Heater Core Goin Out? Window Haze.

[Colo318IS]

Curious if anyone had any insight to the following issue...

Starting about 6 months ago, when I turned on the heater or A/C, the next day I noticed a light hazy film on the windshield and rear window.  Shortly thereafter I quit using the heater due to the weather and my car was down several months this summer, so never ran the AC...the past week or so I've noticed there's pretty much a constant haze on the windows, not terrible, but it is there.  I'd clean it and it'd reappear the next day...to date I still haven't been running the heater so my thought is the issue is getting worse.

I did look in my Bentleys and it said that a constant fog on the windows is sign of a faulty heater core.  I had a buddy with an E30 M3 that had a heater core blow and I seem to vividly recall he had quite a mess on his floorboards inside.  Definitely want to avoid that.

I know Bentley's doesn't cover the M42, but am assuming this issue is transferable...anyone had a similar issue?  Was it the heater core or is it another related component?  Just tryin to nail down the culprit before throwin cash at it.  I tried to do some research, but couldn't come up with much.

Thanks for your insight,

[ak96ss]

Most likely the heater core heading south, it is a bit of a pain to get out without leaking coolant on the carpet, but not impossible.