having just bought a Def 90 1993 127k miles. The heater/cooling is pants. i saw somewhere on here that a flush through is required. I'll do that ( if pos).
is there an upgrade of some sort available to fit?
Allisport do an upgraded heater matrix. A few people have also fitted a bilge fan in line to get a better flow.
You can also get a kit to install in the dash to direct some air flow to the side of the dash to clear the side windows.
There are a few seals here and there that can give up too that will mean your air flow goes to your feet as well as the windscreen.
You'll probably find that just sealing the system makes a massive difference. Most people overlook it when trying to improve the heating and instead focus on the heater matrix itself. The heating in my 1996 110 is brilliant
Yes this is the way to go.
You can link the flow and return pipes together on the top of the engine to keep you going.
I fitted new seals to the inlet from the wing and the outlet to the bulkhead as well as around the edges of the heater matrix and on the sufaces of the flaps.
Mine works so much better now, from useless to really good.
The box is riveted together so you need a good, sharp drill and a couple of handsful of rivets to put it back together.