Towing with an ML250

John Love · Sep 11, 2017

Following on from my intro thread:

We have very recently decided that a W166 ML is the car for us and because the car will be a daily driver the lower running costs of the ML250 would be appreciated, especially as during a test drive I didn't miss the performance of my current X5 as much as I had expected to. The possible fly in the ointment is that we occasionally tow a caravan so will need a towbar. Information is somewhat difficult to find and the Mercedes ML options list confusingly states that a towbar can only fitted in conjunction with the larger fuel tank on the ML350. Also, you have to discuss your towing requirements with the retailer. I have read elsewhere that the ML250 needs a bigger fan for extra cooling plus the fuel tank has to be moved(???) so I'm wondering what Mercedes actually do to each model when the towbar option is selected?

Somewhat confused and concerned, I have decided to rule out a retro fit and have managed to locate an ML250 AMG Sport with a factory fitted towbar which we are driving on Wednesday.

Given how happy we are with everything else, are there any potential problems towing 1600kg with the 250? I know it is well within the recommended 85% of the kerb weight but I'm obviously wary of straining the engine and gearbox. Is the cooling fan issue only on the 250 and therefore a 350 would be ok for a retro fit? What is the handling like when towing? My X5 has got self levelling suspension which makes a big difference in keeping the caravan under control in bends and when braking, the car we are looking at does not have Airmatic or Active Curve options.

Apologies for the long post and many questions but if I'm spending £28k+ I want to make sure I'm not buying trouble so any advice or relevant information would be greatly appreciated.

BTW Flamers about caravans will be politely ignored

Cheers, John

turbopete · Sep 11, 2017

book a proper holiday, it'll be cheaper in the long run

seriously though, I don't imagine they do all that much to the cars themselves as it would make the towing packs horrendously expensive. I would have thought a larger fuel tank would only serve to compensate for the reduced fuel range when towing, if its needed at all. as for extra fans etc, to be honest, I thought those days were long gone, but obviously Mercedes must feel that their auto boxes are more fragile than everyone on here seems to be willing to admit, if they overheat that easily.

that said, it should tow 1600kgs easily, especially given the actual bulk of the car. I was reading online (on a caravan forum, as it happens) that even my humble 2.0 diesel Mondeo will pull that for FUN (according to caravanners)

as for how they handle when they tow, I cant comment on that, as ive never driven a W166 BUT if I'm honest, I think the standard set up on the X5 was less than optimal for towing. anything ive ever had on the back of the Mondeo (which has standard springs etc) or any other car ive towed with (from Series 2a land rovers onwards) has never been an issue.

John Love · Sep 11, 2017

I've never owned a standard X5 and as I stated, mine has got self levelling suspension so it tows brilliantly. To be honest I'm finding the lack of official information regarding factory fit towbars very frustrating. It has to be said that the lack of knowledge from the Mercedes main dealers I've asked is a tad disappointing too. Maybe I'm looking in the wrong place or asking the wrong dealers, hence my post on here.

Given that I only go away in the caravan 4 or 5 times a year and I certainly don't tour with it so it's actually only hitched up 8 or 10 times, am I worrying unduly?

mikestrivens · Sep 11, 2017

Maybe you should go with a manufacturer that can answer your questions. Mercedes dealers often border on the incompetent if you read many of the posts here.

turbopete · Sep 11, 2017

id say you are worrying excessively yes. its probably got a towing capacity of around 2 tonnes so 1600kgs should be nothing to it.

I cant remember which site I was on earlier (I stumbled onto it by accident) but Mondeos are towing that weight with ease, so surely a 4x4 should be able to!

M80 · Sep 11, 2017

Mercedes-Benz M Class ML250 CDi BlueTEC SE 5dr Auto | Top Gear

Your anticipated purchase may vary a little from this one, but a towing max of near 3 tonnes is specced here and that is as I would expect.

Like you though I would investigate any need for greater gearbox cooling but the AMG with a factory fitted set up would already have all that's needed surely, especially in this country.
I would prefer the 350 for the better engine though.

EmilysDad · Sep 11, 2017

Similar car .... but my R320 tows my Coachman with ease (despite its alleged turbo problems) and it tips the scales at1650kg with a max weight of 1800kg (ish) The tow bar was on it when I bought the car, but doubt that any cooling or fuel tanks were upgraded.

John Love · Sep 11, 2017

Thanks for your responses guys. I'm fairly sure that the factory fit would mean that everything required would have been done so I'm worrying unduly. However, I still think it's poor that I cannot find out exactly what is done when a towbar is specced from new.

As for the 4 pot vs 6 pot question.....my heart wants a 350 but my head and wallet say that a 250 makes more sense. I had fun for the first 3 years in the X5 Sport and really enjoyed the performance but I'm considerably lighter footed now, mainly for the gains in economy, so I won't miss the performance.

I suspect that towing with a 250 won't be quite as economical because I'll be working the engine harder but as towing represents less than 5% of my driving it's not a huge issue.

Craiglxviii · Sep 11, 2017

I doubt very much indeed that you'll have any problems towing a 1600kg Coachman with an ML250. You'll also notice not much of a difference in running costs with a 350; the bigger engine is offset by lower revs required through the power range (the 2.2 litre is quite a revvy engine to get the power).

M80 · Sep 11, 2017

I fully appreciate your motives re the 250, and with the 2 turbos it's very impressive and even smooth.
I, like you, drive for economy and don't need sports car performance. I generally set the cruise at 58mph when possible. But only one reason for my recent upgrade to the 3 litre V6 is that the smoother and quieter drive is worth the small sacrifice in economy. Especially when you consider your increased per mile cost will be negligible compared to the other costs, depreciation likely the highest.
I can only imagine the extra torque, and better if mapped, would be far nicer when towing.

Imho.

John Love · Sep 11, 2017

There's no doubt that MLs with factory fitted towbars are like the proverbial rocking horse poo. It also appears that only the 250 has to have anything extra done by the factory when a towbar is ordered though I've not been able to get that confirmed.

With that in mind I'm wondering if the best thing I could do is find a 350 that meets all my other requirements then get a towbar retro fitted. The money I saved on the purchase price would more than cover the extra tax, servicing and fuel costs.....plus it would be a 350!!!!!

Craiglxviii · Sep 11, 2017

Tow bar fitting = £480 for a removable one...

Srdl · Sep 11, 2017

John Love said:
.....plus it would be a 350!!!!!

He's weakening!

oigle · Sep 12, 2017

Probably is not as important in your climate but I found my W163 with 270cdi motor experienced auto oil overheating when towing my 1600kg van here in Oz. The oil blackened quickly and smelled burnt. After any long hill climbs, the auto would not change into higher gears for quite a while after cresting the hill - an obvious attempt to increase the auto oil circulation through the heat exchanger to get the temp back to normal. I changed the oil quite often which was an expensive procedure. Cheaper then gearbox repairs tho'.
I eventually bit the bullet and inserted an extra front mounted cooling rad into the system through which the auto fluid was sent prior to going through the OE heat exchanger that is supposed to keep the fluid at a suitable temp. Completely cured the problem and oil now stays clear and gear changes never vary. Well worth the trouble. Not a huge expense.

Ian.

John Love · Sep 12, 2017

From what I've been able to deduce, when a 250 has a factory fitted towbar the extra cooling work required is done. It appears the same work is not required on a 350 so fitting an after market towbar is far more straightforward.

That may well be a simplification so I'm hoping a Merc mechanic will give me a definitive answer.

keefysher · Sep 12, 2017

A few words of wisdom through experience of retro fitting an OEM towbar to a W221 S350L 2013 MY.

The cooling system as built in the factory will meet the requirements for that exact vehicle. So don't assume it has a bigger fan and coolant pump just because it has a bigger engine. The different NOX controls will determine the cooling system bits. BluTec vs Blue Efficiency may give a clue. TheAMG Line is the shiny trim bits and brakes, not necessarily any 'performance' mods.

Your dealer will be able to determine the exact build from the Vin number.

My S350 required the cooling system mods. The cost of the OEM retrofit towbar, electrics and cooling system should have been £3200. I didn't pay that due to delays in supply and got the parts gratis. My thinking was £800 for cooling mods vs new gearbox at £12k if warranty was voided as I knowingly, had I not had the cooling mods, didn't get the cooling bits changed.

Look a bit harder and see if a GLE is affordable, with a factory fitted towbar, the electric deployable one, like this wot I have on mine for £950 as built in the factory:

The Air Matic on both MB tow cars makes things very comfortable. GLE driver aids like Distance Pilot brings a whole different driving experience with the caravan hitched, as do Active Lane Assist and the funky camera system that aligns the lowball to the hitch. Once you decide to unhitch, wind the jockey wheel to release the hitch, push the button to retract the tow bar and watch people wonder how you towed the caravan!!

In respect of towing capability. A caravan is not like a trailer. The 3500Kg or wotever weight limit is based on a trailer with a very low centre of gravity and not very tall or slab sided and subject to the same effects a large tall, long, wide box with a higher CoG which is why there is the recommended 85% guidance. i.e. the caravan should be no more than 85% of the kerb weight of the tow car. It's also the ability of the drive train to do a hill start on a 12% gradient.

I tow a Sterling Continental single axle caravan, that is around 1900Kg loaded, at 7.49m (24'6") long, 2.26m (7'5") wide and 2.61m (8'7") tall. A whole different towing experience to a trailer with a metre of concrete in it!!

John Love · Sep 12, 2017

Hi keefysher, many thanks for your post, it is exactly what I need to know regarding factory vs retro fit towbars.

I completely agree with what you say about towing a trailer vs a caravan, they are very different things. I pull a Coachman Pastiche with a max weight of around 1500kg which is obviously well under the recommended caravan towing guidelines of 85% of the unladen weight of the car. Even so, there is still considerable extra strain on the engine and gearbox so to try to ensure there are no future problems it's factory fit or nothing.

As mentioned, the 250 we are test driving has a factory fit and in all the looking I've done I've only seen one 350 for sale that had one but it was older than we want with too many miles. Unfortunately our budget simply won't stretch to a GLE.

Craiglxviii · Sep 12, 2017

John Love said:
Hi keefysher, many thanks for your post, it is exactly what I need to know regarding factory vs retro fit towbars.

I completely agree with what you say about towing a trailer vs a caravan, they are very different things. I pull a Coachman Pastiche with a max weight of around 1500kg which is obviously well under the recommended caravan towing guidelines of 85% of the unladen weight of the car. Even so, there is still considerable extra strain on the engine and gearbox so to try to ensure there are no future problems it's factory fit or nothing.

As mentioned, the 250 we are test driving has a factory fit and in all the looking I've done I've only seen one 350 for sale that had one but it was older than we want with too many miles. Unfortunately our budget simply won't stretch to a GLE.

keefysher · Sep 12, 2017

Which makes a factory fit on first order a bargain!!

Modern bike carriers are funky too when on the lowball, especially with a tall car like a ML/GLE for putting bikes on the roof. Although when towing the caravan I use the step to put the bikes on the roof of the car.

Got a Thule VeloCompact 973 recently. On an interest free deal, £25/month for 12 months. Very clever bit of kit.

Craiglxviii · Sep 12, 2017

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

Towing with an ML250

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