'95 W124 E280 Overheating

[balge59]

The visco fan relies on the stream of hot air through the rad, when the rads get blocked the fans often will not cut in, they all cut in at just over 85c around the same time as the thermostat opens, you can hear the audible click as they cut in

Not on mine, its driving all the time. And no clicks at all! - nothing much in there to click?

230TE electric fan cuts in at about 95ish with a roar but not the visco. Hence wondering about the bi-metal strip.

 

[television]

Not on mine, its driving all the time. And no clicks at all! - nothing much in there to click?

230TE electric fan cuts in at about 95ish with a roar but not the visco. Hence wondering about the bi-metal strip.

Then test with a cold engine and a carrot,, when below 70c feeding a carrot into the blades should stop the blades from rotating, at 90c it should chop the carrot.

All engine electric fans cut in at about 95 to100c all electric rad fans cut in at 100c

 

[balge59]

Then test with a cold engine and a carrot,, when below 70c feeding a carrot into the blades should stop the blades from rotating, at 90c it should chop the carrot.

All engine electric fans cut in at about 95 to100c all electric rad fans cut in at 100c

My visco will shred a carrot from stone cold at tickover (especially now the idle speed correction works! ). Electric fan on the 230 you don't need a carrot, the volume of noise and draught generated when it cuts in is pretty obvious!

 

[television]

My visco will shred a carrot from stone cold at tickover (especially now the idle speed correction works! ). Electric fan on the 230 you don't need a carrot, the volume of noise and draught generated when it cuts in is pretty obvious!

Then you need a new visco unit

 

[kth286]

definitive answer re switching points in 124 cooling system as follows (from Merc workshop manual):

1. engine thermostat starts opening at 85 - 89 and is fully open at 102 centigrade.


2. viscous fan clutch cut-in temp 96 - 104.

there should be a roar as the fan cuts in.

as you rev the engine above approx 4500 the roar should stop as the fan should de-couple for safety; and cut in again as the engine revs drop.

 

[balge59]

Which is why I am wondering about the chances of adjusting the bi-metallic strip to free it off a bit. Or maybe taking it off and lying it flat to drain out some of the silicon?


cheers!

 

[television]

You could lay the strip on a heated surface and watch it, once bent they do not work as the metal has been stressed

 

[WDB124066]

FWIW I have replaced the viscous fan clutch, it was the original factory fitted one - a BEHR. It was replaced with a BEHR, cuts in at 88, 89 on the dash, and won't turn off for at least 2 mins at 84 -85 on the dash. Very annoying as it makes the fan very loud and sucks a noticeable amount of power. In summer in town it won’t turn off, Grrrrrr. Is it possible to get the wrong temp range on a replacement clutch - or is that unlikely??

The original one had a red centre label with 95 (amongst other markings) on it. Could be the year of manufacture or could be the engage temp??