00' Silverado no heat


bsilverado00
02-11-2008, 03:09 PM
This issue started a few weeks ago, let the truck sit for a couple of days and no heat, did a radiator flush, replaced the thermostat/water outlet. Hose into heater core hot, return hose cold. Is there anything else in that cooling loop that could cause the problem, or is the core plugged? It's an ext cab 5.3. All help appreciated.

inafogg
02-11-2008, 03:20 PM
hello if hose is cold = clogg. you can try removing heater hoses & flush out heater core.(back flush first) if this does'nt help you may need to replace.
GOOD LUCK!!

j cAT
02-11-2008, 03:23 PM
This issue started a few weeks ago, let the truck sit for a couple of days and no heat, did a radiator flush, replaced the thermostat/water outlet. Hose into heater core hot, return hose cold. Is there anything else in that cooling loop that could cause the problem, or is the core plugged? It's an ext cab 5.3. All help appreciated.
the heater core appears to be blocked.
i have 2000 5.3 dexcool coolant . when i replace coolant i have found debris only in the heater core. coolant is very clean after 5years which is my r/r cycle. so if you disconnect heater core hoses at engine thermostat and force water into heater core and reverse this should show if this was the problem. also when filling coolant keep fill cap off. run engine to operating temp could be air in system....

bsilverado00
02-11-2008, 04:22 PM
I'm thinking air in the system as j cAT said. I removed cap, let run until operating temp, had heat, both hoses hot, coolant level didn't change. I'll see in the morning once it cools down, if that solved the problem

bsilverado00
02-14-2008, 02:42 PM
Let's see, I back flushed the heater core, it's not plugged, ran it w/o cap until operating temp, as said earlier replaced thermostat, flush and fill coolant, sporadic heat, all doors on heater box functioning properly, what should I check next??????????

j cAT
02-14-2008, 04:16 PM
Let's see, I back flushed the heater core, it's not plugged, ran it w/o cap until operating temp, as said earlier replaced thermostat, flush and fill coolant, sporadic heat, all doors on heater box functioning properly, what should I check next??????????

have you had to add coolant ? i can go 2-3yrs before i add a couple of oz. if you have leak this is the only reason i can come up with. does heat return when cap is removed if so this once again could be leak or worse a head gasket and some exhaust gases getting into coolant... i hope not !

littlebitnorth
02-19-2008, 04:10 AM
Heres a curve ball for you. I have a 2001 and twice the heater has quit blowing warm air. I shut down and restarted and everything worked. Both times it was damn cold(40 below). My point is with mine it was a switch/computer issue that some how resolved itself by powering down. Just something to consider.

j cAT
02-19-2008, 11:01 AM
Heres a curve ball for you. I have a 2001 and twice the heater has quit blowing warm air. I shut down and restarted and everything worked. Both times it was damn cold(40 below). My point is with mine it was a switch/computer issue that some how resolved itself by powering down. Just something to consider.

your problem i believe is the temperature control unit this is mounted on the under dash air ducting directly above the floor hump this a common failure along with the damper door that is controlled by this componet sticking .his problem was one hose hot the other cold going to heater core... these should always be hot...temp control unit does not restrict coolant flow it only directs air flow.........

deoncollins69
02-21-2008, 08:24 PM
This make take some time but make sure the return line is not colapsing. Hose have good expansion qualities but no quality to hold vacum. Just a thought. I had an upper hose cause a cooling issue this may cause a heating issue int he core. If you do not have a colapsed hoe try finding the cabin filter cover if you have one. Pull the door and you should be able to see the core. One way or another check the surface temp. if it is hot it's fine. One other thing Do you have digital climate control? If you do it is a sensor.

gmvortec
02-22-2008, 08:54 PM
This issue started a few weeks ago, let the truck sit for a couple of days and no heat, did a radiator flush, replaced the thermostat/water outlet. Hose into heater core hot, return hose cold. Is there anything else in that cooling loop that could cause the problem, or is the core plugged? It's an ext cab 5.3. All help appreciated.


Is your water pump pumping properly, had to replace one last week, no heat same as you, not leaking or noisy it just wasn't pumping enough water round the system, impellor was corroded.

bsilverado00
02-23-2008, 06:52 AM
What I found was an air pocket in the heater core, loosened the return hose burped the air, and I've had heat for a week.

j cAT
02-23-2008, 02:11 PM
What I found was an air pocket in the heater core, loosened the return hose burped the air, and I've had heat for a week.

hopefully that air bubble won't come back!!!!!

ducati1
02-05-2009, 07:01 PM
I have a similar issue with Mine but it has a twist. I have little heat, fan speed 1 or 2 produces heat but anything more does not. Blew out the heater core last fall just in case and it was PERFECTLY CLEAN. I changed the thermostat a couple weeks ago and it was a little bit better. Everything was VERY clean inside the water pump and fuild was clean as well. The engine temp seems to be operating just fine. I have notice that if I am on the highway at over 2k rpm I have significantly MORE heat... I think the water pump is corroded. Has anyone seen this issue?

ducati1
02-05-2009, 07:02 PM
One more note. The hose is hot one side and cold the other but I could not find a clog anywhere...

FrankB43015
02-05-2009, 08:06 PM
Make sure you flush in both directions. I flushed into upper hose and out lower hose and saw nothing, switched directions and the flow was much slower, then the clog came flying out. Instant heat! Acts like a new truck again - not bad for 176,000 miles.:grinyes:

ducati1
02-05-2009, 10:38 PM
are you flushing the hose or the heater core? I flushed only the heater core... I flushed the direction the fluid goes and it seemed to flow completely free using a garden hose.
I thought maybe an air lock but the RPM makes me think the water pump is not pushing enough...

chevy393
02-06-2009, 01:46 PM
i have the exact same probelm as ducati, i have like luke warm to nothin coming out and if i put it on 4 or 5 its pointless cause it blows it so hard it turns into cold air lol. i was goin ot take it to a mechanic friend and see if he could dignose it or somthin, ill let yall know if i find anything intersting out

johnny-Z
02-06-2009, 04:11 PM
That's funny becuase my heat will not turn off in the winter time even if I turn it off or turn on the A/C. Once it's on it won't go off unless I turn the car off and let it sit for hours with the temp on cold and A/C on.

However air continues to blow even when it is turned off. Is there a vent somewhere that I need to close?

How can I get the heat to turn off once I turn it on?

ducati1
02-06-2009, 09:55 PM
I think I will try the reverse heater core blow out but I think my water pump is shot... both hoses should be hot all the time if I understand the design properly. If you are getting cold all the time it could be the trap door not moving, which I can hear mine move when I switch from cold to hot...

j cAT
02-07-2009, 01:28 PM
I think I will try the reverse heater core blow out but I think my water pump is shot... both hoses should be hot all the time if I understand the design properly. If you are getting cold all the time it could be the trap door not moving, which I can hear mine move when I switch from cold to hot...

to have only one hose hot at the heater core means that coolant is not flowing thru the heater core...reverse and fwd flush out the core there should be no resistance to the flow...there are no valves...so it this is open and free flowing the most likely cause is the air bubble.....when reinstalling hoses I disconnect at the engine then when reinstalling fill heater core as best I can,,,,,,, then hook up hoses to engine...then run engine with the fill cap off and keep filling the res....rev engine to 2-3,ooorpm a few times to get the flow/air moving to the res ..do this until engine is hot...





IF THE HOSES ARE BOTH HOT AND NO HEAT THE CONTROL MOTOR IS BAD this is in the air box next to the center hump..

slvbeard
08-07-2009, 07:33 AM
I have a problem where the temperature gauge goes up above normal, and the heat gets cold. After about a minute the temperature gauge goes back to normal and the heat gets warm. I replaced the thermostat and it seemed to work fine for about a month, but now it's doing it again.

j cAT
08-07-2009, 12:33 PM
I have a problem where the temperature gauge goes up above normal, and the heat gets cold. After about a minute the temperature gauge goes back to normal and the heat gets warm. I replaced the thermostat and it seemed to work fine for about a month, but now it's doing it again.

flush out the heater core..remove hoses at engine
flush the core out with a water hose into a bucket,,,if its black goop your gonna have to somehow cleanout all of the coolant system ..

dexcool and distilled water only....mixing of other coolants will goop up your system...

slvbeard
08-08-2009, 12:15 AM
flush out the heater core..remove hoses at engine
flush the core out with a water hose into a bucket,,,if its black goop your gonna have to somehow cleanout all of the coolant system ..

dexcool and distilled water only....mixing of other coolants will goop up your system...

Checked the hoses to the heater core and one was hot and the other cold. Pulled the hoses off the water pump and flushed them and the heater core out, working great now.

j cAT
08-09-2009, 08:45 AM
Checked the hoses to the heater core and one was hot and the other cold. Pulled the hoses off the water pump and flushed them and the heater core out, working great now.

next time the coolant is replaced,,,always flush out the heater core,,,then blow out the flush water,,,this will ensure you have heat come winter...where I live it is very important this heater core works...

myk55
01-11-2016, 04:26 AM
when the outside air temp is 20 degrees or higher I have heat in my 2000 chevy Silverado 1500. when its colder outside it blows cold air? and when I turn heat on I can smell antifreeze ( not all the time)? replaced thermostat and all my hoses seem to be heating up and my fluid level is good?

rhandwor
01-11-2016, 05:23 AM
Put some cardboard under the air conditioning drip tube if it's stained your heater core is leaking. The stain should be the color of your antifreeze. Check the vacuum going to your blend doors. The control on the right has a lot of vacuum tubes make sure you have vacuum and it switches.

myk55
01-17-2016, 05:38 AM
would bad knocking sensors cause my 2000 chevy slverado 1500 5.3l v8, To kind of lunge? when stopped? the rpm gauge fluctuates up and down and truck kind of lunges forward a little bit. And when its running it sounds like there is a delay? (like its going to quit running)? Not sure if I'm explaining the problem correctly?

j cAT
01-17-2016, 09:07 AM
would bad knocking sensors cause my 2000 chevy slverado 1500 5.3l v8, To kind of lunge? when stopped? the rpm gauge fluctuates up and down and truck kind of lunges forward a little bit. And when its running it sounds like there is a delay? (like its going to quit running)? Not sure if I'm explaining the problem correctly?

when you have issues you must not use another form members post issue. start your own new posting with the details of your vehicle spec's and what you have tested/inspected with what you have found.

you will get better / more results .

with no codes check the fuel pressure .. this requires a pressure gauge 53-62 psi.. squirts real good is not a test...AS SOME HAVE DONE. LOL...

gtbreps_2
01-18-2016, 12:00 PM
I had an issue similar this summer. To the contrary, the temp control would work for a little while until it would change to max. heat and I could not make it colder, until I turned my truck off. It was the blend door actuator located under the center dash console. It was an easy fix. If that has gone bad, it won't move the blend door to control the temp.

j cAT
01-18-2016, 01:19 PM
I had an issue similar this summer. To the contrary, the temp control would work for a little while until it would change to max. heat and I could not make it colder, until I turned my truck off. It was the blend door actuator located under the center dash console. It was an easy fix. If that has gone bad, it won't move the blend door to control the temp.

if you have a heat problem @ 20 deg f or lower , this would be a dirty heater core or a bad T stat not closing enough to keep the engine temp @190 deg f. having a leak would effect the flow thru the heater core but that would effect the heat temp at all temps.

I put a thermometer in the vent and it does go up to 140 DEG F with the fan on the middle speed at all temps.. the heater core is like a filter debris collects there.

Blue Bowtie
01-20-2016, 07:20 AM
...The control on the right has a lot of vacuum tubes make sure you have vacuum and it switches.

I would have thought that by 2000 they would have at least changed the control to transistors, if not monolithic or thick film devices. I thought only the Russians and Hungarians were still using vacuum tubes.

As for the hunting idle RPM, surging and stalling, it could be time to clean the throttle body, idle air control passages, and remove the idle air control to disassemble, clean, and lubricate it. I JUST went through this on an '05 with the same kind of symptoms, and that's all I did to rectify it. It hasn't been quite as cool here as in Eau Claire, but as soon as it hit about -10F the symptoms began. There was just enough varnish buildup on the IAC stem to make it sluggish to the point where the PCM was trying to "chase" the idle RPM with air adjustment but the IAC couldn't react quickly enough. It would hunt from OVER 2,000 RPM to stalling, even in neutral. Once the IAC was cleaned/lubed/reinstalled it immediately went back to normal (No, not Normal, Illinois, only Rockford).

This may be of some help: http://www.automotiveforums.com/vbulletin/showpost.php?p=7177067&postcount=7

dakota1205
01-20-2016, 08:47 AM
I'v had the same issues on my 00 silverado z71. I back flushed my heater core and gunk come out of it. I'v had to do it once a year about this time. I still use the dexcool and just use regular tap water. Could regular tap water make the dexcool gunk up over time? Once I backflush, it works great though.

j cAT
01-20-2016, 08:55 AM
I'v had the same issues on my 00 silverado z71. I back flushed my heater core and gunk come out of it. I'v had to do it once a year about this time. I still use the dexcool and just use regular tap water. Could regular tap water make the dexcool gunk up over time? Once I backflush, it works great though.

the Dexcool issues are most times from using dirty contaminated water.. tap water has chemicals that react to Dexcool in a bad way. I have used Dexcool for now over 20 yrs. still have a 96 impala and funny how when the car was new I had heater problems but not now since I use distilled water with 60%dexcool.. 2000 silverado same thing 16yrs now and the coolant system still working great good heater heat about 130 DEG F out the vents. 20deg F air temp... flushing is done at each coolant change and I also blow it out ..

dakota1205
01-20-2016, 09:10 AM
ok.
Thanks for that info. Sounds like I need to do a flush & blow and replace with Distilled water next time. If you've had that good luck, then I need to try it. Should the same water be used with the "Green" antifreeze as well??

j cAT
01-20-2016, 05:08 PM
ok.
Thanks for that info. Sounds like I need to do a flush & blow and replace with Distilled water next time. If you've had that good luck, then I need to try it. Should the same water be used with the "Green" antifreeze as well??

well back in the 1980'S I began the distilled water and block drain because of the radiator have scale build up on the cooling tubes before Dexcool existed . thats when I stopped using dirty drinking water that scale and corrosion ended. I used the prestone green back then as all had this coolant. the 2000 and 1996 comes with dexcool so when these are changed to a non dexcool / so called compatibles antifreeze this does create problems with black goop being grown .. remember GM approved Dexcool is what to use compatible is not dexcool.

so in 1996 I continued with the distilled in my new 96 impala and then in 2000 the silverado no coolant problems distilled water does work.. drinking water has too many metals and corrosive bacterial killers .. the dexcool is replaced every 4 yrs .

777stickman
01-20-2016, 09:35 PM
I've been mixing my own distilled water 50/50 mix for more years than I can remember.

There is a graph on each antifreeze bottle that shows what the % mixture should be for the temps expected.

You can buy a 50/50 pre-mix at most parts stores, but I'm not sure what kind of water they use for the mix??

Bottom line is always use distilled water and do not mix colors!!

j cAT
01-21-2016, 07:10 AM
I've been mixing my own distilled water 50/50 mix for more years than I can remember.

There is a graph on each antifreeze bottle that shows what the % mixture should be for the temps expected.

You can buy a 50/50 pre-mix at most parts stores, but I'm not sure what kind of water they use for the mix??

Bottom line is always use distilled water and do not mix colors!!

I look at it this way $5 for a 1/2 gallon of water not good ! distilled $1 a gallon about $12 a gallon for 100% anti freeze..much cheaper . pure antifreeze has longer shelf life..

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