I have seen a few threads but only pertaining to the LT1 engines not the LS engines, but I have no heat and the other posts said to flush the heater core out with a garden hose, not too much pressure, so I need to know is it the 2 hoses off to the side of the water pump that I need to pull off and flush out or do I need to pull the glove box and dash apart and pull the heater core out completely and flush it out (and if I go that far I might as well replace the stupid thing if its that involved)
Or what have others done that lost their heat to restore it?
Thanks in advance

J

 

The heater does run off the 2 hoses off the water pump, so if you wasn't to flush the core you could do it that way. One other thing to check for is if all the air is out of the core.

 

Sounds like you either have trapped air or your coolant level is too low. Does it get warm if you rev the car up? You could also have a bad thermostat, but if that were the case, you would still be getting some heat.

 

I replaced the thermostat about 3 months ago when I put a whole new Radiator in the car. Along with new upper and lower hoses etc. So I did replace it with the lower temp thermostat like 165 or something degree, I might have to get the normal 180 or 185-190 degree thermostat to let the car get warmer than this thermostat is allowing but still I have absolutely NO heat, not even Luke warm heat.
So if I pull those 2 hoses off the side of the water pump and flush them with a garden hose like the LT1 form posts said to do and see if there is any crud in there blocking it, that should hopefully resolve my issue? Air trapped in the lines? Would after a few months the lines be burped enough to allow coolant to flow to the heater core?
Thanks All!!!

J

 

Not very often do heater cores completely plug up. Is your temp gauge coming up to normal? Are the two heater hoses getting warm? What kind of vehicle? Maybe the valve to turn the heat on is not working or maybe you've got a blend door that's not opening properly.

 

I seem to recall there being a problem with some combinations of thermostats & WPs, wherein the thermostat bottoms in the WP and gets held open, which of course pretty much voids the heater and also makes the whole thing run too cool... can't remember the details (as they say, when you start to get old, the 2nd thing you lose is your memory, but I forgot what the 1st was supposed to be)… any possibility this is the case here?

 

Suggestion...…..until you figure out what's up, set your HVAC to the "Vent" setting.

This should at least allow you to draw heat into the car.

KW

 

This was what I had done to get a guys heater working to get him through the winter. I removed the lines from the water pump and filled the entire system with CLR and let it soak in good. Then with one line in a bucket and the other line outfitted with an air fitting I blew compressed air through the system removing a bunch of rust from the heater core. I asked him what he used for engine coolant and he said all I've ever used was water. I asked what kind of water and he said just water. Anyhow it worked to get him through the winter but ultimately we ended up doing a bypass a few months later because removing one is PITA!

 

Did the no heat problem start when all of that was replaced? New thermostat could be bad, I have seen many of those. Like others have said, what does your temp gauge say, and do the heater hoses feel hot? Vacuum line left off to dashpot controls (not sure if your car uses vacuum to change blend door positions).

 

Car uses a cable to open/close the blending door behind the dash on the firewall.... Not sure any cars use vacuum these days to operate the blend doors.
i have not felt the hoses yet, have not really gone anywhere last few days, so Ill get out and look as soon as all this rain goes away
As far as the ? about the temp the car has a new 165 degree thermostat/housing i put in like 3-4 months ago and the car does get warm but not very. The new monster all aluminum radiator I installed as well does an AMAZING job at keeping the car stupid cold even on 100 plus degree days along with the 165 degree thermostat she runs very cold. When on the highway in 6th the needle will be basically not moved at all, in traffic sitting on the highway stopped or 2-3 miles an hour stop and go stuck for an hour it might move up 1/8th to 1/4 of an inch, so its not even 170 degrees, between the monster dual core all aluminum radiator and the thermostat it really just does not register much heat at all the needle moves very VERY little. Not even to the first mark. So the bottom mark all the way to the left is the 160 degree mark, the 2nd mark is 185, center is 210 and next is 235 then all the way max is 260 degrees.
This car with the radiator and thermostat stays around 160 to 175 ish. Not ever reached the 185 mark that I have seen. Now that I think about it, I think it would run better if it ran around 185 190 to have a more complete combustion burn and overall performance, Am I taking too much heat out of the system and not getting it warm enough to run properly?

thanks all

J

 

You should still have heat unless the thermostat is stuck open or something else faulty. What do the heater hoses feel like after driving? Each of them. Even a car with a cooler t-stat makes heat at the vents when all is proper.

 

Jenn, I think I’d try a 180* tstat. Sounds like the engine isn’t building enough heat to help you stay warm. If there was a way you could put card board over like 1/2...3/4 of the radiator front, and drive it around the neighborhood (if it starts to get too hot, kill it and remove card board) to see if it would build a little more heat, it would be a great way to see if you have other problems, such as a heater core issue.
Ive seen cars have the tsat stick open, and it not be a problem in the summer, but come fall when outside temps drop, car won’t make any heat and heater not work, just like what your going through.

 

AHHHH WHOA thats an AWESOME idea. Its pouring out now so Ill have to wait for the car and the roads to dry up hopefully tomorrow, but I can shove some cardboard up there and zip tie or tape it in place with duct tape and just leave the side or center part open, I replaced the radiator with this monster like Truck sized radiator or one similar to my big block corvette radiators now in retrospect maybe putting such a massive radiator in a car with an all aluminum engine and a super low 160 = 165 degree thermostat was not the worlds best decision but whats done is done, I just need to fix it so this is a phenomenal idea. I will report back once the rain stops and I can get this test done to see if in fact I generate a lot more heat and it flows to the heater core or if its blocked then no matter what I do with the thermostat and radiator, a new heater core will be required if its completely clogged and plugged up and not able to get the crap out of it.
Thanks, ill let you know hopefully tomorrow or Friday.

Jenni

 

Also with a wide open thermostat you should get some heat eventually, if the car is running around 160 or 165 degrees, that temp water is flowing through the heater core, so you should get at least SOME heat out of it, I have the air blowing cold like whatever temp the air inside the car is, just blows out. So if the sun warmed up the inside of the car on a 45-50 degree day but its about 75 or 85 in the car then I get that coming out, if its night time and its like 42 degrees out, I get 42 degree air circulating so its completely inop!!!! But this card board trick should definitely let me know what the deal is. VERY smart idea and FREE and easy way to determine whats what.

Troubleshooting 101
Check the OBVIOUS and EASIEST things FIRST! 99% of the time thats what the issues are.

 

Indeed; free and easy troubleshooting is good. Instinct tells me however that it won't tell you what's bad, only, that the heater is capable of heating. Eventually.

You may also have the problem wherein somebody mixed green antifreeze with the orange, and now the heater core is full of jelly.

 

Agreed. But, if the engine finally builds some heat with the (free!) cardboard test, and the heater still isn’t up to par, then she knows that it’s a heater core/heater hose/diverter valve type of issue. If the heater does in fact make some heat, she will need a tstat.
A good heater core flush on any older vehicle is never a bad idea, low pressure of course.

 

You can use air pressure as long is you don't over do it!

 

The threads I could find regarding the LT1 cars from 1997 back to like 1992 I think, All indicated a garden hose with a squirt gun on the end is enough pressure to unclog the heater core if that in fact is the problem.
Now I do not know what the doofus that I bought the car from did but there were a LOT of things done and wrong with the car when I got it. The best was the line he fed me thinking i am some dumb B1tch the conversation went as follows:
Me = " Where is the stereo? The photos on Craigslist showed it had a Pioneer double din 7 inch color screen Android Auto/Apple Car Play appliance in the dash? Nothing in the ad said that the stereo was removed"
mook= "Oh yes the stereo was broken so I removed it"
I thought to myself, SELF, he is LYING through his teeth, if the stereo was Broken who on gods green earth would go to the length of removing it? If its broken its broken and you just leave it for the person buying the car to deal with or get fixed etc.
He made the mistake of telling me he tried getting 12K then 10K and I got the car for 6600 bucks. So I think he was desperate and trying to minimize his losses by yanking the
Sun Visors on Passenger and drivers side out.
Floor mats,
T Top Shades,
Front license plate cover
Stereo
SLP intake lid and K&N Filter
Hurst Shifter and Ball ****
The guy looked like he tried to remove the headers and exhaust but the bolts were probably put in by an amateur who does not know what Anti-Seize thread compound is, and the header bolts look fresh tool marked up and probably could not squeak them out without having to drop part of the frame or lift the engine up a bit, So looks like he put them back and gave up.
Among other things he tried to strip out of the car to probably sell on ebay or something.
So I need a stereo cause I love to hear the car run and wind up the RPM's but its been 4-5 months now with no stereo and honestly I need a stereo so I need to take care of that soon.
Anyway I will test the heat today or tomorrow, the rain stopped but the wind is really kicking so I dont want any cardboard I try to cut and stick up in the radiator cavity blowing down the street into the neighbors yards and I have to run down the street chasing cardboard sheets like a jackass......But I think this is a fantastic idea to start with to see if any heat is capable as the car sits as is now. If I have to get invasive then so be it, but at least I can determine if its able to provide heat by getting the engine temp up to around 200 ish degrees and determine if the lower 160-165 degree thermostat is causing the issue or if its clogged or both. Now when I replaced the thermostat and the radiator I used the proper dex cool material and mixed it appropriately and what came out was Dex Cool as well, although it looked proper aqueous consistency that does not mean at some time prior the GREEN stuff went in or Dex Cool went in that was meant to be mixed 50/50 with water and no water was added so it turns to chewing gum jelly ice cream goopy snot crud. So i will reply once I get this tested and determine if the car can make heat and its my fault for putting in a low thermostat or whatever might be the problem but I will find out and know what to do next.
Thank you again for all of your help and suggestions.

Jenni

 

Going with a higher thermostat may just be the ticket and your absolutely right as there's no telling what the guy before you did to the car either. You mentioned changing the radiator well just maybe the radiator leaked and he decided to put some additive into the system and in doing so clogged the heater core. Best of luck to you and I hope you figure it out so you can report back as inquiring minds will want to know and it gives the thread closure.

 

If you're still looking for answers try flushing the core first. I'm a tech and have to do it on many cars every winter. It's pretty common for them to get a little clogged up.

165 degree stat is close enough to give you some heat. I've had to deal with this a lot of the last 20 years