Interior temperature sensor issue

[JojjecQuelea]

Hi. The interior temperature sensor on my E28 has the loudest sucking sound! I have driven the car for over 180,000 miles and never heard anything like this. Ms last E28 had 266,000 + when it was T-Boned but I never heard this sound. Any ideas?

[Mike W.]

I suspect your ears are better than mine. But... there is supposed to be a flow restricter in there at the intake manifold, combined with a short piece braided cloth covered hose. My guess is it's missing. I didn't realize it had a function when I got mine and threw it away as it looked like it was about to turn to powder, so in reality I had a vacuum leak. But I never noticed a sound coming from it, hence my opening comment.

[Aldo525]

I suspect your ears are better than mine. But... there is supposed to be a flow restricter in there at the intake manifold, combined with a short piece braided cloth covered hose. My guess is it's missing. I didn't realize it had a function when I got mine and threw it away as it looked like it was about to turn to powder, so in reality I had a vacuum leak. But I never noticed a sound coming from it, hence my opening comment.

The "short piece braided cloth covered hose" is OE 64111386446. My car didn't have it and there was a small "sucking noise" in the cabin until I put that hose on below the intake manifold. RealOem calls that hose a "fuel flow reducer" but it is shown on the heater radiator parts.

[e28Sean]

Can confirm that you will hear a sucking noise with that bit of hose missing. It acts as a restrictor.