Thom --
Don't know what the weather's like where you're at, but... I'm surprised
that you don't have the sickly sweet smell of anti-freeze. You can look
under the heater box by opening the front hood and see if any green ooze is
coming out. You might also try to capture some of the 'steam' in a white
facial tissue for color analysis.
If not, and you're where it's humid -- and you have your A/C on -- then you
could have a low refrigerant charge. A low charge will cause 'frosting' of
the evaporator core and a cold steam like mist to be discharged from the
dash vents. Check your refrigerant charge by looking at the
receiver/dehydrator to see if the sight glass is full.
Usually, the thermal limiter fuse on the A/C compressor will blow next, or
the low pressure switch will prevent the compressor from engaging. That
depends on your coach year. Try putting the top lever in the vent position,
which turns off the A/C compressor. See if that stops your steam.
Not as likely, but a hole in your A/C evaporator will also cause refrigerant
oil to be forced out. It can look like steam too and not have an odor but
feel oily. Again, this problem wouldn't last more than a few minutes before
the A/C system lost its charge.
Beyond that, there isn't much that can produce steam. A hole in your
radiator could also be producing engine compartment moisture or steam that
gets picked up by the heating system fan. You should be able to find that
pretty easily with a visual inspection.
Keep in mind that If you're using the new environmentally friendly
anti-freeze solutions, they don't have as much stink as the older
formulations.
On a remote chance, it could be the windings in your A/C fan burning out,
but you'd have the enticing aroma of burning electrical wiring along with
the smoke. Let us know what you find, this is an unusual problem!
Mark
> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto
wner-gmcmotorhome]On Behalf Of Thom Hole
> Sent: Thursday, January 07, 1999 2:43 PM
> To: gmcmotorhome
> Subject: GMC: GMC Dash Heater Problems
>
>
> 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??
>
Don't know what the weather's like where you're at, but... I'm surprised
that you don't have the sickly sweet smell of anti-freeze. You can look
under the heater box by opening the front hood and see if any green ooze is
coming out. You might also try to capture some of the 'steam' in a white
facial tissue for color analysis.
If not, and you're where it's humid -- and you have your A/C on -- then you
could have a low refrigerant charge. A low charge will cause 'frosting' of
the evaporator core and a cold steam like mist to be discharged from the
dash vents. Check your refrigerant charge by looking at the
receiver/dehydrator to see if the sight glass is full.
Usually, the thermal limiter fuse on the A/C compressor will blow next, or
the low pressure switch will prevent the compressor from engaging. That
depends on your coach year. Try putting the top lever in the vent position,
which turns off the A/C compressor. See if that stops your steam.
Not as likely, but a hole in your A/C evaporator will also cause refrigerant
oil to be forced out. It can look like steam too and not have an odor but
feel oily. Again, this problem wouldn't last more than a few minutes before
the A/C system lost its charge.
Beyond that, there isn't much that can produce steam. A hole in your
radiator could also be producing engine compartment moisture or steam that
gets picked up by the heating system fan. You should be able to find that
pretty easily with a visual inspection.
Keep in mind that If you're using the new environmentally friendly
anti-freeze solutions, they don't have as much stink as the older
formulations.
On a remote chance, it could be the windings in your A/C fan burning out,
but you'd have the enticing aroma of burning electrical wiring along with
the smoke. Let us know what you find, this is an unusual problem!
Mark
> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto
wner-gmcmotorhome]On Behalf Of Thom Hole> Sent: Thursday, January 07, 1999 2:43 PM
> To: gmcmotorhome
> Subject: GMC: GMC Dash Heater Problems
>
>
> 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??
>
