Heater Core

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mstorrs

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Have a 2000 Jimmy Diamond Edition that needs the heater core replaced. How easy is it to get to this part and do you have to take the whole dash down?
 
mstorrs said:
Have a 2000 Jimmy Diamond Edition that needs the heater core replaced. How easy is it to get to this part and do you have to take the whole dash down?
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Sorry for the bad news, but yes you are correct. Your going to have to drop the dash to be able to replace the heater core. :eek:

Good luck and keep us posted.
 
Heater Core Replacement

So exactly how long do you think it well take to do this? Just curious.
 
mstorrs said:
So exactly how long do you think it well take to do this? Just curious.
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Takes about 4 to 5 hours, taking your time to make sure yuo don't break anything else. Take pictures so you can use it for reference later when putting things back together.

Here is a link that should help you understand what your getting in to, but worth your time on doing the job your self with common tools. ;)

Good luck and keep us posted. http://www.ehow.com/how_5306495_change-heater-core-chevy-blazer.html
 
So i have taken the dash down competely. Only thing left is the big black box in the middle. Are there screws on the firewall (on engine side) that i need to take loose to remove the housing unit where the heater core is located?
 
mstorrs said:
So i have taken the dash down competely. Only thing left is the big black box in the middle. Are there screws on the firewall (on engine side) that i need to take loose to remove the housing unit where the heater core is located?
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In regard to removing the "black box" around the heater core; make sure you remove ALL the screws, there are a couple on the left side that can be hard to find. I suggest using a flashlight to look around the edge and make sure you get them all. Then pull gently in a tugging fashion; pull, let loose, pull, let loose, as the seal can make it kinda not want to come loose, just be delicate with the seal. after you get the box off there are five screws for the core itself, 2 on each bracket and one that holds the bracket that holds the pipes in place. BE SURE you re-install the pipe bracket securely or you may damage the core when you reinstall the hoses. http://i219.photobucket.com/albums/cc131/Baggusamongus/Envoy-heatercorereplcmnt017.jpg

Now, some have said that there are 2 10mm bolts to remove behind the passenger side fender and recommend dropping the fender just enough to get to it. Looking back, I couldn't see a reason to and in hindsight I may have wasted time doing that.

If the heater assembly won't come out and everything else is loose feel free to do that.

Instead, Try to just get the 2 screws on the engine side firewall by the heater core connector (one on the right and one on the left/bottom area besides the evaporator cover) as well as the bolt in the evaporator by cutting and using a ratchet wrench. Keep in mind that there is also another 10mm bolt on the cabin side of the firewall under the heater assembly that needs to come out.

Now, there are two tabs - one on each side of the 10 mm bolt cabin-side firewall under the heater assembly. It seems the bolts can be wrenched loose on the engine side of the fire wall. Instead, most people tore those bastards loose. Don't do use a dremel as you may have a hell of a time getting the heater assembly back in line to get the bolts back in and torn tabs make it all the more harder. It's a good 2 more hours trying different ways to get that damned bolt to thread cause the tabs were in the way and would seat right as would a strait rotary cut would have.

With everything loose you should be able to pull out the heater assembly by disconnecting a few choice vacuum lines and some more connectors. The cooling line connectors on the new heater core will have some play so you can get it in there correctly. Make sure that you hook the two vent looking connectors going into the carpet before thinking the heater assembly is working your nerves. For some reason the heater assembly connects to the floor vents which in turn connect to mounts under the carpet.

Now just reverse what you did. Some things to keep in mind.

-The rear wiper/gate open switch wire can and will get caught when you put the dash back in. Keep it loose.

-There is a connector for the actuator motor on top the heater assembly against the firewall. Connect that before you bolt in the dash. I had small fingers and finagled it in by luck and prayer.

-Make sure you connect your courtesy lights for floor lighting back to the panels you took them off of.

-Your passenger side door sensor may or may not have a wire. Try to see if it does before you get started so you don't worry about it and take the dash apart again trying to find it before giving up wondering if it even existed.

-You will need a friend to help put that heater assembly back on the firewall to get all the bolts to thread. You will also need some dexterity to put that one bolt in the evaporator housing back in.

When you have everything back together again hook up your cooler lines to the heater core and open up the radiator cap/reservoir cap. Turn on the engine and make sure you get all the air out of your cooling lines.

The automatic Climate control may need to relearn temp parameters or at least it seemed to the first few drive cycles.

Keep us posted and keep up the good work. ;)

Here is a video of a 2001 blazer heater core replacement, slightly different. But it shows you where the bolts are located for the heater box assembly. http://www.compnine.com/index.php?u...1147577498&capuid=1&majorgroup=08&grouptype=B
http://www.compnine.com/index.php?u...1147577498&capuid=1&majorgroup=08&grouptype=B
http://www.youtube.com/watch?v=687B2pspF2w
 
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Now that i have everything back in place and working trying to figure out what causes the a/c compressor to keep clicking on and off when i turn the defroster on. Even when i switch the control to blow out vents it still does it. What could this be? Thanks again for all your help. everything was on point.
 
mstorrs said:
Now that i have everything back in place and working trying to figure out what causes the a/c compressor to keep clicking on and off when i turn the defroster on. Even when i switch the control to blow out vents it still does it. What could this be? Thanks again for all your help. everything was on point.
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Low on R134a can cause the compressor to click on and off, this is more common during the colder weather season. Best is to get your A/C system checked out by a shop. Try to stay away from the DIY recharge kit you can get at most Auto Parts store.

Over charging your system will give you less A/C performance and at worst cause you more $$$ if the compressor, or O rings fail due to over charging. The manifold gauge should be 250-300 on the high pressure side and 25-35 on the low side.

R134a low side pressure will be be slightly lower (27 PSI) on a 80 degree day and would see between 176 and 200 PSI on the high side of an R134a system.

Good luck and keep us posted, and it's common for you to lose some R134a though out the years of A/C service in your Jimmy from worn O rings.
 
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