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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: dan818 on January 10, 2010, 01:35:52 pm

Title: poor heat?
Post by: dan818 on January 10, 2010, 01:35:52 pm
any questions as to why i am having poor heat? has brand new heater core . and 2 month old blower motor. heater hoses are hooked. so one is on intake one is on radiator
Title: Re: poor heat?
Post by: VileZambonie on January 10, 2010, 01:42:08 pm
Have you replaced the thermostat?
Title: Re: poor heat?
Post by: Lt.Del on January 10, 2010, 01:57:03 pm
welcome Dan, the thermostadt controls the coolant temp.   Coolant temp runs through the heater hoses and heater core. Bad thermostadt, either coolant is too hot or too cold.  Spend $5 and get another thermostadt. 

If that doesn't do the trick, one of the heater lines may be blocked.  Feel both lines going into the firewall--they should be checked after truck warms up--one hot (going to heater core), one warm (return).  If one or both stays cold, you have a clog or something.  Ensure coolant level is topped of beforehand.
Title: Re: poor heat?
Post by: dan818 on January 10, 2010, 05:27:17 pm
has new 195 thermostat. with motor that has 2000 miles on it hoses were changed when moter was swaped . temp gage reads second notch. ?
Title: Re: poor heat?
Post by: VileZambonie on January 10, 2010, 06:33:47 pm
Are both heater hoses hot? Does the blend door switch from hot to cold?
Title: Re: poor heat?
Post by: Josh454 on January 10, 2010, 07:03:37 pm
Put your hand on the inlet and outlet sides of the heater core.  You should be able to hold on to them for about 2-3 seconds before they get too warm.  If they do it sounds like it's blend door actuator issue...  Do you have vacuum or cable operated actuators?  I have seen air bubbles cause concerns in the heater cores before too...does the heat get lukewarm or does it stay ice cold?
Title: Re: poor heat?
Post by: dan818 on January 10, 2010, 07:23:12 pm
luk warm . doors are working i just changed the box to a 1987 box and heat is way better .
Title: Re: poor heat?
Post by: Irish_Alley on January 10, 2010, 08:39:25 pm
I would of thought air also