W124 Cooling upgrade?

uchiha

Active Member
Joined
Aug 20, 2008
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111
Location
London
Car
1992 500E
I realise there are a few cooling threads running at the moment but I haven't managed to find the answers I'm looking for and was hoping someone on here would be able to offer some advice.

My viscous fan coupling has gone and needs replacing. My engine is running hot and I'm tired of driving around with the heating on/windows open. Having done a little research I have narrowed down the options available.

1) Buy a new coupling - £400 ish. What I've learnt about this is that it uses HP from the engine and although it 'de-couples' at around 3k rpm, it still requires power from the drivetrain. Also, from what I understand, the resistance does not kick in fully until the engine temp is at around 105 degrees, which already too hot.
-In this regard I would be particularly interested in whether or not anyone has fitted an M120 600SL coupling? I understand this has a lower viscosity and comes on earlier?

2) Electric fan. All modern Merc use electric fans. This must be with good reason, but do they move as much air as the old mechanical fans (perhaps twin electric main fans would move more air than mechanical? see option 3..) A possibility is to use the electric system from the W220 or a fan from KENLOWE but I was hoping someone on here had already done the leg work. I would only want to do this if there was a noticeable/proven reduction in running temps. Alternator would need to be upgraded, however.

3) A complete cooling solution i.e. radiator plus bespoke shroud plus fan(s). I think my radiator is due for replacement anyway so although this would be more expensive, it would make sense. I know of companies in the US such as Custom Built Aluminum Radiators - Ron Davis Racing Products who make bespoke items but am not familiar with anything similar in the UK.

Any advice would be much appreciated.
 

grober

MB Master
Joined
Jun 22, 2003
Messages
30,687
Location
Perth, Scotland
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W204 ESTATE
You will find the clutch you need here. Made by Sachs I believe WebCat 3 It should not cost more than about £75 as has been said. High underbonnet temperatures have always been a problem with the big V8s. This guy has a well thought out solution. K6JRF Auto Page

ps a viscous coupling should never be stored flat "on the shelf" -- they must be stored vertical to prevent fluid migrating to the wrong areas of the unit and cause early malfunction.
 
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Will

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Jan 21, 2003
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Surrey
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GL63 AMG / 190E 2.5-16 / Porsche 911
Although I appreciate that the electric fans may be more efficient overall, don't forget that decreased load on the engine due to removal of the mechanical fan will be somewhat replaced with additional load on the engine due to the alternator charging more to due to the additional electrical load.

How many miles/year are on the original fan/coupling? I think for a collectable/rare car like the 500E I'd be inclined to keep it as close to OEM as possible.

Will
 

w124coupe

Active Member
Joined
May 14, 2006
Messages
902
Location
Midlands
Standard cooling works fine in much hotter places than London.

Can we assume you have made sure the cooling system is clean and has the right coolant in? Always worth £25 and a couple of hours work to use a 2-part flush and then fill with the correct fluid. If the rad doesn't survive the flush then it was well on the way to letting you down anyway.

Also well worth pressure washing the rad to remove all the dead flies and making sure not too many of the small fins have been bent over by stones over the years.

Add the standard fan coupling and you should be fine.

Also do you have the two supplementary A/C fans at the front? If they have failed that will make your issues worse with the heat from the A/C exchanger.
 
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uchiha

Active Member
Joined
Aug 20, 2008
Messages
111
Location
London
Car
1992 500E
Thanks,
In light of the responses I will stick with the viscous system.

Regarding prices, perhaps my local MB has it wrong but my tech also mentioned that the part was around the same price - I'll call again on Tuesday.

Okay, the next thing my current fan is an 8 blade aluminium fan. I am considering upgrading to 11 blade fan from M120 engine. The reason for this change is that 11 blades would move more air than 8 blade.

Firstly, is this logic correct and if so, will it be a simple changeover?
 

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