Luke Warmwater (71.87.45.231) - Sun Sep 14 11:29:36 2008

97 S10 Blazer no heat

I get barely any heat out of my blazer, the engine temp and thermostat are ok.

There appears to be no circulation through the heater core - only one hose is warm.

The temp selector potentiometer seems to work...is there a a/c control valve in the heater core water line?

Thanks!

Reply #1 Ernest C Jackson (74.177.51.245) - Tue Oct 7 15:55:21 2008

1999 Chevy S10 Blazer heater wan;t heat. I back flushed it no heat, I flushed the entire cooling system no heat. The front of the engine was verry greasy looking I thought the front main seal was leaking. I cleaned it with a pressure washer. the seal wasn;t leaking.

I changed The water pump the weephole was leaking the oily substance was pink antifreeze.

I now have heat like A new car .The water pump must have been strong enough to cool the engine but not srrong enough to fill the heater hoses so check the water pump it might be your problem to.

Reply #2 dustin (24.131.109.226) - Wed Oct 8 16:44:53 2008

did you ever think to change your heater core?

Reply #3 craig miller (98.243.123.75) - Tue Nov 18 16:23:28 2008

undo heater hose from engine. supply and return put one end in a container and blow the other end with a air hose. i did it with my blazer , my sons blazer, and my sons girlfriends blazer. worked each time. good luck

Reply #4 Wally (24.164.170.183) - Fri Nov 21 12:23:18 2008

Craig - can you explain you fix a little more? Do you remove both hoses (inlet & outlet)? And, do you remove them completely, and blow air thru them?

Or do you mean remove one end and blow air thru them - and thru the heater core?

Thanx - Wally

Reply #5 michelle (99.177.172.21) - Tue Dec 2 17:42:31 2008

just had this same problem. I just want to save everyone the headache and money. all i did was pull the a/c fuses from under the hood.my heat works just fine.

Reply #6 chris layer (24.213.101.229) - Thu Jan 1 16:33:56 2009

I had a low temp thermostat. heater only blew luke warm air.

found a vacume line crimped. fixed this vacumm line and that helped a bit. I decieded to goto the local auto Zone and get a 190 F degree thermostat. Before My temp hand only read 140 now it is close to 185 195.

Reply #7 Jim Peterson (71.34.61.108) - Thu Jan 1 22:45:54 2009

My Son’s 1997 Blazer heater that doesn’t heat....After running the engine for some time the hose from the intake manifold is very hot, while the one that connects to the water pump is cool. Since this suggested a clogged heater core and/or hose, I removed the hose that connects to the water pump and started the engine – no flow! The hoses seem to be just fine/no kinks.

I thought the hose from the water pump was the supply, the one from the manifold was the return but that can't be the case.

Would flushing the heater core using water/bubble method be a good idea, i.e., 1) remove both hoses and place one in bucket 2) connect garden hose and air line to the other hose 3) carefully apply water and air 4)alternate directions until water is clear/flows freely?

Thanks!

Reply #8 rick (216.68.236.9) - Tue Jan 27 17:12:47 2009

i've changed my thermostat to a 190 the engine temp is still 160 the stat is working the engine temp gauge will rise to 210 and then go to 160. there is very little air coming out of the vents. but the blower is running fine.

Reply #9 David O. (173.55.68.195) - Fri Feb 20 00:43:45 2009

I've been bothered by a radiator fluid smell in the cab of my truck when I turn on the heater or even when I switch the temp from cold to hot on the dial (w/out turning in the air).

Also, I read that you guys think its a clogged or dirty heater core, but in my instance I hear the radiator fluid flowing thru the heater core as I step on the gas; the hard I jump on the gas, the faster and louder the flow!

I do get some heat, it starts off low and after 30mins or so the air heats up to a comfortable temp, but at the same time I get the radiator fluid smell... boy does that smell awful when it's cold out and you have the windows up to stay warm!

Anything will help...

Thanks in advance,

~David O.

Reply #10 shawn (65.161.188.11) - Tue Feb 24 05:22:54 2009

The antifreeze smell means that your heater core is going bad and may soon leak if it does the fluid will be on the floor inside the vehicle. Make sure to get it replaced as soon as possible

Reply #11 jeff (74.64.93.133) - Sat Mar 28 20:30:34 2009

i have a 2000 blazer no heat i had changed water pump radtior and theromste its all cloged up with browmn muddy stuff i can blew threw heater core so i dont think its cloged no water is cirle it over heats and i always have no fluid can see no leaks

Reply #12 ron (71.17.27.145) - Thu May 7 23:40:11 2009

I have a 1999 s10 if i turn knob so the air comes out from dash,

my heat control is on hot and my control knob is on any speed

I turn my heat control to the cold position and my air flow

doubles out of the vent.When i have the speed control on 4 there

is air flow but it sounds restricted.

Reply #13 Dennie (71.71.244.98) - Sun Aug 16 20:22:56 2009

location of 94 S10 Blazer

Reply #14 Dennie (71.71.244.98) - Sun Aug 16 20:29:47 2009

94 S10 blazer heater core location

Reply #15 tony (76.237.200.219) - Tue Oct 13 20:47:15 2009

i have a 2001 chevy blazer i changed my thermostat and temperature is moderate but the hoses to my heater core are cold any answers?

Reply #16 Melissa (24.16.11.47) - Wed Oct 14 21:11:07 2009

Hi I have a 2000 Chevy Blazer, Changed the water pump, and the temp control, and now all I have is luke warm heat coming from the vents. I am not sure where to look next or what I should do. I also have changed the themostat. Winters here and I need heat! If any ideas please send my way, like to be able to fix this myself... thanks

Reply #17 Brian Leddon (199.168.7.243) - Fri Oct 16 02:27:36 2009

On some models there is an electronic heater control valve on the manifold near the thermostat that controls the flow of engine coolant to the heater core. Unplug it, if you get heat after that - the controller or valve is bad. If that doesn't work pull the valve and check its condition. I always pull a heater hose going to the heater core and blow through it to make sure it is clear before I do anything with the control valve.

Reply #18 Mike (4.225.23.80) - Fri Oct 23 14:16:28 2009

I have a 1997 Blazer with no heat here is a list of my attempts to fix the problem. Replaced thermostat, flush and refill, flushed heater core and back flushed heater core, replaced heater core"this was a real treat as I had to drop the steering wheel and remove the entire dash from the vehicle not for anyone unsure in their mechanical skills"!!!no helpat all in getting me any heat." Yesterday in a last ditch effort I had the radiator serviced and reflushed the new heater core flushed the engine block and overfill tank all hoses were checked I refilled with Dex Cool and sitting in the driveway it started to feel like I may have finally beat my problem because it did start to blow a little heat. I drove it down the road about 10 miles and the heat really started to pick up. Then all of a sudden it went rigt back to blowing cold air. anyone with any other ideas thanks Mike

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