Heater Core (Oh Sh^t)

[M. Grogan]

I have a 99 H1 open top that has been very good to me over the 4 years that I have owned it. I noticed this weekend that I was getting an anitfreeze smell inside the vehicle coming from the vents. I now have a small amount of antifreeze dripping from the vehicle that is running down the back side of the front right wheel well. It is hard to access, but appears to be coming from the small 90 degree elbow tube located just above the heater hoses running down under the body to the rear a/c unit.

I'm thinking I have a heater core going bad but can anyone suggest any easy fixes or other things that could be a simpler fix before dropping $1500 at the dealer?

I can fix most anything on my H1 but after reading the service manual procedure...I wont be messing with this repair if it is a heater core problem.

Thanks.

[lvs]

Check here:

http://www.hummerknowledgebase.com/interior/core.html

[ssgharkness020147]

Heater cores are a real pain in the ass. FWIW, I would stay far from the dealer for that repair. 1500.00 is probably the minimum you'll be spending on that repair. When mine went I was feeling a bit lazy so I had my local shop replace it for me, the part was 320.00 and the install was only 475.00. All in all thats not too damn bad.

[M. Grogan]

lvs, the blow by blow on the install was very helpful. I've handled most of the service on this vehicle myself up until this point but this sounds like something that I may not want to get into.

Is there anything unique about this repair that makes it different from a run-of-the-mill heater core replacement on a diesel truck? If not, I may explore the local shop option.

Does anyone have a good cross reference number for the heater core itself?

[ssgharkness020147]

I read the rebuild instructions when mine went, like you said it doesn't look too bad. But, I was feeling lazy so I opted out. The thing you need to remember is that HVAC unit which needs to come completely out has the AC condenser in it, so the AC system needs to be purged. The HVAC unit itself is all glued together with a black RTV (like) sealant. I know in my case the mechanic hated that, being fragile plastic you need to be sure to be very careful when disassembling it. As far as a cross over part # goes, there is none. Either you get it from HUMMER, or you have one custom made. The core you currently have could probably be repaired by an competent automotive HVAC shop.

[JustinOK]

There is no parts cross reference for the heater core; it is made only for us. I bought mine from Dave Breggin for I believe $388. You'll also need a few gaskets/seals. Since you have to drain the coolant, I also swapped out all of my radiator and heater hoses. Not a bad move for you either, since your truck is 9 years old. NAPA can definitely get you some hoses for a good price. I bought mine from Dave B as well. I think it was close to about $120 for all of them combined.

I did my heater core in late March. I'm new to turning wrenches and I was able to do it with relative ease. Of course, I got some hints from Chuck's site and the HML/HKB. Took my slow ass about 14 hours to do it.

Feel free to PM me with any questions.

[JustinOK]

BTW, it can be bypassed relatively easily, too. But being that you are in VA, you'll probably need your heater soon.

[BigKofJustice]

Ugh. I hate the 5 password entry system here... anywho..

Heater core is labor intensive to a certain extent. I had mine done at the dealer, heater core alone ran about 700$ parts and labor [4 hours labor 300$ for the core] which was reasonable.

Turned out my hvac system was full of dirt and mud, and while everything was apart I decided to have a new condenser , blower and gaskets installed in addition to a new manifold on the firewall plus a new dryer. Ran me about 1500$ for a rebuilt hvac with warranty.

My heat/ac is awesome now.

Heater cores are a problem in trucks from the desert states. The owners never usually run the heater, so water/coolant builds up and never gets flushed out of the system, so it sits and corrodes the core.

[Ground hawg]

the only problem I had doing mine was removing the bolts from the bulkhead manifold. it's alluminum and the bolts are steel after 9 years they might not come out without breaking. so be prepaired to drill them out very carefully.

[JustinOK]

Originally Posted by Ground hawg

the only problem I had doing mine was removing the bolts from the bulkhead manifold. it's alluminum and the bolts are steel after 9 years they might not come out without breaking. so be prepaired to drill them out very carefully.

Blow torch baby. Heat the bolt head up and you should be able to remove normally. I did that for two on mine.