Viscous fan clutch -overcooling?

[balge59]

Hi
bit confused about my 300TD cooling.... never had a Diesel before so not sure what's normal!
Car seems to take forever to warm up compared to my 230TE!
Tested the coolant sensor, seems fine so I'm going to replace the thermostat, although apparently it was replaced a couple of years back - do they commonly pack up so soon? - only had to do it once in 5 years on the 230....
BUT - regarding the fan clutch - I got a bit more confused than usual. Cold start (warm day tho) engine ticking over, tried the 'carrot test' (with a stick - no vegetables were harmed in the making of this post!) and it ripped it out my hand - ??? On the 230TE the fan only cut in when the engine was fully warm (sounds like a 'plane going over) but this roars all the time. Mate looked at it said that's right - as long as it moves with the engine stopped, well it does, its not 'free', but you can push it round ok - 230 spins freely at rest?
Anyway the point is - is the fan clutch adjustable via the bi-metallic strip or is it worth trying to drain of some of the 'oil' in it?
(assuming the thermostat doesn't sort it out)

 

[television]

Could the engine fan be the electric clutch type,, these have two thin wires running to top of the engine, and one going to the first sensor switch on the top

 

[balge59]

hmm thinking back the 230TE might have been electric - seem to remember changing that sensor switch on it not so long ago. Pretty sure the 300 is viscous though, finned hub, bi-metallic strip on front?

 

[television]

I have a feeling that they may look the same,, but in answer to the question the visco fans are not adjustable

 

[balge59]

I have a feeling that they may look the same,, but in answer to the question the visco fans are not adjustable

ok cheers for that...how about the movement, how free is free, as it were?
should it spin freely or just barely?
Do Diesels take forever to warm up?


just found this http://www.peachparts.com/shopforum/showthread.php?t=195595
hmmmmm...

 

[television]

There spin fairly free, but not as though it was just a bearing on a shaft. you can push it round, its as though it on a rubber mounting

Diesels do take longer to warm up with many in the winter months never getting up to the correct temp when the thermostat is a little bit iffy

 

[ncooper]

ok cheers for that...how about the movement, how free is free, as it were?
should it spin freely or just barely?
Do Diesels take forever to warm up?

A viscous fan will not spin freely,only when you push it,the version with a clutch will spin freely and be fixed,ie no fingers or carrots,when engaged.

Diesels do take longer to warm up,as they are more efficient than petrol engines,there is much less waste heat.

Most diesels,when ticking over at a standstill, will actually cool off,whereas a petrol engine will get hotter and hotter.


Having said that,there should not be a really loud roar when you rev the engine,so perhaps your viscous fan is not working correctly.

So long as it does come up to temperature eventually,I would leave well alone or at least go no further than a new thermostat.

Regards,
Nick.

 

[balge59]

hmm ok, might be dragging a little, but it certainly moves... it moves when pushed but doesn't 'spin on' at all...might be on it's way out.
Cheers to all for the tips, , I will keep an eye on it after I get the thermostat done over the w/e but 'Don't Panic'! eh?

 

[television]

hmm ok, might be dragging a little, but it certainly moves... it moves when pushed but doesn't 'spin on' at all...might be on it's way out.
Cheers to all for the tips, , I will keep an eye on it after I get the thermostat done over the w/e but 'Don't Panic'! eh?

N coopers post was better than mine,you cannot make it spin,, it feels as though it is rubber coupled, but is does turn

 

[dieselman]

You should be able to feel the amount of air being pushed through the fan into the engine bay. With the engine cool it should only be a draught, with it very hot it will be a gale.

As said diesels do tale longer to warm but MB diesels are pretty quick.

Unless you are thinking of towing a caravan across the Sahara I'd just take the fan blades off and see what happens.

 

[balge59]

Well... definitely more gale than a draught...even from a cold start its definitely moving well.

"Unless you are thinking of towing a caravan across the Sahara I'd just take the fan blades off and see what happens."

- for sure? - might leave that til winter - my god Diesels are weird....

 

[dieselman]

- for sure? - might leave that til winter - my god Diesels are weird....

It won't over heat without the fan. Mines been missing in action for two or three years now.

 

[balge59]

It won't over heat without the fan. Mines been missing in action for two or three years now.

OK...I'll bear that in mind come winter if the thermostat doesn't sort it out!

cheers!

 

[balge59]

Just fitted a new thermostat - didn't have one fitted!
See how that helps eh?
I'm starting to worry about this car...

 

[Naraic]

No stat??? Wow. It should go better now.

 

[balge59]

No stat??? Wow. It should go better now.

got to hope so! Seems better already, still making sure the coolants settled down and no leaks, but it seemed to warm up noticeably better than without one!!