How-To: 2005 Silverado Heater Core Replacement.

[jaded13640]

05 Silverado Heater Core R & R “write up”

 

I was going to do a step by step write up on this job, as I’ve just done one, but I don’t see how I could do a standard “step by step” write up.

 

Basically, it’s a HUGE pain in the azz! EVERYTHING has to come off the dash before you can get the dash away from the firewall. So I’ll do my best to cover the things that I ran into while doing the job. This was the first one I’d ever done on this model and the biggest problem I ran into was that there was very little “how to” information out there. The “online manual” that I have was so generic it was useless. It basically said to “remove dash, remove heater box, replace heater core, re-assemble in reverse”. It really didn’t get into how to do any of those things.

 

Since you’ll be messing around with wiring and an airbag you’ll want to disconnect the battery cable.

 

First off, there is no coolant drain in the radiator. You’ll have to do it the messy way. I just pulled the heater hoses and let them drain into a pan for a minute and then laid them over the engine so they couldn’t drip. To get them off you have to use a “quick release” tool, similar to a fuel line disconnect tool. I have the strip of plastic ones. You have to use that style because they have to be longer than the typical fuel line release type tools. First I twisted the connector on the heater core tubes enough for them so spin freely. Without doing that you’ll probably just break your plastic release tool. Once the connectors spun fairly freely the tool slipped right in there and released the connectors fairly easily even with a 275k miles on it. One of the hoses is held to the connector with a pinch clamp. I removed it and the hose just to make life easier. That one’s up to you. But the connector won’t fit through the hole in the fire wall so even with the hose off, you’ll still have to remove the connectors.

 

You’ll have to evacuate/recover the refrigerant and disconnect the evaporator as it’s in the heater box. I think I had to remove the filter/dryer AND it’s bracket to gain access to the heater box fasteners. In fact I think two of the heater box fasteners ARE the filter/dryer bracket fasteners.

 

There are about 7 or so screws that go through the firewall and hold the heater box to the firewall. You don’t need to remove the one that holds the cover for the condensation drain for the heater box. It doesn’t go through to the box. There’s one fastener way behind the motor that you may miss. Just be careful and make sure you don’t miss any. At this time you may want to remove most of the screws but I would leave a couple in until you get the dash portion of the job done and then come back and remove the last couple of heater box screws. It doesn’t matter if you start inside or under the hood but given that the coolant has to drain, you’ll probably want to at least remove the heater hoses first.

 

When you get to the dash portion, I really don’t have a step by step to give in this case. I just kept removing what appeared to be in the way. It turns out almost everything has to come off the dash.The trim around the instrument cluster, all the controls, the radio, the passenger side air bag, passenger side airbag disable switch, instrument cluster, kick panels a pillar trim, the glove box, the two vents on either side of the pull handle…EVERYTHING.

The wiring was pretty tricky too. LOTS of connectors have to be disconnected. The harness section that is in about the middle of the dash, well, it would be very handy to take pictures, label connectors etc. I ran into a little confusion when I replaced the radio and all the crap in the middle there. The connectors have to go back through the exact same holes in the plastic substructure or they won’t reach the components. There’s a structural bar that everything mounts to and it mounts to the body on the passenger side. I think it has to come completely out so that there’s room to get the dash back far enough and so that the heater box will come back from the wirewall enough. The thing to watch for when removing that bar is the wiring harness. It kind of wraps around it and some wires go over and some under. I evidently didn’t pay close enough attention when removing it and couldn’t remember what went over and what went under. So take a picture, write a description etc. It was a pain getting it back right.

 

There are a few little things that I didn’t know until I got into it and I’ll try to focus on those as the rest of the job is just taking every damn thing off until you can get the next damn thing off and so on and so on. The glove box is screwed to the lower rail of the dash but is also held with a couple of rivets. You’ll have to drill the rivets out. They’re soft and will be gone in no time.

 

Another big thing I didn’t know going in was that the “jesus handle”, the pull handle on the passenger side of the dash above the glove box has to come off but isn’t as difficult as I thought. Little did I know that there are two little plastic buttons that release the handle but you can’t see them and wouldn’t know they exist until you remove the heater vents on each side of the handle. With the vents out you jus t push the little buttons in, might need to push them with something if they’re stuck, and when they pop in, you can work the handle, one side then the other, back and forth and it come right out easily. I probably lost an hour on that one because I didn’t know the button were behind the vents. I had also already removed the passenger side air bag and I think it would have been easier to do had I pulled the vents out first.

After all the controls and crap are off the dash and all the trim and panels and such are off you have to remove the pull handle and remove the dash pad before you can access the screws along the windshield in order to pull the dash away from the firewall.

 

By the way, you’ll also have to drop the steering column. You may benefit from, using a strap or something, holding the column up a little. Otherwise it lays right on the lower rail of the dash and makes things difficult when you go to swing the dash out and back in.

 

After all the controls and trim are off you’ll have to take a gob of screws out of the plastic substructure that all the controls and everything mount to. There are two studs on each side, at the area where the dash mounts to the body, that have to come off as well. There are metal braces across the top of the dash after the pad is off that hold the dash pad up and keep the heater venting tubes from moving around. They have to come off too. I probably removed more than necessary but again this was my first one of these and I couldn’t find much “how to” info.

 

I don’t recall there being many if any support rods/brackets holding the dash to the body/firewall but the brackets that the “knee panel” below the steering column had to come out. You’re going to find that stuff you wouldn’t think would need to come out, do. There are two of those brackets, one on each side of the steering column that have to come out. Once the screws are all out of the plastic sub structure things will move around a little and those brackets will, after being unscrewed, work out. Fortunately most of the screws are the same length. As with any job it’s important to note that different screws and bolts and nuts go in different places. Some were hex head, most were Phillips.

 

There are 5 or 6 bolts that hold the main dash structure to the body. There are three on the passenger side and two or three on the driver’s. If everything has been removed and or sufficiently loosened you’ll be able to swing the dash out enough for clearance for the heater box.

 

Despite what you may have heard or read you do not have to completely remove the steering column or the dash or the heater box.

 

Once the dash is swung out and all the heater box fasteners are off the box will move out far enough to see the heater core cover. There are only two, maybe three screws holding the cover on and with the dash swung out you can just lift the heater core right out. There’s a strip of foam wrapped around the heater core and the new one didn’t come with any. You may want to get some weather stripping for that. I wrapped the old stuff around it and taped it but only because it was too late to go out and get some weather stripping to replace the old crappy stuff.

 

You’ll find that you’ve got an enormous amount of time into accessing the heater core and putting everything all back together but it only takes like 5 minutes to actually change the heater core once you have access.

 

This is going to be a very long and frustrating project. Leave yourself lots of time and be prepared to be patient. There are a lot of stupid and frustrating things you’ll have to contend with on this job but it’s really just a matter of taking apart what you need to in order to change a part. If you’re a mechanic or a do it yourselfer you're already used to this stuff. This is by far the most miserable heater core I’ve ever done but the shops get maybe $800 bucks or more to do it.

 

Take your time re-assembling everything. There’s a lot of pieces laying there when you have it all apart and they all have to go back in the right order. Since you’ve evacuated the AC you’ll have to vac and recharge it or take it in and have it done. Of course you’ll have to top off the coolant and cycle it a few times to burp the air out.

 

The labor guide only lists like 6.7 hours to do this job which is stupid. Even if you work in a dealership and do nothing but heater cores on this truck all day every day, I don’t see it happening in that amount of time. I do this for a living, I’ve been wrenching for almost 40 years, have every tool you can imagine, air tools, special tools, etc. and it took me 3 days. If you can do it in less, more power to ya.

 

I covered a lot of ground and there’s just too much to get into every little detail. If you have any specific question about something just send me a PM and I’ll do my best to help you through it.

 

Best of luck,

 

Wayne

[txab]

[ScottyBoy]

Great write up. I think I will probably have to do this soon on my brother's 2001 Tahoe next time I go down to his house. His heater core started leaking and he ended up having someone just bypass it for him. It would probably be a good idea to replace the evaporator too if that has to come out, since he needs a new AC compressor too. I was planning on helping him with that as well.