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2002 lesabre heat


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dr.donut
User

Oct 3, 2015, 2:02 PM

Post #1 of 11 (929 views)
  post locked   2002 lesabre heat  

Have a 2002 buick lesabre auto tranny with a 3.8 engine that would have heat and then it would not, don't think it's an air pocket because the hoses at the firewall are hot and I bled the system through the nipple at the thermostat .I removed a few panels under the dash board and have the plenum hanging from a tab on the pass side that I can't get loose. Once I do the box the core is in would be accessable,I'm wondering if there is any thing I can check as far as relays or actuators that open the valve. Something that doesn't require access to the heat core itself, any help would be appreciated.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 3, 2015, 2:38 PM

Post #2 of 11 (925 views)
  post locked   Re: 2002 lesabre heat  

I'll take this as heat is intermittent and let's start with that.
Why did you bleed out air from cooling system and did it in fact bleed out air? Were you doing something that involved coolant or overheated or anything?


In short - you MUST know it's really full and if it wasn't for no reason mentioned yet that's the first thing to be concerned with,


T



Discretesignals
Ultimate Carjunky / Moderator
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Oct 3, 2015, 2:57 PM

Post #3 of 11 (916 views)
  post locked   Re: 2002 lesabre heat  

Is this manual or automatic HVAC?





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dr.donut
User

Oct 4, 2015, 5:14 AM

Post #4 of 11 (898 views)
  post locked   Re: 2002 lesabre heat  

Yes the heat was intermittent and now there's nothing. I originally bleed it because of a code that came up, "low coolant" and I assumed a sensor was detecting low coolant, as it turned out a better diagnostic said low coolant temp. because the new thermostat I installed opened at a low temp. which I think is ridiculous and only served to be a pain come inspection time, here in the vampire state you don't pass if there is a code up.I bleed it with a tube over the boss for the nipple so that no air could get in, and I found no air bled from that endevour.Also the hoses at the fire wall were hot so the problem must lie with the core or valve in the cab. As far as whether it's manual or auto I don't know ,I can't get a look at the workings .From a you tube vid. I would say auto air, but those guys took out the whole dashboard to replace the core on a 05 buick lecerne.. Many screws were removed but I'm still facing a plenum that seems to be loose enough except for a tab on the end that I can't slide it free from,if that would come out I could get at the rest. I'm working with a small mirror to even see that. I'm ready to button it up and bring it somewhere but I'm one of those people that like to DIY and keep the 100 dollar bill for me.Thanks much.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 4, 2015, 6:25 AM

Post #5 of 11 (896 views)
  post locked   Re: 2002 lesabre heat  

Quote you ">>because the new thermostat I installed opened at a low temp.<<"
Whatever reason you did that possibly thinking it would help a hot running engine it won't and is the secondary upfront problem now IMO.
What you probably have is something like a climate controlled HVAC system. Some (can't speak for all of them) for heat would not blow anything at you until up to temp and if hovering around that line would quit blowing what it thinks can only be annoying cold air at you.


Everything smacks of this car runs hot and you chose a thermostat of a different rating to fix that and it can't but no maybees, WILL cause problems. Not just for heater but if engine is telling its computer engine is cold or a given temp you could be running into open and closed loop confusing the thing on an assortment of engine controls.
For whatever reason you deviated from the suggested temp spec for the thermostat it has to be changed back. If nothing was wrong and you thought it would help something for some unknown reason it isn't.


If overheating for any reason suspected or consumption of coolant you find out why first then deal with this. It will always be critical to know system is properly filled if coolant level is involved for any reason too,


T



dr.donut
User

Oct 4, 2015, 6:43 AM

Post #6 of 11 (893 views)
  post locked   Re: 2002 lesabre heat  

The thermostat was changed as a preventive measure, I removed the old one, flushed the system and installed new and it was what that model called for, the car does not run hot and never did. The low coolant code is not there anymore and would only come up once a month or so when it was there,, the stat was from car quest and perhaps they got it wrong or theirs is low quality, the heat has been intermittent for some time and now we got nothing.I can't say if it is auto/manual or what,it's not a cable, you slide the little knob and it run elec. ?or by air? don't know, can't get a look at the core or it's workings.There is a code for small evap. leak.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 4, 2015, 7:22 AM

Post #7 of 11 (892 views)
  post locked   Re: 2002 lesabre heat  

OK - Perhaps I misunderstood you? You asked for and installed a new thermostat as a preventative measure - OK. I don't unless there's a reason but fine most would.


Is that correct to the temp you really need to check housing with a touchless infrared thermo for a good idea or toss it again but you can watch that one in a pan of water with a good thermometer open at temp which should be stamped on the thing so no mix ups just from the package it came in.


Quality can stink in many things - can't help that from here. IDK - Fav once was RobertShaw for thermo anything then Stant now Stant or who owns them bought out RobertShaw? $$ rules - if another can do it cheaper they will - customers suffer.


So - There was nothing wrong with the heater I take it till you changed thermostat - right? So why are you looking under the dash? Instant problems or soon when something done you should suspect what was just done first and so do I still.
Thermostat may not hold temps in ranges car can deal with and still could have air. Some are a real pest if you drain a cooling system to the point you need to vacuum fill - machines most wouldn't have or access to. Hard on the DIYer without on some.


What type of A/C controls? It's a Buick! Most would since forever try to do you favors and come with features other makes might not. There really is a system to stop heat if it thinks it isn't warmed up enough usually just blower slows or doesn't blow at all but would on vent or defrost request usually. YOU need to know the operation of your specific vehicle's way of being NORMAL behavior. Owner's manual should discuss this well and if not the case at all back to air or temp isn't right.


Sounds like you just wanted to do a preventative things and that's good but that didn't work out in this case not something else yet right now,


T



Discretesignals
Ultimate Carjunky / Moderator
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Oct 4, 2015, 8:57 AM

Post #8 of 11 (886 views)
  post locked   Re: 2002 lesabre heat  

It has to have the corrected rated T stat in it. You don't want the engine running too cold because it will flag a P0128 and some emissions monitors won't run. You'll also have reduced heater performance and the engine will use more fuel.

Don't know why your ripping the whole dash apart just yet. You don't even know what is wrong. If you have slider controls, you probably have manual HVAC. Automatic HVAC has a vacuum fluorescent display. With the key on and engine off, you should be able to hear the change of pitch of the air inside the HVAC case change as you move the temperature slider with the blower on high. That will tell you if the blend door is moving.

You can also stick your hand up under the dash and put your finger on the side of the actuator. There is a shaft with notches cut out. When you move the temperature control, you can feel those notches move at the shaft spins. That is another way to tell if the actuator is functioning.







Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Oct 4, 2015, 9:21 AM)


dr.donut
User

Oct 4, 2015, 12:55 PM

Post #9 of 11 (872 views)
  post locked   Re: 2002 lesabre heat  

there is no change in the sound of the fan when going from cold to hot setting, there is a "wheel" that pivots to turn a lever, it will go one way and then back when you turn the key on engine off, it only does it when you turn the key on ,going from cold to hot doesn't affect it. I'm trying to visualize the diagram posted then go down and look under the dash, it will take more time and effort. 5 or 6 years ago gramma had the car and she lost heat and then took it to the shop but I've no idea what happened there, john edwards may be able to help with that.thanks again


dr.donut
User

Oct 8, 2015, 12:50 PM

Post #10 of 11 (841 views)
  post locked   Re: 2002 lesabre heat  

It was the actuator,(module) for $70** at the dealer,$100** labor, they cleared the EVAP code and said to close the gas cap


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Oct 8, 2015, 5:13 PM

Post #11 of 11 (832 views)
  post locked   Re: 2002 lesabre heat  

Not sure if you have to rip the whole dash out for that one. Maybe the lower IP? Good to see it is figured out. Thanks for the follow up. Closed as solved. Can be reopened by request from the OP.

Smile





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Oct 8, 2015, 5:15 PM)






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