Towing a caravan . Cooling issues ?

[GrahamT]

I have just had fitted a tow bar with dedicated electrics to my used W213 estate diesel. The MB dealers suggested that the cost for them to do it would frighten me. (it did !) so I went to a tow bar specialist on their suggestion .
I did question my local dealers and was told that the factory fitted upgrades are to permit towing the Maximum weight up an Alp in 40c temperatures. I have no plans to do that !

On a caravanning club forum I recommendet the company I used and then got dire warnings about my failure to have the 'proper MB cooling upgrades for the engine and gearbox'.

My question is about other's experiences about going down the road I have. Is there any record of problems resulting from towing well under the 2200 KG limit which MB list for this model ? (My caravan has a mtpw of 1300 kg.

 

[JHS]

I have just had fitted a tow bar with dedicated electrics to my used W213 estate diesel. The MB dealers suggested that the cost for them to do it would frighten me. (it did !) so I went to a tow bar specialist on their suggestion .
I did question my local dealers and was told that the factory fitted upgrades are to permit towing the Maximum weight up an Alp in 40c temperatures. I have no plans to do that !

On a caravanning club forum I recommendet the company I used and then got dire warnings about my failure to have the 'proper MB cooling upgrades for the engine and gearbox'.

My question is about other's experiences about going down the road I have. Is there any record of problems resulting from towing well under the 2200 KG limit which MB list for this model ? (My caravan has a mtpw of 1300 kg.

We tow an Eriba Triton MGW1200kg with an S205 with no issues. There are some extremely anal people on the caravan forums!!

 

[jasonh]

I doubt you will have a problem. As stated the modifications MB makes are to ensure the car has adequate cooling under worst case conditions.

However if your car is under MB warranty be careful - they are likely to reject any claim for anything that could even slightly be related to towing something too heavy without an approved MB towbar installation.

I can't say exactly what the official MB installation would have included but I was recently looking at petrol BMW's. When they have a towbar fitted they "have" to have the cooling upgrade which is simply to fit the same cooling fan that the diesel models have....however the cost is huge because the wiring loom can't support the extra load and has to be replaced as well.

 

[Bobby Dazzler]

It will probably be OK, for most of the time at least. The additional cooling is to deal with that scenario which doesn’t often happen but if you tow often enough, far enough, then it might. If you have decided that risk is worth taking then just keep a close eye on temperatures in high risk situations and act accordingly.

Previously car manufacturers would engineer and build every car to deal with any situation, but in the current climate unnecessary cost and weight (which won’t be used by the majority of drivers) is best avoided, and reserved for those who really need it, which makes retrofitting properly more costly.

 

[ALFAitalia]

I'm sales manager at a main caravan dealer....have been 20 years. Not seen a car that needed extra cooling to tow since the 80s!......even then it was just coolers for auto transmission's.......the stock cooling fan can keep up with the engine no problem at all.

 

[Benzowner]

I had a W210 E300 diesel estate with MB tow bar fitted and from memory the additional cooling was for gear box only and consisted on a 12mm ish dia pipe which ran from the gearbox up the sire of the radiator bent 360 degrees and returned to the gearbox, it may have been stainless steel, probably why so expensive The last car I towed with was a W245 B180 towing a 1325kg van and we had no additional cooling on that.

The thing is, if the manufacturer says it will tow X Kg, I have yet to see that maximum tow weight subject to additional fixtures and fittings.

 

[audiavant]

Does the suggested max towing weight have an inbuilt safety factor?(ie a percentage over the max weight advised?)

 

[Martyn_n]

I was looking at nearly new Skoda Kodiaqs as a tow car. Unless the original owner specified a towbar OR tow bar preparation when the car was new they now come with zero plated towing weight so it would be illegal to fit a towbar. Clearly Skoda think the tow bar prep is very important (whatever is involved in it). Obviously the number of nearly new Kodiaqs where the option had been ticked were few and far between.

Even on the website the following was in very small print;
"Please note: If a tow bar or tow bar preparation is not fitted on the car, the VIN plate may not show any towing weights and the car will never be eligible for towing. As such it may not be possible to retrospectively fit a tow bar if the car is not fitted with tow bar preparation at Factory."

 

[ALFAitalia]

@audiavant You cant tow the maximum allowed towing weight in this country anyway. In the UK you cant tow a caravan (or anything else) that's heavier than the towing car regardless of what's claimed by the maker.....Example....My Jeep has a 3.5 ton tow limit....but "only" weights 2.1 ton....so 2.1 ton is its legal limit in this country. The max tow weight is just telling you what it can tow without breaking......a bit like your cars claimed top speed.....it will go that fast but you are not allowed to do it on the road in the UK! Some (gutless!) cars have a max tow lower than their kerb weight....in which case that's fine to tow that much. Certain organisations, like the caravan club, will advise you not to tow above 85% percent of your cars kerb weight.....good advice but as caravans get heavier and cars get lighter is getting more difficult to do and it and has no substance in law anyway. If you do tow something too heavy you risk the wrath of the VOSA inspector (ask me how I know!!)....a group of blokes with a surgically removed sense of humour if ever there were any. But I was towing a customers van, with their plate (not mine) on the back, that was little too heavy and with no mirrors....so I was asking for it. Took all my salesman's patter to talk my way out of that one....but I did!!!!

 

[Petrol Pete]

I'm sales manager at a main caravan dealer....have been 20 years. Not seen a car that needed extra cooling to tow since the 80s!......even then it was just coolers for auto transmission's.......the stock cooling fan can keep up with the engine no problem at all.

Not sure about the exact set up of the OP's car (but it is an automatic) but the cooling pipes on most MB gearboxes run up to a dedicated radiator behind the front grille so its being cooled that way. So logically if MB think the transmission they have fitted needs extra cooling to tow they simply make a plan (bigger/faster fan) to pull more air over said (standard sized) gearbox radiator .

If it were me and I towed a LOT I might just service the transmission more often .

 

[BTB 500]

You cant tow the maximum allowed towing weight in this country anyway. In the UK you cant tow a caravan (or anything else) that's heavier than the towing car regardless of what's claimed by the maker.....Example....My Jeep has a 3.5 ton tow limit....but "only" weights 2.1 ton....so 2.1 ton is its legal limit in this country.

I don't think that's true.

That restriction (and various others) did apply, but only to drivers who had passed their test from 1997 onwards and not taken the separate 'car and trailer' test. However the law changed on December 16th 2021 - the only limitation now is a trailer MAM of 3500 kg (subject to the towing vehicle's plated gross train weight / maximum braked trailer weight / maximum noseweight of course).

Towing with a car

Towing trailers, caravans and horseboxes with a car, including the weight and size limits, and what licence you need to have

www.gov.uk

Of course it's good policy not to tow a caravan that weighs more than the tow car, but I don't believe this is legally enforceable unless it's clearly 'unroadworthy'. And this isn't likely to apply to a low trailer (which doesn't have a caravan's high centre of gravity and side area).

 

[Benzowner]

@audiavant You cant tow the maximum allowed towing weight in this country anyway. In the UK you cant tow a caravan (or anything else) that's heavier than the towing car regardless of what's claimed by the maker.....Example....My Jeep has a 3.5 ton tow limit....but "only" weights 2.1 ton....so 2.1 ton is its legal limit in this country. The max tow weight is just telling you what it can tow without breaking......a bit like your cars claimed top speed.....it will go that fast but you are not allowed to do it on the road in the UK! Some (gutless!) cars have a max tow lower than their kerb weight....in which case that's fine to tow that much. Certain organisations, like the caravan club, will advise you not to tow above 85% percent of your cars kerb weight.....good advice but as caravans get heavier and cars get lighter is getting more difficult to do and it and has no substance in law anyway. If you do tow something too heavy you risk the wrath of the VOSA inspector (ask me how I know!!)....a group of blokes with a surgically removed sense of humour if ever there were any. But I was towing a customers van, with their plate (not mine) on the back, that was little too heavy and with no mirrors....so I was asking for it. Took all my salesman's patter to talk my way out of that one....but I did!!!!

The law changed, you now cannot tow a trailer heavier than the maximum towing limit of the car so your Jeep can tow 3.5tonnes. They keep moving the goalposts

 

[ALFAitalia]

Nope you cant....sorry....but I do this for a living!!!

This is from the page you quoted!

"a trailer over 750kg MAM, as long as it is no more than the unladen weight of the towing vehicle (up to 3,500kg in total)

 

[Qwertycls]

What am I missing here? every farmer in the land (incl me) is towing 3.5t trailers behind 2t pickups

 

[BTB 500]

Nope you cant....sorry....but I do this for a living!!!

This is from the page you quoted!

"a trailer over 750kg MAM, as long as it is no more than the unladen weight of the towing vehicle (up to 3,500kg in total)

Were you replying to me? If so you are quoting from the wrong section:

What you could tow before 16 December 2021​

And as I said, this limitation did not apply to if you passed your test before 1 January 1997 anyway.

Please read the section:

What changed on 16 December 2021​

instead, i.e.

If you passed your car driving test from 1 January 1997, you’re now allowed to tow trailers up to 3,500kg MAM.

Check your car’s handbook to find out its gross train weight (GTW). This is the total allowable weight of the car plus the trailer plus the load.
DVLA will update your driving licence record to show that you’re allowed to tow trailers. You do not need to contact DVLA for this to happen. It will be done automatically. You’ll get category BE added to your driving licence when you next apply to get a new driving licence.

If you passed your car driving test before 1 January 1997, you are not affected by the change.

 

[BTB 500]

Nope you cant....sorry....but I do this for a living!!!

Hopefully this is clear enough (BE is the driving licence entitlement relating to towing with a car)

Category BE​

You can drive a vehicle with a MAM of 3,500kg with a trailer.

The size of the trailer depends on the BE ‘valid from’ date shown on your licence. If the date is:

• before 19 January 2013, you can tow any size trailer within the towing limits of the vehicle
• on or after 19 January 2013, you can tow a trailer with a MAM of up to 3,500kg within the towing limits of the vehicle

Driving licence categories

Driving licence categories - entitlements on your licence and what vehicles you can drive - cars, motorcycles, mopeds, medium and large lorries, minibuses and buses.

www.gov.uk

 

[JHS]

Hopefully this is clear enough (BE is the driving licence entitlement relating to towing with a car)

Driving licence categories

Driving licence categories - entitlements on your licence and what vehicles you can drive - cars, motorcycles, mopeds, medium and large lorries, minibuses and buses.

www.gov.uk

"If you passed your car driving test from 1 January 1997, you’re now allowed to tow trailers up to 3,500kg MAM.

Check your car’s handbook to find out its gross train weight (GTW). This is the total allowable weight of the car plus the trailer plus the load."

I do believe that this is the deciding factor. If your vehicle has a GTW of 2.5 Tonnes there is no way that you can (legally) tow a 3.5 tonne trailer.

My S205 has Gross Vehicle Weight of 2235 and a Gross Train Weight of 4095. Therefore I can (legally) tow a trailer up to 1860 NOT 3500!

 

[BTB 500]

"If you passed your car driving test from 1 January 1997, you’re now allowed to tow trailers up to 3,500kg MAM.

Check your car’s handbook to find out its gross train weight (GTW). This is the total allowable weight of the car plus the trailer plus the load."

I do believe that this is the deciding factor. If your vehicle has a GTW of 2.5 Tonnes there is no way that you can (legally) tow a 3.5 tonne trailer.

My S205 has Gross Vehicle Weight of 2235 and a Gross Train Weight of 4095. Therefore I can (legally) tow a trailer up to 1860 NOT 3500!

There are two completely different things - what a driver can tow based on his/her licence entitlements (that's what changed at the end of last year), and what a vehicle can tow (based on the data plate etc.). Of course for any given combination the lower limit applies, and you're right that it's now very likely to be determined by the vehicle's GTW. I don't know if there are any cars rated to tow over 3.5T but the law does allow for this (as posted above):

The size of the trailer depends on the BE ‘valid from’ date shown on your licence. If the date is:

• before 19 January 2013, you can tow any size trailer within the towing limits of the vehicle
• on or after 19 January 2013, you can tow a trailer with a MAM of up to 3,500kg within the towing limits of the vehicle

Your BE date will be based on when you passed the driving test (or the separate towing test required between 1/1/97 and 16/12/21), but may not yet be shown on your physical licence.

Of course any car will also have a separate (lower) unbraked trailer limit, and a noseweight limit (the lower of the car's rating and the towbar's, if they are different). Specifically for caravans the noseweight guideline for good stability is 5-7% of the laden weight, which can be a limiting factor before the GTW is reached. Using this amount of noseweight is only a recommendation though (like the maximum caravan size of 85%-100% of kerbweight), and you may be OK with a less if the caravan has an effective stability control system (like AL-KO's ATC). I wouldn't personally want to rely on this though as if it fails for any reason you could be left far from home with an unstable outfit.

 

[Bobby Dazzler]

"If you passed your car driving test from 1 January 1997, you’re now allowed to tow trailers up to 3,500kg MAM.

Check your car’s handbook to find out its gross train weight (GTW). This is the total allowable weight of the car plus the trailer plus the load."

I do believe that this is the deciding factor. If your vehicle has a GTW of 2.5 Tonnes there is no way that you can (legally) tow a 3.5 tonne trailer.

My S205 has Gross Vehicle Weight of 2235 and a Gross Train Weight of 4095. Therefore I can (legally) tow a trailer up to 1860 NOT 3500!

Read it literally rather than apply it to your car: it says that YOU are allowed to tow a trailer up to 3500kg, rather than your CAR is allowed to tow up to 3500kg. Driving licenses relate to people, rather than cars.

 

[ALFAitalia]

Even forgetting the legalities of it, towing something that weighs 3.5 ton behind a 2 ton vehicle is just stupid.....if it gets into a snake you simply wont have enough car weight to stop it. The dog needs to be controlling the tail rather than the other way around.

The last time I was stopped by VOSA when towing a caravan (well the Police do the stopping for them). They were doing a basic check to make sure the car weighed more than the caravan.....using "drive over" scales. He said I could be prosecuted under the insecure or dangerous load rules if the van was heavier....that the only check he did....did not even look up my trucks max tow weight! He said the reason they were there was because of a nearby horse show.....nearly every double horse box you see being towed will be over the limit for the car......but since they have to be moved and most horse boxed are towed slowly to protect the horse from injury the VOSA boys are lenient on them......just looking out for the real piss takers. They had stopped one rig from proceeding any further......A twin axle two horse box behind a RAV 4 .....LOL!