Need help on heater core replacement for a 1974 Olds Delta 88 convert.

Tim Burleson · January 20th, 2007, 10:26 PM

Hello Everyone,

I just purchased a 1974 delta 88 convertible. 455/4bblcarb. The heater core is leaking. I need suggestions on how to replace it. Never done it before. Your help is appreciated.

Tim

Oldsguy · January 22nd, 2007, 06:53 AM

You need small hands! Actually, almost anyone can do it but it is a tight job. Most of the fastners are on the firewall, some are small bolts and some are nuts. Don't ask me why they do it that way but they did, probably for alignment. Anyway look at the firewall on the passenger side and notice a pattern of bolt head/nuts in a rectangular pattern, maybe eight on top a couple on each side, and eight on the bottom or at least something near there. There are a lot. They hold in the core housing which is on the inside of the firewall in the passenger compartment. You will have to remove all of those fasteners, some are a tight fit closest to the wheel well. You will also have to remove some stuff in the passenger compartment, probably the glove box and some air door controls ventilation hoses. Depending on the kind of ventilation system your car had they may be solid cables or vaccum hoses, hope for the hoses as they are easier. Label everything and take pictures or draw sketches. Once all the fasteners are loose you can remove the air box (plenum) from the inside and then the heater core comes out (from the inside), of course remove the supply and return hoses for the coolant too. Well that's about it.

Tim Burleson · January 22nd, 2007, 08:04 AM

Thanks Oldsguy,

I do have small hands and your information will be very helpful next weekend. This forum will be extremely helpful for me. Thanks for taking the time to advise me and do have a wonderful week.

Tim

Oldsguy · January 22nd, 2007, 10:00 AM

No problem! I don't have small hands and I end up with scratches all over the back of my hands.

Tim Burleson · January 22nd, 2007, 07:36 PM

Question: Can I temporarily bypass the heater core by taking the supply coolant hose and routing it directly into the return without harming the engine?
I need to use my delta 88 as a daily driver as I won't have time to change the heater core for several weeks. Thanks in advance

Tim

January 20th, 2007, 10:26 PM	#1 (permalink)
Tim Burleson Junior Member Join Date: Jan 2007 Posts: 3	Need help on heater core replacement for a 1974 Olds Delta 88 convert. Hello Everyone, I just purchased a 1974 delta 88 convertible. 455/4bblcarb. The heater core is leaking. I need suggestions on how to replace it. Never done it before. Your help is appreciated. Tim

January 22nd, 2007, 06:53 AM	#2 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	You need small hands! Actually, almost anyone can do it but it is a tight job. Most of the fastners are on the firewall, some are small bolts and some are nuts. Don't ask me why they do it that way but they did, probably for alignment. Anyway look at the firewall on the passenger side and notice a pattern of bolt head/nuts in a rectangular pattern, maybe eight on top a couple on each side, and eight on the bottom or at least something near there. There are a lot. They hold in the core housing which is on the inside of the firewall in the passenger compartment. You will have to remove all of those fasteners, some are a tight fit closest to the wheel well. You will also have to remove some stuff in the passenger compartment, probably the glove box and some air door controls ventilation hoses. Depending on the kind of ventilation system your car had they may be solid cables or vaccum hoses, hope for the hoses as they are easier. Label everything and take pictures or draw sketches. Once all the fasteners are loose you can remove the air box (plenum) from the inside and then the heater core comes out (from the inside), of course remove the supply and return hoses for the coolant too. Well that's about it. __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

January 22nd, 2007, 10:00 AM	#4 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	No problem! I don't have small hands and I end up with scratches all over the back of my hands. __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

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January 22nd, 2007, 08:04 AM	#3 (permalink)
Tim Burleson Junior Member Join Date: Jan 2007 Posts: 3	Thanks Oldsguy, I do have small hands and your information will be very helpful next weekend. This forum will be extremely helpful for me. Thanks for taking the time to advise me and do have a wonderful week. Tim

January 22nd, 2007, 07:36 PM	#5 (permalink)
Tim Burleson Junior Member Join Date: Jan 2007 Posts: 3	Question: Can I temporarily bypass the heater core by taking the supply coolant hose and routing it directly into the return without harming the engine? I need to use my delta 88 as a daily driver as I won't have time to change the heater core for several weeks. Thanks in advance Tim