Towing with an ML250

keefysher

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Thule do do some really nice kit. Very technically advanced, although as with everything you pay for what you get...

Indeed they still do. Been using Thule for decades.Have a pair of gutter fix roof bars from my first car, a Viva HB that saw some miles with a Kayak on the roof!!!

My point, that went 747, was that you don't have to pay. The VeloCompact RRP is £445. https://www.thule.com/en-gb/gb/bike-rack/towbar-bike-racks/thule-velocompact-927-_-927 However with some googling and use of voucher codes, you can get it for £300 over 12 months interest free :):) So you gain in a couple of ways. Lower overall outlay, not in one payment, maintain a credit reference if you have no other borrowing.

Realised that second hand Thule sells well. Whilst clearing out the shed found a set of Thule Roof Bars for an X-Trail, sold for £70. They were on a 55 plate car and were part of the lease not handed back as the Lease Co didn't want accessories back.

A Back Up Box and Easybase went for £50 more than paid for 10 years ago, despite knocks and scrapes.

W211 Roof Bars went for £10 more than paid for in 2005.

Anyone want a set of roof bars for a MkII Astra GTE? Still in my shed.

So, we guys don't just hoard crap as the Mrs reckons, we collect and sell antiques at a future point to realise cash :shock::shock: Unlike those wardrobes full of dresses that never see the light of day :shock::shock:
 
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John Love

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Many thanks for your very comprehensive response Craig. Perhaps my "considerable extra strain" comment was an exaggeration but I wonder if regular towing would shorten service intervals.

Anyway, as keefysher says, it makes the factory fit option somewhat of a bargain. Out of interest, does the EPC for the 350 show the higher rated blower?
 

Craiglxviii

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Many thanks for your very comprehensive response Craig. Perhaps my "considerable extra strain" comment was an exaggeration but I wonder if regular towing would shorten service intervals.

Anyway, as keefysher says, it makes the factory fit option somewhat of a bargain. Out of interest, does the EPC for the 350 show the higher rated blower?

You're very welcome, and it was mainly a copy & paste job in any case ;) Yes, the trailer hitch retro parts for the 350 are identical to the 250 including the 850W blower unit.
 

turbopete

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seems a lot of work to have all the stuff added (and a lot of expense) when IMO it COULD (and SHOULD) be done ANYHOW at the design stage.ive seen few, if ANY manual vehicles with an oil cooler for the gearbox, and never heard of one being killed PURELY because it was used to tow (and look how many transits etc run WAY overloaded, with huge trailers etc and never an issue) and probably explains why, where I grew up, the farmers in the area STILL wont entertain an auto transmission (its also one of many reasons I wouldn't have one out of choice) so it does make me wonder, despite all the auto transmission 'fanboys' on here, is there a fundamental problem with autos? id say that there was. either insufficiently cooled as standard, or theyre NOT, despite what the 'fanboys' here say, any use for towing AT ALL!!!!

but as usual, I'm sure I will get shot down for daring to mention such a thing as autos being less than ideal for something, but if I buy a car that's capable of towing 2-3 tonnes, I don't expect to have to carry out ANY modifications other than those required to physically attach whatever I'm towing, to the vehicle I'm towing with, and provide the necessary electrical supplies to whatever I'm towing.
 

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but as usual, I'm sure I will get shot down for daring to mention such a thing as autos being less than ideal for something, but if I buy a car that's capable of towing 2-3 tonnes

Bad Pete!!!!!!
 
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John Love

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You're very welcome, and it was mainly a copy & paste job in any case ;) Yes, the trailer hitch retro parts for the 350 are identical to the 250 including the 850W blower unit.
That may well surprise a few people.......
 

Craiglxviii

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Bad Pete!!!!!!
It surprised me. We don't fit additional tranny coolers to any autoboxes. However it does fit with German design philosophy- why use one ton of large (simple) parts to do a job when you can use five tons of (complex) ones instead?

That's highly simplistic btw, behind that is a requirement to use a design that precisely meets its criteria without needing to be significantly over engineered. (No, German product tends not to be over engineered, just consistently very well engineered).

Pete, the answer is, as always, COST.

Oh and on the auto vs manual thing, in this case it's understandable- autoboxes use oil as a working fluid, putting that under additional thermal stress requires greater heat transfer capacity; if that isn't built in it needs to be added.
 

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Really interesting comment from someone who started caravanning in the 70's with a Renault 5 towing a Sprite 400. On strong headwind days I was stuck in 3rd gear, it wouldn't pull in 4th.
 

keefysher

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Really interesting comment from someone who started caravanning in the 70's with a Renault 5 towing a Sprite 400. On strong headwind days I was stuck in 3rd gear, it wouldn't pull in 4th.

The 9 speed autobox on my GLE350 won't get into 9th at the legal speed for towing a caravan in the UK, either ;)

As the gearboxes, like the cooling systems, tyres etc are all aimed at emissions for the relevant tests, the real world operation is somewhat different.
 

turbopete

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It surprised me. We don't fit additional tranny coolers to any autoboxes. However it does fit with German design philosophy- why use one ton of large (simple) parts to do a job when you can use five tons of (complex) ones instead?

That's highly simplistic btw, behind that is a requirement to use a design that precisely meets its criteria without needing to be significantly over engineered. (No, German product tends not to be over engineered, just consistently very well engineered).

Pete, the answer is, as always, COST.

Oh and on the auto vs manual thing, in this case it's understandable- autoboxes use oil as a working fluid, putting that under additional thermal stress requires greater heat transfer capacity; if that isn't built in it needs to be added.

again missing the point though. the fan cools EVERYTHING so if the manual gearbox version of the car has fan 'x' and its man enough for the job, it should be throughout the range. as for the cost, well we keep being told that the more of something you buy (from a company point of view especially) the cheaper it gets, so why not just fit it properly in the first place? and whilst I cant say for certain who it is you work with/for, you have said you (presumably as a manufacturer/oem) don't fit extra coolers, which surely PROVES my point. either MB boxes are substandard, the cooling is substandard, or BOTH. ive never known them be fitted to any Fords (certainly not where I worked) nor did I see any fitted in my short spell in a Nissan/Renault dealership. so, if what are, allegedly, inferior cars, can do without, why cant MB?
 

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again missing the point though. the fan cools EVERYTHING so if the manual gearbox version of the car has fan 'x' and its man enough for the job, it should be throughout the range. as for the cost, well we keep being told that the more of something you buy (from a company point of view especially) the cheaper it gets, so why not just fit it properly in the first place? and whilst I cant say for certain who it is you work with/for, you have said you (presumably as a manufacturer/oem) don't fit extra coolers, which surely PROVES my point. either MB boxes are substandard, the cooling is substandard, or BOTH. ive never known them be fitted to any Fords (certainly not where I worked) nor did I see any fitted in my short spell in a Nissan/Renault dealership. so, if what are, allegedly, inferior cars, can do without, why cant MB?

Good point Pete. Jap 4WD's like Patrols and Land Cruisers are designed to tow in hot conditions and don't need extra cooling. They do have proper coolers, not silly little heat exchangers like MB. I did have to add a cooler to a Nissan Pathfinder - 3 litre petrol auto - to keep auto cool enough in our conditions, so Japs do miss the boat sometimes. This is really one area where manufacturers SHOULD over-engineer to cope with unusual conditions.
As an aside re manuals, I towed with manual for years. I do find auto much easier when putting a van on site in awkward positions. Riding a clutch was never nice and not as easily controlled as auto. It is common to see manual trannys give trouble when used in overdrive for towing. Many don't realise that it is NOT recommended when towing a fairly heavy load. I always towed in direct drive 4th in my Nissan Patrol in the old days. No difference to economy and less gear changes on hills.

Ian.
 

Craiglxviii

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again missing the point though. the fan cools EVERYTHING so if the manual gearbox version of the car has fan 'x' and its man enough for the job, it should be throughout the range. as for the cost, well we keep being told that the more of something you buy (from a company point of view especially) the cheaper it gets, so why not just fit it properly in the first place? and whilst I cant say for certain who it is you work with/for, you have said you (presumably as a manufacturer/oem) don't fit extra coolers, which surely PROVES my point. either MB boxes are substandard, the cooling is substandard, or BOTH. ive never known them be fitted to any Fords (certainly not where I worked) nor did I see any fitted in my short spell in a Nissan/Renault dealership. so, if what are, allegedly, inferior cars, can do without, why cant MB?

No I'm not missing the point, Pete, although I think you missed the point I made. To take your post in order:

the fan cools EVERYTHING so if the manual gearbox version of the car has fan 'x' and its man enough for the job, it should be throughout the range.

That assumes that the heat output from a manual transmission is the same as an autobox; it isn't by quite a way.

as for the cost, well we keep being told that the more of something you buy (from a company point of view especially) the cheaper it gets

Again that's not strictly true either. There IS such a thing as economies of scale or volume effect, but it isn't a linear relationship, more a series of steps with each of those steps representing the output of a tool, a plant or multiples thereof. For instance, if one tool can produce 100,000 parts per year and the volume demand increases to 110,000, the second tool will only be 10% utilized and therefore the costs for the second tool's parts output will be significantly greater than those of the first.

so why not just fit it properly in the first place?

Because fitting it, costs money. Ah hah, I hear you cry, why not increase the cooling capacity of the rad in the first place to take this into account? Because that also costs money.

Here we get into a very sticky, amorphous area of design and specification called "rightsizing", which basically means that the OEM will incorporate the right amount of kit at the right performance for that particular model and grade in a particular market (this is why cars sold in the Middle East usually don't come with seat heaters as standard fit, for example). Now, every OEM has a different rightsizing philosophy and that is linked to their sales philosophy. Ze Germans will sell you a car with maybe 3-4 grades available; if you want a radio, tick the radio option (no joke, BMW were like that until not so long ago), and the same with anything else optional. The Japanese and Americans will sell you a car with maybe 6-7 grades, and a correspondingly smaller amount of payable options. The key point is that a German base spec car with no options may be considerably cheaper than one sold with another sales philosophy, which includes a whole load of "standard" kit but far fewer options. The catch is, of course, that the German philosophy allows for a much finer tuning of the individual vehicle whilst at the same time offering a considerable amount of upselling at the dealership. Would sir like the heated wash nozzles with that? £250 please. On a Kia (just making this example up btw) selecting that same option might cost you £2,500 to get the next spec grade of car up where heated wash nozzles are standard fit, as they're not offered as a payable option. And so on.

So, what we see here is that at least for the ML/ GLE- and presumably E-klasse as a range- is that the cooling system is geared for no towing or very light towing; if towing is required then it is specified on purchase (and paid for). if it's not then it isn't. This also has the benefit of pushing more people to buy new cars than used. It's neither right or wrong, it's just a manifestation of a different sales philosophy.

and whilst I cant say for certain who it is you work with/for

Oh good ;)

you have said you (presumably as a manufacturer/oem) don't fit extra coolers, which surely PROVES my point

No, it demonstrates that we have a very different sales, manufacturing, parts control and design philosophy than MB.

Actually, this brings me to another point. Design standards and tests. I've mentioned these before. Now, it could be that MB's towing tests are for (made up example) 120% of vehicle mass at 120km/h for 8 hours, whilst another manufacturer's tests are for 90% of vehicle mass at 100km/h for 2 hours. So, MB's extra cooling kit is required to meet their test requirements; another manufacturer's equivalent car might not pass MB's tests without that additional kit. I've seen similar issues before with MB test standards, although not for towing setups, so this wouldn't surprise me. It goes both ways of course.

either MB boxes are substandard, the cooling is substandard, or BOTH.

Or the cooling meets the company's test standards for the car as it is sold (which is absolutely the case), only MB do not build in extra capacity to meet their towing test standard unless it is specified at the point of order (which looks to be the case).

ive never known them be fitted to any Fords (certainly not where I worked) nor did I see any fitted in my short spell in a Nissan/Renault dealership. so, if what are, allegedly, inferior cars, can do without, why cant MB?
Nissan, Renault and Ford all tend towards the "larger number of standard grades with more giveaway within those grades", so that doesn't surprise me. They all also have very widely different test standards to all eachother and all to MB as well. Some much lower, some much greater, dependent on what the part or system being tested is/ does.
 

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I would think that 99% of cars with after market tow bars still have the original/standard cooling fan(s) ;)

I've no doubt that they do, and that those are perfectly adequate to cover almost all their towing performance too...
 

LostKiwi

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There is a very good reason why manual gearboxes don't have cooling fans/radiators/heat exchangers.
With a very few notable exceptions they don't have an oil pump so lack the means to circulate the oil through a cooler.
The only manual boxes I know of with internal pumps are Land Rover ones (forced lubrication to the mainshaft).

Autos also stress the oil far more than a manual - the oil is used as a transmission medium to transfer the torque/power to the driven wheels, as an hydraulic fluid to control clutch packs and bands and as a lubricant. Oil in a manual is only used for lubrication.

I remember as a teenager/early 20s we fitted auxiliary transmission coolers to vehicles used for a lot of towing.

So the question of is the MB cooling or autobox substandard.... I would say no as the vehicle is designed not to tow so the cooling and autobox are specced accordingly. If someone desires to tow then the factory kit includes upgraded cooling capacity since the design parameters for the vehicle as used by 90% of people have changed. If the vehicle came with a towbar as standard and then required an additional cooling kit before you could use it then yes that would be poor.
 

turbopete

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No I'm not missing the point, Pete, although I think you missed the point I made. To take your post in order:



That assumes that the heat output from a manual transmission is the same as an autobox; it isn't by quite a way.



Again that's not strictly true either. There IS such a thing as economies of scale or volume effect, but it isn't a linear relationship, more a series of steps with each of those steps representing the output of a tool, a plant or multiples thereof. For instance, if one tool can produce 100,000 parts per year and the volume demand increases to 110,000, the second tool will only be 10% utilized and therefore the costs for the second tool's parts output will be significantly greater than those of the first.



Because fitting it, costs money. Ah hah, I hear you cry, why not increase the cooling capacity of the rad in the first place to take this into account? Because that also costs money.

Here we get into a very sticky, amorphous area of design and specification called "rightsizing", which basically means that the OEM will incorporate the right amount of kit at the right performance for that particular model and grade in a particular market (this is why cars sold in the Middle East usually don't come with seat heaters as standard fit, for example). Now, every OEM has a different rightsizing philosophy and that is linked to their sales philosophy. Ze Germans will sell you a car with maybe 3-4 grades available; if you want a radio, tick the radio option (no joke, BMW were like that until not so long ago), and the same with anything else optional. The Japanese and Americans will sell you a car with maybe 6-7 grades, and a correspondingly smaller amount of payable options. The key point is that a German base spec car with no options may be considerably cheaper than one sold with another sales philosophy, which includes a whole load of "standard" kit but far fewer options. The catch is, of course, that the German philosophy allows for a much finer tuning of the individual vehicle whilst at the same time offering a considerable amount of upselling at the dealership. Would sir like the heated wash nozzles with that? £250 please. On a Kia (just making this example up btw) selecting that same option might cost you £2,500 to get the next spec grade of car up where heated wash nozzles are standard fit, as they're not offered as a payable option. And so on.

So, what we see here is that at least for the ML/ GLE- and presumably E-klasse as a range- is that the cooling system is geared for no towing or very light towing; if towing is required then it is specified on purchase (and paid for). if it's not then it isn't. This also has the benefit of pushing more people to buy new cars than used. It's neither right or wrong, it's just a manifestation of a different sales philosophy.



Oh good ;)



No, it demonstrates that we have a very different sales, manufacturing, parts control and design philosophy than MB.

Actually, this brings me to another point. Design standards and tests. I've mentioned these before. Now, it could be that MB's towing tests are for (made up example) 120% of vehicle mass at 120km/h for 8 hours, whilst another manufacturer's tests are for 90% of vehicle mass at 100km/h for 2 hours. So, MB's extra cooling kit is required to meet their test requirements; another manufacturer's equivalent car might not pass MB's tests without that additional kit. I've seen similar issues before with MB test standards, although not for towing setups, so this wouldn't surprise me. It goes both ways of course.



Or the cooling meets the company's test standards for the car as it is sold (which is absolutely the case), only MB do not build in extra capacity to meet their towing test standard unless it is specified at the point of order (which looks to be the case).


Nissan, Renault and Ford all tend towards the "larger number of standard grades with more giveaway within those grades", so that doesn't surprise me. They all also have very widely different test standards to all eachother and all to MB as well. Some much lower, some much greater, dependent on what the part or system being tested is/ does.

and as has been pointed out earlier, few, if any Japanese cars need extra coolers, even in Australias climates (much hotter than ours) so if the fans aren't up to the job here, and the uprated ones are, are we saying its a different cooler/fan again for a different market? and if so, surely developing different parts for different markets costs far more than doing it right in the first place? after all, isn't that why places like the UK, Japan and Australia are so expensive compared to the likes of the USA for cars? because they have to convert so much to make the cars RHD after being designed for LHD? or is that just the bull$h!t line we get fed for being ripped off? and seriously, who actually designs a 4x4 and DOESNT expect it to be used, at some point, for towing?
 

Srdl

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and seriously, who actually designs a 4x4 and DOESNT expect it to be used, at some point, for towing?
Many 4x4s seemed to be just used on the school run these days so perhaps they are designed with that customer in mind?
 

Craiglxviii

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Many 4x4s seemed to be just used on the school run these days so perhaps they are designed with that customer in mind?

They're SUVs. Not off road towing cars. They're designed for a specific customer profile- 43, architect, 2.4 children, married (yes, really that specific).
 

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