Hi Guys, time for my semi-regular mystery challenge to the group. ;^)
I have a 2000 HSK.

It's getting cooler here in CT and I went to turn my heater on the other evening and got only cool air. I'm not leaking fluid either from the radiator, engine or inside the cabin from the heater core itself. The level seems to be where is is supposed to be when the engine is cool. The fan works, all of the different air routing configurations work, and 'AUTO' works.

I recently had the intake manifold gasket replaced this summer, and I was wondering if they might have done (or not done) something to cause this problem. As some of you may recall, shortly after the repairs were done, (about a week or so) the 'check engine' light came on. Nothing has changed in the engine's performance, and I'm presuming it might be the O2 sensors asking to be replaced or cleaned, but as I said, there has been no negative effect on the engine's performance. However, might this be a clue?

I do notice one peculiar thing: As I'm driving along, with cool air blowing on me, when I make a sharp turn, I get the hint of warm air for a second, and then it returns to the cool air. It's like, 'Oh, here it finally comes...' and then nothing. Very odd... Perhaps it's some programing thing? I don't know, but I thought I'd start here for suggestions, and to see if this is a garden variety problem with this make/model, before I take it to a service person.

Thanks in advance,

Den Gleason/Connecticut