04 Tahoe rear heater core

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Philthadelphia

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Jan 2, 2024
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Hey, short time reader and first time poster!

Bought an 04 Tahoe LS, 5.3l V8 recently. Plan was to not put any money into it since I barely paid anything for it and just drive it until it dies...but she's still pretty, runs amazingly well at 207k~ (163k~ according to my sister before the cluster went and was swapped with an escalade's) and I fell in love already, so I'm at least working on getting the creature comforts working again.

Got all the front HVAC issues sorted with actuator replacements and have since moved onto figuring out the rear heat issues (only blows cold) and discovered the rear heater core has been bypassed and the coolant line above the exhaust is now looped.

Unfortunately I can't contact the first owner about why this was done, but I'm assuming it's because it was leaking inside the trunk due to the carpet stains and clear signs of fluid when I took off all the passenger trunk trim pieces around it to replace that actuator, so I'm probably looking at a full replacement.

Looking for some advice from those who've done this repair/replacement before as far as how feasible it is, pitfalls I may run into, am I going to end up shooting myself in the foot trying to do it myself, etc...since I haven't really had much luck finding a thorough write-up or video about the process.

Any and all advice and information is greatly appreciated!
 

ivin74

05 NBS Nali
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Aug 3, 2014
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Htown, Texas
Hey, short time reader and first time poster!

Bought an 04 Tahoe LS, 5.3l V8 recently. Plan was to not put any money into it since I barely paid anything for it and just drive it until it dies...but she's still pretty, runs amazingly well at 207k~ (163k~ according to my sister before the cluster went and was swapped with an escalade's) and I fell in love already, so I'm at least working on getting the creature comforts working again.

Got all the front HVAC issues sorted with actuator replacements and have since moved onto figuring out the rear heat issues (only blows cold) and discovered the rear heater core has been bypassed and the coolant line above the exhaust is now looped.

Unfortunately I can't contact the first owner about why this was done, but I'm assuming it's because it was leaking inside the trunk due to the carpet stains and clear signs of fluid when I took off all the passenger trunk trim pieces around it to replace that actuator, so I'm probably looking at a full replacement.

Looking for some advice from those who've done this repair/replacement before as far as how feasible it is, pitfalls I may run into, am I going to end up shooting myself in the foot trying to do it myself, etc...since I haven't really had much luck finding a thorough write-up or video about the process.

Any and all advice and information is greatly appreciated!
How often do you have folks ride in the back? I hardly use the rear heater, the front heater heats up the suv pretty good reckon I hardly ever have anyone ride back there.

If you end up replacing the heater please do a write up. This might help someone having the same issue you are experiencing.
 

89Suburban

Bull in the china shop
Supporting Member
Joined
Jan 10, 2013
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Location
SE PA
Hey, short time reader and first time poster!

Bought an 04 Tahoe LS, 5.3l V8 recently. Plan was to not put any money into it since I barely paid anything for it and just drive it until it dies...but she's still pretty, runs amazingly well at 207k~ (163k~ according to my sister before the cluster went and was swapped with an escalade's) and I fell in love already, so I'm at least working on getting the creature comforts working again.

Got all the front HVAC issues sorted with actuator replacements and have since moved onto figuring out the rear heat issues (only blows cold) and discovered the rear heater core has been bypassed and the coolant line above the exhaust is now looped.

Unfortunately I can't contact the first owner about why this was done, but I'm assuming it's because it was leaking inside the trunk due to the carpet stains and clear signs of fluid when I took off all the passenger trunk trim pieces around it to replace that actuator, so I'm probably looking at a full replacement.

Looking for some advice from those who've done this repair/replacement before as far as how feasible it is, pitfalls I may run into, am I going to end up shooting myself in the foot trying to do it myself, etc...since I haven't really had much luck finding a thorough write-up or video about the process.

Any and all advice and information is greatly appreciated!
Love your screen name. I am up by Valley Forge. Any pics of the old girl? Rear heater core sounds like an interesting tinkering project. Maybe you can pressure test it somehow with plain water and compressed air?
 

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