Steam from defroster vents - The 1947 - Present Chevrolet & GMC Truck Message Board Network

lmac1210 · 07-03-2010, 07:11 PM

I have really enjoyed looking over all the posts over the last month or so.

I just got a 1970 GMC with an 8 cylinder and 3 on the tree has been converted to floor shift. I finally got her running and took a drive around the block. When I got back from the short trip I noticed that steam was beginning to blow in from the defroster vents on the top of the dash and I heard a bubbling sound. I got out and raised the hood and noticed there was water running out from the bottom hose on the heater core box. Is there a chance this is just a bad connection at that hose or does it sound like a bad heater core. I also noticed some dripping from somewhere near the bottom of the radiator. It has been a long day so I just parked it and knew I could possibly get some help on here. Thanks for any suggestions or help...I am only a beginner when it comes to working on mechanical stuff.

ERASER5 · 07-03-2010, 08:10 PM

Yea, there is a chance that it is the connections, a small one, but a chance. What do have to lose? If it is the core, the hoses have to come off anyway.

brenthiggins · 07-03-2010, 08:26 PM

Get you a heater core and go to work. Not that big of a deal and save yourself some time.

**Stocker** · 07-03-2010, 08:40 PM

Quote:

Originally Posted by brenthiggins

Get you a heater core and go to work. Not that big of a deal

Depends on whether you have factory A/C or not!

lmac1210 · 07-04-2010, 10:37 AM

Thanks...I will try to get something accomplished with it today.

GASoline71 · 07-04-2010, 11:09 AM

The heater cores on these trucks are very accessable as the box is all in engine bay. Also the cores aren't very expensive either. However... as Stocker pointed out... If you have AC... it won't be as EZPZ as without AC.

Gary

cdowns · 07-04-2010, 11:16 AM

it's a good project to do to remove the core and clean out the haeter box of 40years of debris// easier to do in summer than in winter

GASoline71 · 07-04-2010, 11:39 AM

When I did mine 4 years ago... There was a mouse nest in heater box. Completely blocking any airflow through the core at all. Which also led to the core rotting out and leaking. The truck has sat in a field for a number of years prior to me getting it. So a lot of years of mouse poop and urine was pretty nasty...

Gary

Longhorn Man · 07-04-2010, 11:40 AM

assuming non a/c, then it is a heater core, no loose hoses. The hoses are outside the box and would drip to the fenderwell then to the ground.

lmac1210 · 07-04-2010, 03:22 PM

Thanks a lot guys!
No A/C, and with today being the 4th my wife is making me do other things than tinker...so hopefully tomorrow I can get at it.

07-03-2010, 07:11 PM	#1
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Steam from defroster vents I have really enjoyed looking over all the posts over the last month or so. I just got a 1970 GMC with an 8 cylinder and 3 on the tree has been converted to floor shift. I finally got her running and took a drive around the block. When I got back from the short trip I noticed that steam was beginning to blow in from the defroster vents on the top of the dash and I heard a bubbling sound. I got out and raised the hood and noticed there was water running out from the bottom hose on the heater core box. Is there a chance this is just a bad connection at that hose or does it sound like a bad heater core. I also noticed some dripping from somewhere near the bottom of the radiator. It has been a long day so I just parked it and knew I could possibly get some help on here. Thanks for any suggestions or help...I am only a beginner when it comes to working on mechanical stuff.

07-03-2010, 08:10 PM	#2
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: Steam from defroster vents Yea, there is a chance that it is the connections, a small one, but a chance. What do have to lose? If it is the core, the hoses have to come off anyway. __________________ '70 GMC C1500 LWB Power disc brakes. WooHoo! Posi 6 Lug Dana 60

07-03-2010, 08:26 PM	#3
brenthiggins Registered User Join Date: Jun 2010 Location: Clemmons, North Carolina Posts: 13	Re: Steam from defroster vents Get you a heater core and go to work. Not that big of a deal and save yourself some time.

07-04-2010, 10:37 AM	#5
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Re: Steam from defroster vents Thanks...I will try to get something accomplished with it today.

07-04-2010, 11:16 AM	#7
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Steam from defroster vents it's a good project to do to remove the core and clean out the haeter box of 40years of debris// easier to do in summer than in winter __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-04-2010, 11:40 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Steam from defroster vents assuming non a/c, then it is a heater core, no loose hoses. The hoses are outside the box and would drip to the fenderwell then to the ground.

07-04-2010, 03:22 PM	#10
lmac1210 Registered User Join Date: May 2010 Location: Harlem, GA Posts: 72	Re: Steam from defroster vents Thanks a lot guys! No A/C, and with today being the 4th my wife is making me do other things than tinker...so hopefully tomorrow I can get at it.

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