Air ducts (83)

Air ducts

Mercedes Ponton air ducts during the final assembly of the car 2018

The air ducts during the final assembly of the car 2018

The air ducts are made out of card board and is often found damaged by wear, tear, moisture, heat, dirt and leaning elbows. Buying new in descent shape is expensive. From MB you can buy new ones made of glass fibre, they are not cheap either. My air ducts had also seen their better days but in my opinion worth saving. What you see below is my version of the restoration instructions found on the Mercedes-Benz Ponton PageMercedes-Benz Ponton Page

We take if from the beginning. The first picture shows you one - I think it is the left - with markings from someone's elbow, probably leaning on it trying to remove plugs or adjusting the distributor. Both were carefully sandblasted and repaired with papier mache according to the instructions from the Ponton pages. The papier mache was from a recipe based on boiled, hand-torn strips of newspaper, white glue, chalk and linseed oil. The result was much harder and durable than I could have imagined. It was a pain in the b... to sand it down to the correct shape.

Air ducts for a Ponton being restored

Air ducts for the Ponton being restored at the lake Eklången

The air ducts were thereafter painted inside out (soaked) in a thin mixture of a marine 2k epoxy primer, Hempel Light Primer 45551, hopefully giving it good moisture protection. Then they were puttied and sanded a couple of times before I thought they were ready for the final protection and last - but not least - the semi-gloss black paint (fifth and sixth picture). From the fourth picture you can see that I tried to make this boring work as nice as possible, at our country house at Eklången, close to Eskilstuna. Unfortunately the black paint showed some bad spots so on with some more putty and back to the sandpaper. And then we came to the status shown in the last picture.

  • Unrestored Ponton air duct
  • Unrestored Ponton air duct
  • Air duct reparations with papier mache
  • Air ducts for the Ponton being restored at the lake Eklången
  • Air ducts soaked in a thin mixture of Hempel Light Primer
  • First paint of air ducts with semi gloss black
  • More putty
  • Final layer of semi gloss black on Ponton air ducts


Coming so far I turned to the assembly of the flaps. One advice I can give you before you give the air ducts their last, semi-gloss black paint; try the flaps so that you haven't used too much papier mache somewhere... I started the adjustments with a lot of sanding on the inside but it was a scary experience since I didn't want to risk to crack the finished outer surface. Instead I went for another solution which is to smooth the edges of the flap instead. It was certainly easier, gave more control and gave a better result. Then we got some detailing to do. In order to seal the flaps, otherwise they're not tight enough against the sides of the boxes letting air into the coupe, you use felt. In Sweden you can find the exact type and thickness (3mm) at Panduro Hobby. 

  • Flaps for air ducts before restoration
  • Restored Mercedes-Benz 219 flaps
  • Need to adjust air ducts after installing flaps
  • 3mm felt to seal flaps
  • Felt installed in air ducts
  • Felt installed in air ducts
  • Flaps assembled in Ponton air ducts
  • Flaps assembled in Ponton air ducts

Insect screens

The same type of felt is also used on the underside of the insect screen. Note here that the second picture of the insect screen points to that it wasn't black but probably white cad. My white cad finishing actually was very bad due to bad preparation from my side. Looking at other cars I decided that semi-gloss black would probably be ok too... Inside the tightening strap for the air duct you use a 1mm felt. 

  • Insect screens before restoration
  • Insect screens before restoration
  • Ponton insect screens restored and their felt
  • Ponton tightening straps restored and their felt
  • Gluing felt in tightening straps

Heat exchangers (83)

Mercedes Ponton heat exchangers during the final assembly of the car 2018

The heat exchangers during the final assembly of the car 2018

The heat exchangers were dismantled. When I blew them with compressed air I had a large pile of yellow/black crud on the floor. They had probably not been restored since new. The radiator guy wanted almost 200USD (year 2002) for cleaning and pressure test them. Since there isn't a shortage of used heat exchangers on the market I decided to try do this restoration myself. A failure wouldn't cause an expensive problem (for once...).

  • Ponton heat exchanger before restoration
  • Ponton heat exchanger before restoration

The workshop manual says to pour 5% P3-Lye into the cooler and then drive around for a day. I haven't found out what P3-Lye is or where to get it so I went for caustic soda instead (100% Sodium Hydroxide). To drive around for a day was something that I really would have liked to do - if it had been possible. Instead I boiled the heaters for four hours in a mixture of caustic soda, shaking them each 10-15 minutes and changing the caustic soda three times. The first time I was afraid of the consequences of boiling the heaters in lye so I took only 2-3%. Nothing corrosive happened so the two last times I used a mixture of 5%. Between each time I rinsed them thoroughly, shaking them to get all the oil and crap out (and that was a lot) etc, etc...

Do not forget to use protective glasses and gloves! And if you decide to try my method; note that the caustic soda is highly aggressive/corrosive to aluminium, the material that is used in for example the Ponton's cylinder head!! So rinse the heat exchanger thoroughly before connecting them to the coolant system again! Above all, you follow my procedure on your own risk!

After all the travels and work the car got a total wash 2016

After all the travels and work the car got a total wash 2016

Now when they're clean it was time to go for the limestone. First they had two water baths with vinegar to neutralize the lye and then I let them lie in a new, fresh mixture of water and vinegar over-night. Observe, it's no use doing this before having cleaned the heaters. Vinegar can't get to the limestone under layers of fat, oil and crud. I probably had 3-4 table spoons more of limestone gravel loose from each unit during and after this process!

  • Cleaning Ponton heat exchangers with caustic soda
  • Removing limestone from Ponton heat exchangers with vinegar

After this they were like new when I looked down the regulating valve. Of course, I can't say anything about how the elements look like further down but I doubt - based on everything I got out of them - that there is anything wrong with them now. So, time for the next activity; pressure check. 

I bought a set of rubber hoses (actually hydraulic hoses which made the purchase unnecessary expensive). The set consists of two hoses, fitting the lower connection and the regulating valve respectively. One of them got a nipple for a bicycle pump with an air pressure gauge. The other one was open so that I could check if the regulating valve was air tight (the hose is of course supposed to be under the water in contrast with what the second picture shows). With a bicycle pump the test is of course rather inexact but I don't think it matters. If I remember correctly, the system is to be able to be tested at 1,6 bar, I used 2-3 bars. I found only one leak, one of the lower connections was bent which obviously had caused a crack. I bent it back and soldered it = fixed. Beside of that everything was 100% tight! So, instead of paying the equivalent of 200USD I reached 30USD - the hydraulic hoses taking most of that cost - and a couple of interesting hours. The following picture shows you the rest, cleaning, painting and assembling.

  • Pressure check Ponton heat exchangers
  • Pressure check Ponton heat exchangers
  • Solder leaking heat exchangers
  • Cleaning the outside of heat exchangers before paint
  • Heat exchangers painted with semi gloss black
  • Completely restored Mercedes-Benz 219 heat exchangers

Heating and ventilation (83)

After all the travels and work the car got a total wash 2016

After all the travels and work the car got a total wash 2016

These pages will show you the work on the Ponton's heating. As usual I won't cover the whole process and all the parts here, mainly those that shows what I did on a general level as well where I had problems or where I think my ideas and pictures can be of any help to others.

The restoration of the different parts of the heating system can be found in the sub menus under Heating and ventilation. Enjoy everything!

See also the article Engine cooling (to which also the group "Radiator" has been moved).

Blowers and regulation flaps (83)

Mercedes-Benz 220a, W 180 I, © Daimler AG

Mercedes-Benz 220a, W 180 I, © Daimler AG
As the 219 it doesn't have the 220S/SE's chrome lists along fenders and doors but the 220a has the long chassis and hence a divided rear door window. Same engine as the 219 but with double carburetors, not a double carburetor.


Not much to say here than "before, during and after restoration". Note the small rivet that fix the wings/rubber mountings for the blower motor to the surrounding white cad'ed "house". This "house" is in its turn fixed to the outer, black ring with three screws. The fan blade is secured to the axle with a small pin bolt. The motor was cleaned, checked for functionality and the two "bearings" inside each lubricated. I was actually rust inside the motor housing due to inadequate drainage. I drilled two more holes and had some Dinol ML in them. The rubber mountings were glass beaded, cleaned and then soaked in liquid paraffin for a couple of days.

  • Blowers before restoration
  • Small rivet that fix the wings in the blower
  • Completely restored, but not yet assembled, Ponton blowers

Regulation flaps

These pictures don't say much, I'm only very satisfied with the end result.

  • Regulation flats before restoration
  • Ponton regulation flats restored and assembled