98 Blazer heater core replacment (I just did it)

[Vito_1502]

Just helped SIL replace the radiator which had a crack on the left side tank. We got everything back together, refilled system and cranked her up.

Wouldn't you know it...coolant coming out of the drain tube for the A/C box...so now we've got a leaking heater core to deal with too.

Gonna quickfix for now (copper pipe between the heater hoses to close the loop) and then come back to address changing out the heater core.

Very good instructions posted on this procedure to avoid the pitfalls and head scratching sessions. We'll try to get some pics done when we tackle it next month.

[BryceA]

Well to all who have posted on this topic, I thank you. I’m midway through my heater core and evaporator replacement. I am not racing through it, just moving slow and precise as I don’t want to have vacuum & electrical problems when I’m done.

This is a BIG job! I’ve taken dashes out of other cars, but this one is especially tricky, and if you don’t have a KILLER set of tools you shouldn’t try it.

I can’t see how to get the heater core out with removing the box (but this is a 2000 blazer). I opted not to cut/dremel the tabs on the floor; it was tricky to get the 10mm nuts off of the studs in the firewall around the passenger’s exhaust manifold, but possible. Again, you need the right tools to do this. (I cut a ¼ inch 10MM deep, to just barely just usable 6 point depth ~1 1/16” then used a “drill bit to ¼ inch drive” adapter, and a straight ratcheting wrench for ease. It took more time to make the tool than it did to get it out. – I just didn’t want to risk rattles in the dash.)

I have only the last bolt in the evaporator box and will be removing the Evap box and replacing the evaporator while I’m this deep into the project.

When I get all of it out, I’ll post some pictures of the boxes, to hopefully assist someone else in knowing where all the mounting bolts are.

For the record… I wish I would have just taken it into the dealer and paid the money to have them fight with it, and warrantee the work…

P.S. If my new heater core goes bad in the future, I’ll be figuring out a cool method to total it.


--Bryce
2000 Chev Blazer 4WD 4.3L (money/time pit!)

[jcnfh]

Oh my god.

I cannot thank everyone who contributed to this thread enough.

I just spend a goddamn day witha worthless piece of shit Haynes manual trying to do this stupid repair.

THANK YOU THANK YOU THANK YOU


I dream of meeting the man responsible for the design of this heater core some day, and punching him.

[Phil Albert]

From Previous Post -
Ok, so the first thing to do is remove the one heater core box bolt that is under the dash on the passanger side behind the carpet and cut the two black taps with a dremmal on eithe sided of that bolt. Next remove all the undash plastic, [COLOR=blue !important][COLOR=blue !important]glove [COLOR=blue !important]box[/color][/color][/color], front dash cover and insterment cluster. Next on the driversside there are two 90deg angel brackets under the stearing colum remove them (4 screws) also there are two screws on the lower part of the dash one one each side near the floor next to the door that need to be removed. After that you need to remove the speaker covers and the defrost vent cover to access the screws that will lossen the dash I think there are 6 screws. Once they are removed the dash will roll back. You need to disconnect all the wire harneses that are connecting the dash to the fire wall so the dash can be pulled out farther. (I found that tilting the dash just did not work there was not enough room to work.)

Ok time to remove the heater core in the engine compartment there are two bolts and one nut. The nut is right next to the hoses that go to the heater core. One bolt is just to the left of the distributor below the heater core supply hoses. the other bolt is the hardest bolt to get to it is in the A/C evaporatior box where it says cut here for service so get in there and lossen that bolt and the heater box comes right out on top of the hater box there are two screws that are holding a cover over the hater core remove them and that is the core. To reassemble just do it all again backwards.

The total project time for me was 5 hours. It would have gone alot faster if I had some swivel sockets and longer extensions. I hope this helps you. WHAT EVER YOU DO DO NOT ATTEMPT TO SPLIT THE HEATER BOX THERE ARE SCREWS GOING ALL AROUND THE BOX AND YOU WILL MORE THAN LIKLEY BREAK THE BOX AND AHVE TO REPLACE IT. THERE ARE PEOPLE SAYING TO SPLIT THE BOX ON SOME POSTS BUT THAT DOSENOT WORK ON A 1998 BLAZER.

GOOD LUCK I HOPE THIS HELPS YOU I DID 4 DAYS WORK OF RESEARCH TO FIGURE OUT HOW TO DO THIS REPLACMENT.

Is this the same as a 99 s 10

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99 S10 ZR2 -

Excellent Description - from previous post!!

I would add the importance of cutting the 2 plastic tabs, on both sides of the bolt, bottom right hand side of the heater core box, folding down the carpet! Otherwise, your having to pull the fender etc... to get at them, and there's really no need for them to hold your heater core box in place! Definately a time saver!

This is an engineering disaster! $860 is what I was quoted from the chevy dealership! Rediculous!

The 'bastard' bolt - previous description - is definately not fun! This is not for the faint of heart! That is for sure!

Also, if you don't pull your stereo, to disconnect the antennae cord, or the power line, from the stereo to the tape player, you won't be able to pull the dash out! I left them in and was able to get the dash, sitting on the seat, far enough back to get at the heater core 'box'. But, there's just barely enough room to work, otherwise.

I just got the heater core box, back in. Thought I would reply, taking a little break, before putting everything back together!

12 pack of beer, isn't enough, by the way, with lots of F-bombs! Plan on a good long day in the garage to complete this project!

Phil

[Elizabe2th37]

Ok time to remove the heater core in the engine compartment there are two bolts and one nut.

[Leslie508]

has anyone replaced thev core on a 91 s10 pickup