Welding, expansion tank and new custom heater

In this blog post a summary of the activities of recent times. I will write a blog post a little less often and instead post more photos on Instagram and my Old Volvo Facebook page. So follow me on Instagram: @oudevolvo and/or like my OudeVolvo Page on Facebook. These photos are also on my front page.

Welding trailing edge

In the design of my rear battery box, I still had to make a good connection to the car. With my car, that part was completely rotten. With my father’s car I saw that there is a profile in it, so to make sure that the box also fits his car, I have to take that into account.

achterpaneel combi origineel

Fortunately, I had kept exactly that part of my sheet metal donor combi .reparatie achterrand

So neatly freshly made and put in the zinc primer.

achterrand zinkprimer

And then welded into it.

achterrand erin gelast

Overhauled 3.99 rear axle

I also bought a wagon rear axle with 3.99 ratio. This has been used since a total overhaul 8000 km so definitely still good.

3.99 combi achteras gereviseerd

Because I bought my combi in non-driving condition, I don’t know if that rear axle is good at all. An additional advantage is the other transmission, 1:3.99 instead of 1:4.56.

Expansion tank cooling system batteries

In my blog post about the dimensioning of the cooling system , I already wrote that I had found a nice compact expansion tank from a V70. However, it was not compact enough to be able to place it at the highest point in the cooling circuit of the batteries. So I continued searching on the Internet and on the local scrap yard.


In the cold had a lot of hoods open, but many were either already empty or too large and then mainly too high expansion tank. Interesting was the Alfa Romeo 145, but the best options seemed to be an expansion tank from a Volvo 440.

Afmetingen expansievat 440

Or a power steering oil reservoir from a Daewoo Matiz.

stuurbekrachtigingsoliereservoir Daewoo

But at that time I did not have enough insight into the exact available height so I went back to measure properly and make a dummy.


With that, on an even colder day, we went back to the junkyard.

autosloop in de sneeuw

Had a few more hoods open, including that of a Volvo 940, but in the end those two I had already seen seemed to be the best. So both the reservoir was taken out of the Volvo 440.

expansievat volvo 440 eruit

As from the Daewoo Matiz.

stuurreservoir Matiz eruit

And that of the Volvo 440 fits perfectly after removing the original mounting on the bottom.

expansievat past

Thanks to Ben van Tinustuning for thinking along about the design of the cooling system itself and optimal location and configuration (overflow vs expansion and whether or not highest point or with air vent). And he also had good tips for the heater and blower issue.

Heater and blower layout

In my previous post I had just cut out the support of the DC-DC converter because I couldn’t fit it in together with the heater. The newest idea was to put the DC-DC converter at the bottom, so I started working on that.

The most important question then became: Where should the blower be?

blower rechts onderaan
At the bottom right and then with tubes into the heater.
blower naast bak
Next to the batteries box, but that’s tight with expansion tank and cables.
blower onder bak
Under the batteries box and work with tubes again.

And an option that was a bit more difficult to try was only drawn for a moment.

blower boven
At the top in the suction hole of the original heater.

The disadvantage of that option is that you suck in the fresh air high and can therefore be relatively warm in the summer. In addition, it is very tight. At the same time, that is the best thing in terms of airflow and placement. So first let’s see how it came out in terms of further components, so a heater housing was put in.

kachekhuis zetten

And put together and that worked out pretty well.

PTC element erin

So I took the plunge and grabbed the grinder. I still had to remove a bit more than hoped, but the blower is nice.

blower heeft een plekje

The advantage of that place now also appears that I can put a recirculation valve in it.

So from there close the hole in the bulkhead and provide a mounting place for the blower.

dichtmaken schutbord

And then you can no longer press the blower into the hole from below, so I had to remove just a little more above the blower. But to get rid of that edge and bring back the original look, I reuse part of the old heater as a cover.

hergebruik oude kachel

Inspiration visit New Electric

Finally, I visited New Electric for some more coordination and consultation and immediately gained a lot of inspiration and ideas.

New Electric bezoek

Next year with fresh energy! Happy holidays and a happy New Year.

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OldVolvo is a classic Volvo hobby blog by Lars Rengersen.

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