1. Keri

    Keri Leader

    I noticed something the other day....
    It suddenly got cold out!

    So I pull on the knob for heat and I get....
    A face full of nice, warm exhaust fumes!

    Oh no. I thought I had a little talk with Comrade Trabi about this homicidal behavior last year and 38,000 kilometers ago.

    When I installed this "budget" heat exchanger I noticed an immediate increase in exhaust noise which I attributed to the thin metal of the heat exchanger acting like a speaker for the exhaust pulses.
    This is especially noticeable inside the car with the heat on.

    So a little preliminary checking revealed that yes, the fumes were emanating from the heat exchanger.

    So, out of the car with it and on goes the smoke machine for finding small leaks. It's leaking at small, barely visible cracks at the inlet and outlet.

    So, I cut the outer housing for warmed air near the inlet and outlet and folded it back.
    The outlet cracks were easy to weld up but not the ones by the inlet.

    So I came up with an interim fix until I can get a "premium" Vorschälldamfer.
    I merely cut away the outer housing so that the cracked area will not leak into the warmed air, leaking into the underhood area instead.
    A little creative bending, welding and a bunch of exhaust sealer to keep any leaks out of the cabin air and back into the car it goes.

    And... all the way home, nice fresh hot air with no nasty headaches, passing out or dying from CO poisoning!

    So... why would a relatively new heat exchanger do this?

    Well, the the thin metal prone to vibrating apparently fatigued and cracked.

    It's also possible that I had the manifold-to-heat exchanger bolts too tight. This could cause either more motor vibration to hit the exchanger or the weight of the exchanger to cause the inlet side cracks.
    Perhaps a little "give" at this joint would reduce stress on the exchanger, so I'm probably not going to tighten the new one quite so much.

    JASONCHAD Trabi Meister Forum Donor

    I need to get mine out of and try the heater too...it is getting cold here in Idaho...BTW, the clock in still on my desk at work and is keeping time nicely!
  3. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I inspected my "elbow" the other day to see if the baffle had collopsed. Looks like the inside of a glass pack muffler. Warm air comes out the floor vents but the velocity of the air still sucks unless I'm running wide open and still it's nothing to write home about.

    I was hoping the hose clamps on the short rubber hose might create a better seal help but didn't seem to do much good.

    As soon as I can find the correct size silicone reducers I'm going to mount my brake cooler fan in place of the short rubber hose to boost the air flow.

    Otherwise I can't find any air leaks in the system.
  4. TNTrabi

    TNTrabi Lord Trabi Forum Donor

    Have you taken off the motor blanket and metal shroud to inspect the small hose in there that directs air into the heating system? It may be in bad condition or missing, in which case little air is being fed into the heater.
  5. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I do know the short hose has a split in it where it slides over the snout and I "repaired" it with electrical tape while it was still on the car.

    I was going to remove it and wrap tape around the end of the hose (or just got to Advance and get a radiator hose) but seems to me the only way to remove it is to first remove the fan assembly. But never thought about removing the shroud. That might be easier. I'll check on that.

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