Webasto heater(s)

  • Question to the technical amongst us,

    On the rear edge of rhs drivers door I have 2 decals for Webasto heater(s). Are there really 1 heaters ? If so where/what is the second as there is only one for internal heating and how does one switch it on/off ? Photo of the decal posted in pictures.

    After a 10 mile drive this am I parked and on opening the door noticed a small cloud of smoke from under the rhs. As I had not had the internal heater on I wonder where the smoke came from ??


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  • Not responding as one of the 'technical amongst us', far from it, a laughable thought, but a similar thing happened to us too in France in Oct. We drove the van off the awning and when I got out I noticed a cloud of smoke coming from under the middle of the van, sort of just behind and between the two front seats. Had the heating on the previous evening, but not that morning. It didn't happen again, but did temporarily alarm us, also, as we drove on, we did hear an odd, unidentifiable sound, a regular sort of hollow 'ploppish' noise, I stopped and encouraged husb to get out and look under the van, but he could see nothing untoward and then it stopped. No repeat of either ever since.


  • Right then :-)

    The Air top 3500 ST is the stand alone diesel heater controlled by the central console or remote fob.

    The Thermo Top C is an additional water heater fitted by VW to assist in a heating of the vehicle coolant, the idea of this is so the cab heats up quicker when cold.

    You will hear the Thermo Top C run down for a few seconds when you switch off the engine, to purge any diesel and to enable cool down.

    It is possible this is where the poof of smoke is coming from.


    This is only a guess so I would advice going to your local dealer if you have any concerns :-)

  • Beat me to it Stephen :-)

    What a shame VW could not have incorporated the Thermo Top with the on board water system.. Hot water on tap :-)

  • Mike & Steve,

    What you say makes sense, the heater warm-up in low temps is very good and indicates some assistance to the cooling system.

    I wish that VW would give a more comprehensive description of the vehicle systems, they do give any detail on this or of the additiona fuses located around the vehicle !!!

    Thanks for your input.


  • Sorry, fingers meant 'do not give' !!??

  • Alasdair..

    Totally agree with you ref the lack tech info on the Cali..

    A tech at my local dealer was going to print off a comprehensive tech info pack.. But just as he was going to give me it was given an allmighty bollocking by the service manager !!!

    Good PR !!

    PS.. You can edit your post if you make a mistake . It will say edit post to the right of the box

  • i take it the thermo top c is automatic or is their any buttons to press?

  • David..

    The Thermo Top C is auto... No manual overide at all

  • this is starting to get annoying, looking through the books the coolant heater is switched page 141 of the controls and equipment. looking on website for the thermo top c again its meant to be switched to allow the engine to be preheated before starting. i know with climatronic if you press the rest function you get residual heat for 30 mins but no mention of how to switch on the top c before starting the engine. it would be nice to know if it comes on when ignition is switched on but engine not running at certain temps or when engine on but if its latter what good is an engine pre heater if engine is starting from cold to turn pre heater on?

    link below for description of top c and air top



  • Its totally automatic.

    Works on the water temp of the cooling system and turns on the heater when it is cold.

    Many vans / trucks and big cars have these.

    Would have been easy to get the cooling system to make hot water tho, with a heat exchanger under the bonnet piped into the cooling system and would warm up the water weather the webasto was on or not. Boats have a similar system on them.

    One thing that i think is rubbish on my cali is that older calis have the tap shower and we dont!

  • Finally found out that the Thermo top c is automatic as paul, mike and steve state, and is basically installed as diesel engines take a very long time to generate excess heat. It comes on at a temp below 10`C (not -10`C). It has two heat settings for cold and very cold. the engine must be started however you can by adaptor kits from webasto to turn it into a pre heater that heats the engine and clear the windscreen with engine off. The reason why vw fitted as automatic instead of a preheater is that to run the heater matrix and pumps etc with engine off is very power hungry and therefore VW decided to fit the other type of heater which was cheaper and easier to fit and run rather than have two heavy dash mounted heater matrixs.

    When its very cold the top c will burn 0.3l per hour for a comparison the engine on tickover draws 0.7l per hour therefore in cold conditions expect heavy fuel use until the engine is warm.

    If you go to say Norway or the alps then the top c will run constantly while engine is on to provide heat for ocupants.

    The coolant heater in my previous post is an extra on the multivan and is an engine preheater. Vw have a funny way of running a business so many different heater must be costly.

    Regrads GI

  • Thanks for the update David. I was very slow on the uptake by not looking up the Webasto website.


  • we drove from a pub to a shop on saterday only took 5min when i got out her in doors said there is smoke comeing out under the van i said could be water from a puddle on hot disc .but it must be the heater thermo.i allways thought that the glow plugs kick in when you open the door to the t5 .

  • drove to london on friday 3hr trip got to camp site turn engine off and pressed the rest button .were did all the heat come from lasted 30mins .happy days .used it when we stop on motor way on way home came back to nice warm van.

  • hi martin it uses the water pump to feed hot water from the coolant to the heat exchanger for 30 mins to get rid of risdual heat, then cuts out before draining the battery. If the top c was used for as webasto say then you could have that running with engine off to clear windows and heat the engine oil less wear.

    I saw on another forum that someone had webasto turn the top c for 250 into a preheater rather than a get hot quicker. depends how cold this winter is going to be.


  • Does anyone know how viable it might be to somehow use the Thermotop C to provide hot water? I know that they use this heater on other camper conversions for this purpose.

    Or has anyone else got any other hot water solutions (not including boiling a kettle or a black bag in the sun ;-) ) ?



  • I don't have a hot water solution I'm afraid, but I do have an internal heater query. On a couple of occasions, our internal Webasto heater has switched itself on for no reason. Checking the overhead control, it was off, and the key fob was not touched. It was not set on the timer. When I then try to switch it off using the key fob, it does not switch off. The only way to switch it off is via the overhead control; to switch it on, then off again. Has anyone else had a problem like this? (2008 4-motion).