Bought the replacement at the new O'Reilly's parts store that just opened up on Rt. 1 in Chester, VA.

Got the old one out and the new one wasn't made quite right. the "tank" on the driver's side did not have the dip in the middle to clear the clamp. Instructions said to use the supplied self stick foam tape pieces to pad/insulate/secure the core inside the plastic housing.

I took it back to O'Reilly's to see if they sold another brand that fit like the original but they did not. They recommended NAPA or the Chevrolet dealer. For what its worth the picture of the heater core on their computer showed a correctly made part but what was in the box (the guy went back and got another one off the shelf and it was made wrong, too.

Not being sure how long said stick on foam strips would last before they started deteriorating I went to the Auto Zone parts store across the street and got one that was made like the original. The incorrectly made replacement will go back to O'Reilly's tomorrow on the way home from work.

FYI in case you need to do the same job some time.

 

interesting

my GM unit leaked after 4 months and my Adv auto unit with the foam works fine. The pipes can be moved and the unit fits fine

 

I have a 91 rs that I want to do this to. How hard a job was it. I read the procedure. Sounds like just some of the screws on the enclosure are hard to get to. I was planning on buying from Napa. Always felt that Napa was equal to OEM.

 

level of difficulty is a relative term and based upon your skill level and confidence.

I did not think changing the heater core was difficult at all. But then again, I go through life dizzy so working upside down to get to 2 screws was quite normal to me

the 2nd time in 4 months that I replaced the core I used one from adv auto. My GM version which i used the first time leaked all over my new carpet.

 

I'll most likely keep the one from O'reilly's. My IROC is 26 years old now and sooner or later that heater core has got to go. I've never had one last tht long before.

 

Don't be afraid, aftermarket heater cores are made a bit "simpler".
I've bought Proliance heater core and also was surprised - it has no dip in the middle for clamp but when you put your heater inside heater box it will fit correctly!

 

I got a HC from Summit and it didn't fit. Instead I put a small cooler in it's place. It doesn't make as much heat, but It did allow me to run 3/8" hose, which I like.

http://www.summitracing.com/parts/DER-13212/

 

theres basicaly 2 versions of replacement heater cores for our cars, the one you got with the slightly different tanks, and an exact copy of stock. you can make the close to stock one fit (i know its the one in my car now) or you can keep trying them from various places until you get the right one. they show as the same part number IIRC.

 

I'm doing this same job right now on an '85 T/A. I bought the core from AutoZone. It's a Spectra Premium and has that same dip between the two tanks for the clamp. My only complaint, which is just a niggle really, is that it is slightly smaller than the original Harrison unit. It is maybe an eigth of an inch narrower but otherwise fits just fine. Cost was $28.

 

i just replaced mine in my 91. i bought a replacement from auto zone, $28. aluminum, but correctly fit in the mount and into the firewall. the only issue was i had to switch to a 5/8 hose from a 3/4. switch out time was about an hour. i didnt need to remove the dash cap either.

 

Doing mine today and was surprised to see the aftermarket one would not fit in the housing. Hopefully from what I hear it should go back in with no issue. I guess you do not use any of the original mounting tabs?