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w116 visco fans

Started by Big_Richard, 19 November 2011, 07:09 PM

koan

Quote from: s class on 21 November 2011, 03:27 AM
Myth or not, the 3 6.9's I've worked on all had loose head bolts.

Your sample size of three is three times bigger than mine so there's probably some truth in it.

koan
Boogity, Boogity, Boogity, Amen!

s class

Quote from: Major Tom 6.9 on 21 November 2011, 05:53 AM
this is the kind of talk that got me so very concerned in the first place  8)

maybe I will try koans suggestion and inspect them to 80% of the book listed torque.

I don't think you can go wrong with that.  I tightened mine up in the specified bolt tightening sequence. 

My red 6,9 was the least bad of the three - but then I know the heads had been off at least once before in its life. 

On a related topic, my 280SE daily driver started displaying symptoms of exhaust gas in the coolant a few months ago, and I optimistically thought I would check the head bolts.  Found them all to be rock solid.  It is now leaking properly, so a full-on engine rebuild looks to be coming up sooner than I thought. 


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

pompy

The visco fan should roar when starting up cold as well.
The visco on my '76 450 SE 307 000kms works perfectly still - and its just come out of 8 yrs of hibernation.
I doubt it had ever been replaced.
Strange though that it still works as intended.
Last week I did some some stop-start town driving in 33deg C heat for around 4 hrs and the temp guage stuck to 80 deg - rock solid.
I could hear the visco fan continuously doing its job.
Very satisfying.
Even the visco fan on my '91 500 SE (W126) with 120 000kms works perfectly as it should.
That said the one on our '91 300 E was as dead as a dodo at 169 000kms (14 yrs) already. There is no resistance hot or cold, causing temp to quickly climb to 100 deg C in traffic.
I think many people don't realise the importance of a funtional visco fan.

TJ 450

I thought the 300 had the electronic fan clutch like the M102 in the W201? I could be wrong of course.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

pompy

I'm not sure.
I booked it in at a specialist last week to have it replaced and I was quoted R1 200 for the 'fan cluctch'.
What is that - less than 200 Aus dollars?
Oh, and it is genuine Benz part

s class

THe M103's I've seen all have a conventional visco clutch.  Its possible that was changed towards the end of the run though. 


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

goldacre

I replaced my Visco when re doing the cooling system.

Two types - Hella made in China (that's the one i got) and the Borg Warner (unknown manufacture origin) with both pricy at above US$200.

My reading (W116 Library info) was when warmed up the visco will become relatively stiff giving the fan some bite up to 3000-3100rpm. Above that it lets go and spins freely to save fuel when fanging along regardless of temperature.

G
12/1979 450 SEL 148K on clock (museum piece)
12/1986 Lotus Esprit Turbo 87K on clock 'Darling, look what Q has brought for us, isn't it nice' :)