what car is it?

It used to be the case when cars had mechanical fans (ie on the end of the crankshaft) but with electric fans there's normally enough airflow at low speeds to keep the engine cool.

I dont see why, most cars have electric cooling fans, so the additional loads created by towing will just mean the fan runs more often.

Current E Class estate, was being re coded this morning and was told MB recommend it done. Then the word warranty was used. It's also mentioned that it might need doing in the online tech manual.

Depends on what you're towing and the weather conditions you'll encounter when towing.

My old Citroen BX, was upgraded to two fans due to the loads it placed up on the engine, but my current Kia Sedona doesn't give two hoots and hardly ever comes on even when towing at its 2T max capacity, nearly 5T train weight!

I've emailed Merc's tech department to ask, but I suspect it will need doing. The MB kit would be around £1500 inc fitting so suspect that would include a new fan.

£1500 quid ??

I assume that includes a reach-around and a post bumming cuddle ?

I fitted a complete electric fan kit to my Defender and that was expensive at £140 + a little skin from my knuckles.

What engine for your E class? If one of the bigger engines, then unless you're frequently towing in excess of 1000kg over the Stelvio Pass I can't see it's a problem.

Seems like a nice money earner for Merc. How on earth can they produce a car that needs an extra fan just to tow something, the phrase "not fit for purpose" springs to mind.
Why dont you try towing something and see what happens to the engine temp? If it gets too warm then you know it needs extra help.

[i]Why dont you try towing something and see what happens to the engine temp? If it gets too warm then you know it needs extra help. [/i]

problem is that the ECU will also record the temperature and if there's any engine problem later on then Merc will duck out the warranty claim saying that the car didn't have the right fan and overheated...

problem is that the ECU will also record the temperature and if there's any engine problem later on then Merc will duck out the warranty claim saying that the car didn't have the right fan and overheated...

Anyway, we're not talking boiling the engine, just seeing if the temp gauge goes over the normal position.

Spud, what are you planning on towing?

I've emailed Merc's tech department to ask

[i]the ECU doesn't know if there was something on the back when it overheated and it could have been in normal use[/i]

probably depends on the wiring - if it's Can bus based then it might well detect additional bulbs/load etc and record when they're connected.

But the ECU doesn't know if there was something on the back when it overheated and it could have been in normal use.

I believe it does, actually. My LR certainly does.

The ECU does know if you are towing since hooking up changes the stability programe too.

Spud what engine do you have in your E class and what are you expecting to tow? I can't imagine mine with +400lb of torque overheating!

Well a quick google shows that it seems a Merc can't tow something without an uprated cooling fan which I find surprising nowadays. I still believe its a good excuse to rip more money out of you though.
Defo not going to get a Merc now then.... not that I was anyway 😉

It's the 250 CDI so 2143cc with 204bhp. Towing a 1500kg caravan, 79% of kerb weight. The issue is also the coding will know when it's been towing etc as it is programmed to adjust the engine etc.

Put it this way: if you've got a cooling system designed to deal with you driving your two-tonne E class flat out on the motorway, then gentle pootling with a trailer will be fine.

Obviously if you're planning on driving at 120mph+ up a long incline whilst towing the maxiumum load (in 45 Centigrade) you'd put some strain on the cooling system, but for all normal purposes you'll be fine.

Spud the E250cdi has 370lb of torque. That should be plenty enough for towing in the UK? It sounds like another MB means of extracting money from you.

Asking MB how much to fit a towbar in the first place was a "are you sitting comfortably moment"!!

The issue is also the coding will know when it's been towing etc as it is programmed to adjust the engine etc.

Does it really? What if you put a bike rack [with lighting board] on the towbar? Does it adjust the engine then?
What does the owner manual say regarding towing? If it says that you must upgrade the cooling system if you're going to tow then maybe you should. But if it doesn't then there's jack that Merc could do even if it did overheat .... which it won't.
Did you buy the car knowing you were going to be pulling a caravan?

Sounds like they are taking the wee. My Passat doesn't care if it's towing. When it's working hard doing 60mph there's a 60mph wind going through the radiator which is obviously more than any fan can produce.

When you're going slowly and there's no airflow is when you need a fan, but that's when the engine's not working hard. Sounds like rubbish to me. Unless your car has a dodgy cooling setup somehow.

BUT

If it's in the warranty I don't see you've got much choice.

Hang on a minute though - isn't yours an auto? Fluid based torque converter autos need extra cooling when towing since the oil's part of the drivetrain and it gets hotter. However you'd expect a nice modern motor like that to have some kind of lock up...

Email back from Merc's EU tech department and it does need uprating! FFS! It is an auto, yes, so I imagine there's a good reason for it. Not worth stuffing up my warranty on a bloody expensive car. Grrr! This ****ing caravanning is expensive 😉

This ****ing [s]caravanning[/s] Merc is expensive

FTFY 🙂

First I've ever heard of a car needing a new fan...

Hmmm £1500 - how many trips to a decent hotel does that buy?

Sell the carvan and don't be a "shed puller" 🙂

Email back from Merc's EU tech department and it does need uprating! FFS!

DO be a shed puller! Teach these Clarksonites how to relax on a road!

Thanks Mol! Yes it's the car not van. What can I say, tech and manuals say it needs it. From my point of view I explicitly asked sales about towing. Queue snotty email to the dealership. I ain't risking my warranty. Just grates. And for the record Audi state the same apparently.

Yeah if the dealer didn't tell you they are being.. well.. car dealers.. and hence gits 🙂

However the VW dealer did tell me not to have them fit the towbar cos it was £600 and could be had much cheaper elsewhere 🙂

Sinclair VW in Cardiff btw - good dealer.

We've towed our 1500kg Challenger with a 130hpTDCi Mondeo & 130hp TDi Galaxy, & I dont think I've ever heard the fan come on on either one of them. They are taking the piddle. Christ, you could buy a TDCi Mondeo for less than the cost of your cooling fan. 🙂

sharkbait - Member

Email back from Merc's EU tech department and it does need uprating! FFS!

Did you actually expect them to say something different? Once again, does it say anything about it in the towing section of the owners handbook?
Maybe they put rubbish cooling fans on them when new to save money. Now if you'd bought an Volvo, Audi, etc you wouldn't have this issue.
I'd still try towing without the upgrade first - it's not like you're daft enought to actually let the car overheat.

Thats not true. I have an xc90 and in the owners manual it states that if you are towing and have the 2.9 petrol then you need to fit an extra oil cooler for the transmission (which is what i expect the merc one is for).
The extra cooling for when towing up long hills and the speed dropped but the engine is working hard, not htat we have many of these types in the uk. My manual also advise using the manual over ride when going down these hills to stop the brakes from over heating.

i agree with owenfracknell - I suspect the issue is with the auto gearboxes rather than engines themselves. You're likely to be pushign a lot more torque through it at lower speeds when towing a 'van.

part of the cost will be for fitting/increasing the size of the autobox cooler, otherwise it'll cook its atf/fancy techno wonder fluid.

Cheers for the helpful posts, I suspect they're covering themselves. Parts said it was common on many MB models. Like it or lump it. Still not going to stop me sending an email to the dealership.

A colleague of mine was told the same drivel by Audi, I regularly tow a Horsebox with my measly 128BHP 2009 Toyota Avensis estate loaded up with horsey stuff and people, never had a problem. If you had an issue with your car and they pulled out the 'you've been towing' trump card I'd happily have it out with them, just Germans wanting to protect their premium marque from niggles by over engineering a solution that isn't needed.

Sounds to me like it's really transmission oil cooling, not engine cooling - different thing altogether.

You people are mostly talking about manual gearboxes, or gear driven autos like the DSG.

Best not call it drivel eh? 🙂

Just have to wait for the part now, bit of a bugger as collecting the caravan next Friday!

I'd be asking if they've sold me something which is 'not fit for purpose'

Thats not true. I have an xc90 and in the owners manual it states that if you are towing and have the 2.9 petrol then you need to fit an extra oil cooler for the transmission (which is what i expect the merc one is for).

Really? 8O.
I'd better get my manual out then as I've had my xc90 for 9 years and didn't know that! I'd also bettr tell my mate who's been towing his big caravan for the last 3 years with his XC90, and I know he hasn't got an extra cooler either!
In that case I take everything I said up there ^ back. 😳

the xc90 especially with the 2.9 petrol has a really crap auto box made from cheese, it stopped me from buying one, even the AW box in the D5 isnt much better and again really suffers from overheating when towing and must be fitted with the bigger autobox cooler.

Adding additional cooling for the auto-box use to be the norm, but tbh I just assumed it had gone away...

FWIW my better half tows (box and 2 horses etc) with her auto Freelander, and that needed nothing doing.

Yep, molgrips has it. When towing Auto oil can get too hot, oil performance degrades and prematurely wears the clutch packs in torque converter autos.

Email back from Merc says engine can overheat and hence needs extra cooling. Anyway have it in black and white. All the references I can find only state might need extra cooling, so perhaps is down to the transmission.

But the ECU doesn't know

You'd be amazed what the ECU can tell you!

My ECU tells me not to buy an auto if you plan on towing !

It also says just get a Landy for your £1500 and job done !

Honestly, the manufacturers just ass cover and make things difficult in the name of advancement. I do hear Mercs don't even have a dipstick these days. God help owners of one in ten years time.

FWIW my better half tows (box and 2 horses etc) with her auto Freelander, and that needed nothing doing

I also thought that most fluid based autos already had oil coolers nowadays.

It also says just get a Landy for your £1500 and job done !

Lol! You mean £1500 per year don't you?

Had a look in my xc90 owners manual and itnsays that an oil cooler can be fitted if required bur it's not a 'must'.
Also says that if the gear oil heats up too much the car will be put into limp mode, in which case you should stop the car and allow the box to cool before resuming your journey.
I would imagine Merc would have a similar system.
Not sure about the cheese thing with xc90s though.

Having stuffed an auto transmission by towing, and the car just months out of warranty, I'd suggest the OP does what Merc tells him, whether others think its 'necessary' or not. I count myself lucky that Toyota agreed to give me a new transmission, and I just paid the labour to fit it.

£1500 for a fan? What utter bollocks. Your car has been designed to cope with the hottest possible conditions without overheating - do you know there are Ro-ro ferries shuttling between Rotterdam and Lagos every week carrying hundreds of second-hand Mercedes cars to West Africa where they are highly prized for their ruggedness? Nobody modifies the cooling system or fits fans, your dealer is taking the piss. A fan kit costs about £200 anyway.

Having stuffed an auto transmission by towing, and the car just months out of warranty, I'd suggest the OP does what Merc tells him, whether others think its 'necessary' or not.

Yes, but the OP is saying that Merc are saying the engine needs extra cooling and not the transmission - this is what's rather odd.

What utter bollocks

Hmm, I'd bet that there's more to it than just a fan. My money's on the extra cooling being an oil cooler, as above. Did you read the thread?

I believe that several cars need this doing to maintain the warrenty. I understand a couple of years ago the Caravan Club did a list of cars that required upgraded fans for towing. Apparently it is cost saving that they reason that not many of the cars need as big a fan for cooling as they won't be used for towing. I drive a Freelander and tow a 1500kg caravan, no need for an upgraded fan as LR believe most of their cars will be used for towing1

Spud, good luck for the weekend, hope everything goes ok!

I think this will be a suitable solution to your problem.
It will also help out the rest of us who have to use the roads.

Why are caravans a problem on the roads glenh? Unless you were the sort of person to get wound up about having to drive 15% slower than otherwise... Can't imagine what kind of angry bundle of road rage would get upset about that....

I think this will be a suitable solution to your problem.
It will also help out the rest of us who have to use the roads.

I quite often get a call from my mate when he's towing his caravan (because he's bored) and when I ask him what the traffic's like he always replies "the roads are completely clear in front, but you should see the carnage in my mirrors!"
🙂

Leaving BBB on the Sunday afternoon was the first time I'd towed on single carriageway roads with cars around. I picked up a tailback after a mile or so and I was very proud to pull over immediately.

£1500+ is what it would cost to retrofit an MB towbar kit to the vehicle, more probably as the kit is £1036 plus 5 hrs labour.
At least when the fan is fitted I can drive along safe in the knowledge that when I'm slowing up traffic on the way to the West Country I won't overheat! 😉

molgrips - Member
.... 15% slower...

Yeah right 😆

"Not sure about the cheese thing with xc90s though"

the 2.9 petrol XC90 has a reputation for weak autoboxes-its due to the packaging constraints of the engine size that forced Volvo to use a physically smaller GM sourced box that was a weak design beforehand, coupled with the torque of the 2.9 resulted in a lot of failed boxes.
The D5 limits torque in 1st and 2nd gears to help the problem although it is fitted with an Asain Warner box which is better.

All Volvo's with the 5spd autoboxes have issues though in the fact the autobox fluid is rarely changed and is an expensive non-Dexron type oil as a result they struggle to see 100k+ miles. Pull the box dipstick-the fluid should be red, if its discoloured and smells burnt-get it changed. But read up before hand how to do -and do not use standard ATF or you will kill it straight away.

Similar to Mitsubishi VR4 autos then. Quite a few of them use Amsoil ATF in those works a treat and tends to improve the shifts immeasurably!

Whilst we are (not) on the subject of caravans, I crossed the footbridge by mine today which I practically never do, and happened to notice that the skylight is missing! Wtf?

We've had loads of rain lately too 🙁 Had to go and get a tarp double quick, but I fear the worst, that my caravan is even more shagged than it already is 🙁