GMC Dash Heater Problems

[thom hole]

Well, today's challenge is a new one for me. I've got a small amount of
what appears to be steam coming out of the dash vents. It doesn't smell
like anti-freeze, in fact it doesn't have any smell at all.

I changed the heater A/C controls and that had no effect. It goes away
when accelerating and is the heaviest when coasting.

Any thoughts or experiance out there??

 

[thom hole]

North Carolina!! Air temp 45 degrees, sunshine!! Started with heater,
but when I saw the 'Steam' I changed the dash controls to other positions
to see if it would stop, which it didn't. Driving at 50 mph, it's about
the amount that would come off of a freshly poured cup of McDonalds coffee.
Gets worse on coasting from 50 mph with foot off accelerator.

>In a message dated 1/7/99 1:49:18 PM Central Standard Time, THHOLE
>writes:
>
>>
>> I changed the heater A/C controls and that had no effect. It goes away
>> when accelerating and is the heaviest when coasting.
>>
>> Any thoughts or experience out there??
>>
>>
>Thom
>
>Where are you? Is it cold where you are? Is it hot. Are you trying
>to use the heater or AC?
>
>Take Care
>Arch 76 GB IL
>

 

[larry dtimothy]

> ...small amount of what appears to be steam coming out of the dash
> vents... It goes away
> when accelerating and is the heaviest when coasting.
> Any thoughts or experiance out there??

Of course first thought is to look toward Vacuum related parts.
Timothy