Have checked heater core by taking air hose and blowing thru to other side no leaks does not overheat no lights come on just no heatany help would be appreciated BRRRRR
Your '99 Blazer does not have a water valve. Just a temp. blend door. In other words, hot water should be flowing through the core at all times. Like the other techs said, make sure you are getting the whole system full of coolant. You might even try disconnecting one hose, and pouring water into the heater core itself. On most of these year models, if you listen, you can hear the rush of water through the core when you lightly rev the eng. I have replaced 3 heater cores just last year on '96-'99 Blazers. They clog easily. YOu can blow or flow water through them, but if they don't flow freely, I mean without any restriction whatsoever, they will not get as hot as you want. The thing is tiny!
Here's an easy test: Run engine until temp gauge reaches normal: around 180-200 degrees. Reach back to the firewall and grab both heater core hoses. Are they both about the same temp. and HOT? THey should be. If one is much warmer than the other. You are clogged enough to suffer in the winter. And from what you said: "Brrrrrr" You are getting poor performance out of your heater.
BE sure to check that the blend door is working. Is it cool when you set temp to cool? Blazers go through way more heater cores than they do blend doors, so I'm betting your core is either empty, or clogged. TaterTodd
Could be the thermostat, or the blend door actuator. If it's not low anti-freeze. It does blow air, correct? If not, check the heater fuse or the blower resistor. Take care and best wishes to ya.
Make sure you are full of antifreeze to the top of the radiator .. also your water valve is working properly isnt it ? sometimes they are outside firewall and are vacuum operated. lets water go inside the core.
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My heater has been blocked and I flushed. Recently had head gasket repaired. I replaced radiator and battery now the car won't start . What am I missing?
i blame the good old dexcool for cloging the heater core and eating up intake and head gaskets i take it out and i use the green but if your heater core is pluged and back flushing does not fix it then this is a fix seeing as how you need to replace the heater core any how because it is pluged you have nothing to loose if you put a hole in it. with this fix i have done 4 of them with no problem remove the 2 heater hoses from the engine blow out the watter now use battery acid (avable at auto parts stores) pour it into the heater till it is full let it set for 2-3 minites and blow it out with compressed air do it again a 2nd time but this time revures the flow then flush it out with lots of water use rubber gloves and goggles be carefull not to get on the car if you shound get some on the car or your self flush with lotts of water i have also used meraitc acid but it is way to powerful but it did the job with no problems
no hot air coming from heater replaced thermostat and heater contrils
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