years the coupling could be worn out.
When the engine is turned off is it normal that the fan has much resistance or should I be able to turn it freely?

 

[solarman216]

Summer or winter, hot or cold when you first start the engine rev it to around 3k and it should roar, it varies as to how long but if it is still roaring after about 3 minutes your viscous coupling is goosed, on the 2.7 you have to replace the water pump but do not know on the 3 . Rick

 

[Banshee]

This happened to my Maverick and it went when I swapped the water pump :thumb2

 

[FerdiNL]

Summer or winter, hot or cold when you first start the engine rev it to around 3k and it should roar, it varies as to how long but if it is still roaring after about 3 minutes your viscous coupling is goosed, on the 2.7 you have to replace the water pump but do not know on the 3 . Rick

Thinking about this, with a working coupling the fan should stop turning when the right temperature is reached?
Because I've never seen my fan doing this, it is always turning and never standing still with a running engine.

On the 3 litre the coupling can be swapped as far as I know.

Thinking about Banshees post about the water pump, that one is chain driven?
If so, is it possible to remove the fanbelt and see what happens?
Because if the coupling is broken the sound will be gone, if the pump is faulty it should be still there.

Also when the sound did start it wasn't always going with the engine rpm's, that became a little later.
Just remembering that.

 

[solarman216]

Thinking about this, with a working coupling the fan should stop turning when the right temperature is reached?
Because I've never seen my fan doing this, it is always turning and never standing still with a running engine. .

The fan never stops, at start up the viscous fluid was laying at the bottom in a lump once spinning it is redistributed within the coupling and the fan is no longer directly driven but still spins, as the radiator heats up the bi-metallic coil spring on the front senses the hot air and turns to open a valve allowing the fluid to drive the fan at almost full speed, so cooling the rad, worth checking that the pin in the middle is free and not seized, if it is and you can free it off then job sorted, other than that a new coupling, Rick

 

[Banshee]

The fan never stops, at start up the viscous fluid was laying at the bottom in a lump once spinning it is redistributed within the coupling and the fan is no longer directly driven but still spins, as the radiator heats up the bi-metallic coil spring on the front senses the hot air and turns to open a valve allowing the fluid to drive the fan at almost full speed, so cooling the rad, worth checking that the pin in the middle is free and not seized, if it is and you can free it off then job sorted, other than that a new coupling, Rick

That a TOP explanation Rick :thumb2

 

[FerdiNL]

Superb indeed! :clap

 

[FerdiNL]

Got things moving again!

Had to remove the radiator, and the fan but after a bit of grease and moving stuff around it started to come loose again.
We will see how long stuff will keep on going, if it fails again I'm also thinking about replacing it with a bit more modern cooling.

 

[micktheshed]

In anything but hot weather or towing I find I don't need a fan at all. The original fan was removed due to collision damage & I replaced it with an electric (Kenlow) fan as this was cheaper (& more efficient). This very seldom comes on even when towing 1.6T caravan in the summer, & has the advantage of manual operation, in anticipation, if needed.

The original fan made a lot more noise than the electric one does, have you tried just removing the fan itself as a test?

In case you're interested The electric fan just fits in front of the rad, behind the downward central strengthening pillar. This necessitated removing the viscous coupling (which was broken anyway!) & teasing out the pillar, together with elongating the rad bracket holes. Easy job.

BTW: There is room for the fan to fit behind the rad when both original fan & viscous coupling are removed. Don't think they are separate items on the 3L.

 

[FerdiNL]

Thanks for the info!
What size fan are you using? The sound is starting to come back so I'm thinking of removing the fan next week or so to test of the sound is gone.
Was searching today about fitting an electric instead if the viscous one since this is cheaper and more silent.

 

[micktheshed]

Thanks for the info!
What size fan are you using? The sound is starting to come back so I'm thinking of removing the fan next week or so to test of the sound is gone.
Was searching today about fitting an electric instead if the viscous one since this is cheaper and more silent.

If removing the fan does not cure the noise then suspect the water pump (or ancillary) bearings.
The electric fan I have is 17" (432mm) outside dia. Kenlowe ref: 17.HP.B/S 12V & has both adjustable thermostatic & manual operation. It is an easy fitment.
If you do fit this fan it is advisable to have it in front of the rad to allow better access room for servicing the drive belt & water pump etc., which can be even more improved by leaving off the redundant top fan cowling, this will also allow the easy re-fitting of the viscous fan if it is ever needed in the future.
Good luck!

 

[FerdiNL]

Thanks again! I will have a look as soon as possible.
Hoping it still is the viscous coupling so it's gonna be an easy Fox and in nu eyes a small ugrade as well.

 

[FerdiNL]

Just ordered a 16 inch electric coolingfan from Monster Cooling.
Kenlowe doesn't produce any more for the aftermarket do had to seek a fan strong and small enough to make it work.

Only thing now is waiting because they ship it from the States.