Heat works one day not another

sdimew7 · 01-29-2007, 03:13 PM

well, my heat works some days and others its doesnt. the days it doesnt the air is like room temp. I drive a 00' Chevy blazer 4wd, with 80k. I figured it was my thermostat. but i went and bought one then did a search on here how to replace it and found out that if the hoses are warm there not clogged and the thermostat isnt frozen. i also was low on coolant which when the problem had happend, i had put more in and about a half hour later it was fine. next day gone again. But i was just giving my buddy a ride home after we did this search and the heat worked on the ride over and back. so im pretty clueless right now.

any suggestions?

menotyou · 01-30-2007, 03:19 PM

I have had similar problems on cars with low coolant, a little air gets trapped behind the thermostat and prevents it form opening up.

What does your temp gauge read when the heat fails? If it is running on the cool side then the thermostat might be sticking open, giving you a warm hose but not allowing the engine to heat up.

Also, slight possibility that the heater core could be on the verge of plugging. Some debris could be coming loose allowing the coolant to circulate and then clogging again later. It's a long shot but should not be entirely ruled out.

97ChevyBlzrCosp · 01-31-2007, 03:40 PM

I've had problems with myine and my girlfriends blazer doing the same thing... you should start your truck up and let it run checking your temp...the first time this happened it was on my truck and everyone and there grandpa had a solution well about 500 dollars late ri had to have my intake gaskets replaced and my mom did it while i was away , she took it to a mechanic and it cost about 1200 dollars which is not fun, when you look for fluid look behind and under neath the fan if fluid is coming from there you could need a new waterpump, you could replace your temp sensor which is in close proximity to the thermostat. My girlfriends was an easy fix, the person that owned it before her wanted to have there radiator acid dipped but they changer the new blazers from all aluminum radiators to haveing plastic on the sides so when they did the acid dip on the radiator they siliconed the platic part of the radiator back on which was leaking causeing an overheating problem. i got a new radiotar for about 200 bucks from a guy i know and havent had a problem since, you can do a intake gasket replacement by yourself if you have the know how to remove everything and the time on your hands the little things will cost 10 to 20 bucks each so good luck if you still have problems email me at Ostrich_Man@msn.com and I'll rack my brain for some more ideas

sdimew7 · 02-04-2007, 12:41 AM

well i havent had a problem with it not working at all now. now its just not hot. i thkni its th thermostat sticking. because it stopped being completely cold after a decently warm day for being febuary in new york. anyone else thats living around here knows how cold its been these last couple weeks. but yeah ill check behind the fan for any leaking.

thanks guys appresiate it a lot

aircrewman · 02-07-2007, 10:40 PM

Back flush your heater core, dexcool sometimes after 80k or so gels up. I back flushed mine and some nasty scab like chunks came out, so I bought a flush kit, and it seemed to help a bit, my thermostate needs to be replaced and I think it will work as advertised.....

01-29-2007, 03:13 PM	#1
sdimew7 Registered User Age: 22 Join Date: Jan 2007 Posts: 2 Location: User is: OffLine	Heat works one day not another well, my heat works some days and others its doesnt. the days it doesnt the air is like room temp. I drive a 00' Chevy blazer 4wd, with 80k. I figured it was my thermostat. but i went and bought one then did a search on here how to replace it and found out that if the hoses are warm there not clogged and the thermostat isnt frozen. i also was low on coolant which when the problem had happend, i had put more in and about a half hour later it was fine. next day gone again. But i was just giving my buddy a ride home after we did this search and the heat worked on the ride over and back. so im pretty clueless right now. any suggestions?
	[Reply w/Quote]

01-30-2007, 03:19 PM	#2
menotyou Registered User Age: 29 Join Date: Jan 2007 Posts: 42 Location: User is: OffLine	Re: Heat works one day not another I have had similar problems on cars with low coolant, a little air gets trapped behind the thermostat and prevents it form opening up. What does your temp gauge read when the heat fails? If it is running on the cool side then the thermostat might be sticking open, giving you a warm hose but not allowing the engine to heat up. Also, slight possibility that the heater core could be on the verge of plugging. Some debris could be coming loose allowing the coolant to circulate and then clogging again later. It's a long shot but should not be entirely ruled out.
	[Reply w/Quote]

01-31-2007, 03:40 PM	#3
97ChevyBlzrCosp Registered User Age: 21 Join Date: Jan 2007 Posts: 1 Location: User is: OffLine	Re: Heat works one day not another I've had problems with myine and my girlfriends blazer doing the same thing... you should start your truck up and let it run checking your temp...the first time this happened it was on my truck and everyone and there grandpa had a solution well about 500 dollars late ri had to have my intake gaskets replaced and my mom did it while i was away , she took it to a mechanic and it cost about 1200 dollars which is not fun, when you look for fluid look behind and under neath the fan if fluid is coming from there you could need a new waterpump, you could replace your temp sensor which is in close proximity to the thermostat. My girlfriends was an easy fix, the person that owned it before her wanted to have there radiator acid dipped but they changer the new blazers from all aluminum radiators to haveing plastic on the sides so when they did the acid dip on the radiator they siliconed the platic part of the radiator back on which was leaking causeing an overheating problem. i got a new radiotar for about 200 bucks from a guy i know and havent had a problem since, you can do a intake gasket replacement by yourself if you have the know how to remove everything and the time on your hands the little things will cost 10 to 20 bucks each so good luck if you still have problems email me at Ostrich_Man@msn.com and I'll rack my brain for some more ideas
	[Reply w/Quote]

02-04-2007, 12:41 AM	#4
sdimew7 Registered User Age: 22 Join Date: Jan 2007 Posts: 2 Location: User is: OffLine	Re: Heat works one day not another well i havent had a problem with it not working at all now. now its just not hot. i thkni its th thermostat sticking. because it stopped being completely cold after a decently warm day for being febuary in new york. anyone else thats living around here knows how cold its been these last couple weeks. but yeah ill check behind the fan for any leaking. thanks guys appresiate it a lot
	[Reply w/Quote]

02-07-2007, 10:40 PM	#5
aircrewman AM1 (AW/NAC) P-3's Age: 32 Join Date: Jan 2005 Posts: 514 Location: Orange park, FL User is: OffLine	Re: Heat works one day not another Back flush your heater core, dexcool sometimes after 80k or so gels up. I back flushed mine and some nasty scab like chunks came out, so I bought a flush kit, and it seemed to help a bit, my thermostate needs to be replaced and I think it will work as advertised.....
	[Reply w/Quote]