Ok, the heater core is busted. For the time being I have bypassed it from the system. I have no fricking heat in the mountains of Western MD. I dare not use radiator stop leak in the radiator, as I believe it to cause detrimental affects to the engine.. But Im considering using stop leak in just the heater core itself and running a garden hose through it to circulate. Sound like a plan? How well does the radiator stop leak work? I have no idea how bad the damage is to the heater core, as I really dont have any desire to take apart the dash to remove it. When it was hooked up it leaked a fairly substantial amount, but it seemed to be sporadic.

 

ive used Bars Leak at least 2 or 3 times and it worked great (compression leak/headgasket).
i'm not sure how well it will work with cold water from a hose as opposed to warm water running through the engine, or how it will work to try and plug a leak in the heater core...

 

If I were to use one, Bar's is the best. Only word of caution, I believe the stop leak uses the heat of the coolant to fuse the sealing material together.

 

Thats what I thought Swarrik. Oh hell, I may as well replace it, I dont have a service manual for the blazer (have one for Camaros/firebird, Cougars/thunderbirds and Suzuki Vitara/tracker), dont suppose you can give me an idea of what needs to be taken off to get to it.

 

Live near a library? You should be able to check out the service manual from any decent library.

 

Decent library?? HA!!! I get your point though, that difficult? I can bum an S-10 service manual from somebody, but as for decent libraries in this town, I wont dignify it with a response.

 

its not difficult but it is a PITA.
generally speaking, pull out the under dash plastics on the passenger side, pull the heater core cover, and yank the old one out. i think i also had to unbolt the dash itself (one bolt under the bottom corner) on the passenger side and pull it back a few inches for clearance.
its just a hassle because the screws arent all easily accessable/seen. you have to pull the stereo out as well as the glovebox to get at all the heater core cover screws.
IIRC. i think it took me a few hours to do it.

 

Heater core is easy as hell to do on a 1st gen ESPECIALLY when compared to a 2nd gen heater core. Alls you have to do is roughly:

Take off passengers side kick panel(s), pretty much anything under the dash and to the right of it.
Unbolt the PCM and drop it down.
Take out the access panel in the glove box.
Take out the radio.
Remove the 6-8ish bolts holding on the heater box
Remove 3 of the 4 bolts on the straps holding the heater core in the box.
Get vice grips and pinch the inlet/outlet parts of the core in the engine bay completely shut so coolant doesnt get all over your interior.
Cut off the old hoses and pull the heater core out.

Reverse installation, the other part where I needed an extra set of hands was putting the new hoses onto the core, I had a buddy of mine hold the core steady while I pushed the hoses on and that's pretty much it. Definitely not as bad as everyone makes it out to be.

Certainly you can take off the entire dash board but I don't recommend it, I did that the first time I did a heater core in my 89 and it was a 2 day nightmare and the dash never fully got back together so don't make my mistake. The core is only $25 from Advance Auto and well worth it for a non-leaky and fully heated Blazer. Good luck!

 

Thanks, I ordered a heatercore from autozone, supposed to be here today. 25 bucks, the kid working at the Autozone, I knew him from high school. Odd, I didnt think he was the "car person" type. Guess they hire anyone at those places. Then again, I think most people think Im a computer nerd, very far from the truth. Anywho, Im looking forward to this [:@]

 

Nice writeup Chris! Thats some great time saving information right there! Us 2nd gen guys don't get that lucky.