fire-chickens

I have a 1996 firebird Formula and I've noticed that I have really crappy heat, whether it be in the dash vents or on the floor whatever setting it doesn't matter, i even try the re-circulate setting. Basically it gets warm and thats about it, its just warm enough to where im fine. I do notice if im not driving and just idling it wont blow warm anymore. My heat gauge is either always right below or right on the 210 degree mark. The car has 73k miles. Right now it is throwing a p0400 EGR code (exhaust gas recirculation malfunction), but the car runs flawlessly power wise idling wise not stumbling whatsoever. I dont think the p0400 code has anything to do with it. When i turn off the fans it sound like something is "de-pressurizing", or hissing. I'm not sure how the heating system in this car works or what a common problem might be.

Also when the car is idling and i had the hood up with the heat on high on re-circulate it was making a loud "hissing" sound towards the back of the engine. Maybe it was jsut sucking in fresh air idk.

nemss1

no, the code has nothing to do with it. i know this may sound stupid, but is your coolant topped off? if your car is low on coolant, the heater will not work as well. heat comes from the heater core which hot coolant runs thru

eseibel67

iTrader: (10)

There is a vacuum line running from the intake to the heat control behind the computer.

If it's broken, your heat settings will be stuck in one position, and it will make a hissing noise.

nomoneyz

iTrader: (15)

Don't know about your hissing noise but my Camaro had terrible heat. I unhooked the heater hoses at the water pump and flushed the heater core out with high pressure water and put it back together and bled the cooling system to get all the air out. My heater now kicks major. I end up turning it off cause I get too warm.

06 SS

if the hose is broken (brittle plastic) that eseibel67 was talking about, your heat would only blow into the footwells. In order, I would look at coolant level, bleeding the system out, then a clogged heater core. Nothing else that I can think of would hamper the heating system (assuming your t-stat is good, which it sounds like from you description)

SOMbitch

iTrader: (8)

Sounds like the classic stopped up heater core...

fire-chickens

Also for some reason i would have reason to also think my car may have a 160 degree thermostat, jsut because my heat gauge is never above the 210 mark and mostly a touch below it at all times. I think im going to flush the heater core and then if that doesnt work i think im jstu going to guess that i have a 160 degree thermostat. there were some small things that lead me to believe that this car has small minor mods done to it.

So far my skip shift light has come on dozens of times but never made me go to 4th gear, so i know its got the eliminator, i think the first owner did a tune-up on it because its already got aftermarket plug wires. i got the receipt for the intake which amusinly was installed by a speed shop back in 2007 believe it or not. the car has sequential tailights. i know the owner i boguht it off of did not do any of these things, he never mentioned the tail lights to me or the plug wires ever being done or anything of that nature. and he had only put 13k miles on it since 2007...

and all this is on a 73k mile car so it wasnt ever due for a tune up that soon

Grizzlyrider700

i am having the same problem on my 95 trans am, my fluid lvl is good and i just put a new 185 stat in and having the same problem and i am fixing top flush my heater core.