Towing - Cooling confusion!

Coopergreg

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Hi

I've a W212 2012 E220CDI Automatic Estate , and we're looking to tow a caravan max laden weight of 1500kg (just under the 85% kerbweight). Max towing limit for this car is 2100kg according to the manual.

I'm getting an aftermarket towbar, but asked Merc if any additional cooling was required:

My local dealer put the VIN in their system, and it came up with no parts required in addition to the towbar, electrics and 'adaptor' (assume this is a 7 to 13 pin adaptor?).

However Merc Customer Services Tech reply was that the "cooling fan on your vehicle will need to be checked to see if it is compatible and thusly if any modifications are required" - a nice, vague reply!

If required, my local (excellent) specialist MD Motorcare can fit a 600W fan in place of the existing 400W.

We're not planning any mountainous mediterranean jaunts in 35C heat, but will likely do Lake District / Highlands type trips so any thoughts on if this mod is definitely needed?

Also, is there any warning messages or indication of high transmission fluid temperature on this car? (can't see anything in the manual to say there is).

I've no warranty requirements to fit it (it's a 2012 vehicle).
 

Naraic

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I think this is more about tranny cooling (as you suggest) than engine cooling.

I know in the past these cars (210s not 212s) have had tranny coolers fitted...yours may have one already.
 

keefysher

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I've recently put a towbar on my W221, if I may, I'll give you my rationale:

The main issue is around transmission cooling. Can you afford a new gearbox if you go aftermarket and you overheat the box? Earlier S212 cars required the cooling fan upgrade, as do the BluTec models.

The second issue is the interface with the electronics on your car. The MB kit is plug and play and will give you everything required. Aftermarket may not, despite what the supplier says.

Does your car have the self levelling rear suspension?

There is an OEM towbar available from MB, that is the full monty. Your indie would be able to get this for you at 'trade' plus fitting I would have thought.

I ended up main dealer supply and fit, partly due to my concerns over gearbox overheating, but also no indie would guarantee the electrical installation wouldn't mess with the car, granted the W221 is more complex, but...

The MB electrics is 13 pin, with a 13to7 adapter. Has your caravan got ATS (a stabiliser) as well as 13 pin electrics? Also is the hitch an AlKo hitch, in which case ensure you have an AlKo towball that gives you vertical clearance for the stabiliser. Sorry if its granny sucking eggs.
 
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EmilysDad

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.., but...

The MB electrics is 13 pin, with a 13to7 adapter. Has your caravan got ATS (a stabiliser) as well as 13 pin electrics? Also is the hitch an AlKo hitch, in which case ensure you have an AlKo towball that gives you vertical clearance for the stabiliser. Sorry if its granny sucking eggs.

Also bare in mind that often OE 13 pin aren't wired up to supply caravan fridges & battery charging ie only ie road lighting only
 

Naraic

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I've recently put a towbar on my W221, if I may, I'll give you my rationale:

The main issue is around transmission cooling. Can you afford a new gearbox if you go aftermarket and you overheat the box? Earlier S212 cars required the cooling fan upgrade, as do the BluTec models.

The second issue is the interface with the electronics on your car. The MB kit is plug and play and will give you everything required. Aftermarket may not, despite what the supplier says.

Does your car have the self levelling rear suspension?

There is an OEM towbar available from MB, that is the full monty. Your indie would be able to get this for you at 'trade' plus fitting I would have thought.

I ended up main dealer supply and fit, partly due to my concerns over gearbox overheating, but also no indie would guarantee the electrical installation wouldn't mess with the car, granted the W221 is more complex, but...

The MB electrics is 13 pin, with a 13to7 adapter. Has your caravan got ATS (a stabiliser) as well as 13 pin electrics? Also is the hitch an AlKo hitch, in which case ensure you have an AlKo towball that gives you vertical clearance for the stabiliser. Sorry if its granny sucking eggs.


The car is self leveling.
 

keefysher

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Also bare in mind that often OE 13 pin aren't wired up to supply caravan fridges & battery charging ie only ie road lighting only

The current (see wot I did there? :D ) MB OE 13 pins are wired for 12 of the 13 pins to provide fridge and battery charging. MB are getting better at this.

JLR build all their vehicles except Evoque with harnesses and tow ball sockets straight off the line. The Disco replacement fixed tow balls are not AlKo fitment, leading to caravans unhitching on sudden vertical alignment shifts. Toyota Land Cruiser swan necks are also too short. I had a hired Disco gratis from MB and found these things out, nightmare time trying to get away for first trip with new caravan :(:(

Always good to ask a fitter of towbar wiring how many pins are powered, if they say 13 they lie :mad:
 

keefysher

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The car is self leveling.

Thanks Ciaran, wasn't certain the 220 was. More reason to get an OE towbar imo. The car should be coded so it recognises the load being applied when 1 the caravan is hitched and 2 when the electrics are plugged in.

The ATS will self check as soon as the 13 pin plug is connected and the LED should go green if all ok.

This caravan towing lark has come on a bit :D:D
 
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Coopergreg

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Thanks for all the replies.

Suspension is definitely self-levelling.

I think there is an existing transmission oil cooler as the only suggested upgrade is the fan. I've googled but haven't been able to find any photos/drawings/schematics to show where it is.

I'm getting dedicated electrics and a the necessary coding from a reputable recommended local towbar company (United Towbars).
 

keefysher

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What caravan do you have?
 

hotrodder

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The transmission [strike]cooler[/strike] heat exchanger is usually built into the rad as it typically keeps the atf within a narrower temp range than a seperate air-oil cooler i.e. prevents over cooling without needing additional thermostats for a seperate atf air-oil cooler and helps get the atf upto temp more quickly

Pic of a rad here http://www.kuehler-rath.com/Mercedes-Motorkuehler-22223-20-, the two silver coloured hex fittings on the rhs are the atf inlet/outlet. Just a simple loop through a finned tube inside the rad tank
 
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Coopergreg

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I'm getting a Witter detachable bar which has an Al-Ko towball as standard, with dedicated electrics and coding.

If I do need the 600W fan in the end, MD Motorcare can fit cheaply, and I can get a non-OEM one online for around £200 (vs Mercs £338).

Van will be a Sprite Major 6TD with stabiliser, so under 85% kerbweight.
 
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Coopergreg

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It's a general guide, not just the CC's, and it's sensible to not tow something too close (or above - max for mine is 2100kg!) to the car's weight.
 

keefysher

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For the cost of the fan, I'd fit it tbh. All bases covered.

Nice looking 'van, enjoy it. Should be in time for getting away at Easter.

The 85% is a good guide, if nothing else it stops you filling the 'van with clutter that never sees the light of day.

We had a MH that was full to the gunnels. With the caravan we have 1 suitcase for clothes for 3 people. Focusses the girls on what is actually needed :p:p
 

EmilysDad

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It's a general guide, not just the CC's, and it's sensible to not tow something too close (or above - max for mine is 2100kg!) to the car's weight.

I was just saying ...... some seem to believe 85% a legal requirement
 

EmilysDad

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....

The 85% is a good guide, if nothing else it stops you filling the 'van with clutter that never sees the light of day.

....

Would you please tell EmilysMum :( ....... we seem to carry loads of stuff that never ever sees light of day and clothes for every single weather condition in the world. :cool:
 
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Coopergreg

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Anyone know if there is a 'transmission oil temperature high' warning at all? I can't see anything in the user manual, so assume you'd only see it as a rise in the coolant temperature on the dial on the dashboard?

Thanks
 

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