Before you replace your heater core - Read This!
#22
#24
![Default](/forum/images/icons/icon1.gif)
I've done a heater core, blend doors, and evaporator core, all on separate occasions, on my wife's '02 Grand Cherokee. Trust me that VW looks like a piece of cake. On the Jeep, the column has to come out too, the console, in order to get the dash and console out the seats need to come out too, battery, battery tray, accumulator, basically you need bare firewall on both the inside and engine bay sides. And I've done it 3 times.
If anyone's interested, I'm trading a 2002 Jeep Grand Cherokee Overland for a '08-'09 XJR, lots of new parts!
Anywhoo, is there a writeup of the heater core change anywhere? I'd likie to look into that one before I buy.
Thanks,
Darel
If anyone's interested, I'm trading a 2002 Jeep Grand Cherokee Overland for a '08-'09 XJR, lots of new parts!
Anywhoo, is there a writeup of the heater core change anywhere? I'd likie to look into that one before I buy.
Thanks,
Darel
#25
![Default](/forum/images/icons/icon1.gif)
Also check the the fuse. F8, 10A in the trunk fuse box near the battery.
![Before you replace your heater core - Read This!-rear-fuse-aux-pump.png](https://www.jaguarforums.com/forum/attachments/xj-xj6-xj8-xjr-x350-x358-28/101379d1480974461t-before-you-replace-your-heater-core-read-rear-fuse-aux-pump.png)
I checked the AUX pump for operation as the heat has been rather anemic.
This was even after a pump replacement. Turns out it did not even run at all. I checked the voltage and found it did not have 12V. According to the circuit diagram, it should run whenever the blowers are on. Seems the old pump wore down and the brushes shorted locked the armature or something and blew the fuse.
This was while pulling my leaky expansion tank due to cracked bleed hose, I also saw that a number of other hose assemblies were 'puffy'.
I elected to change the whole connection and hoses to the expansion tank
C2C19596
#14 below
![](http://jaguarpartsinternational.com/media/images/oe/collision/4/4725051.gif)
https://jaguarpartsinternational.com...gramCallOut=14
Seems that a few things start to get weak after 150k miles.
![Before you replace your heater core - Read This!-rear-fuse-aux-pump.png](https://www.jaguarforums.com/forum/attachments/xj-xj6-xj8-xjr-x350-x358-28/101379d1480974461t-before-you-replace-your-heater-core-read-rear-fuse-aux-pump.png)
I checked the AUX pump for operation as the heat has been rather anemic.
This was even after a pump replacement. Turns out it did not even run at all. I checked the voltage and found it did not have 12V. According to the circuit diagram, it should run whenever the blowers are on. Seems the old pump wore down and the brushes shorted locked the armature or something and blew the fuse.
This was while pulling my leaky expansion tank due to cracked bleed hose, I also saw that a number of other hose assemblies were 'puffy'.
I elected to change the whole connection and hoses to the expansion tank
C2C19596
#14 below
![](http://jaguarpartsinternational.com/media/images/oe/collision/4/4725051.gif)
https://jaguarpartsinternational.com...gramCallOut=14
Seems that a few things start to get weak after 150k miles.
#26
![Default](/forum/images/icons/icon1.gif)
Core was the size of a brick, mounted at the base of the windshield up against the firewall.
Pile of parts at the dealer took up 2 service bays (besides the one the car was in...).
#27
![Default](/forum/images/icons/icon1.gif)
So, 2004 XJR with 120K. Heat progressively goes away over the past few winters until it's cool this year. Not cold, mind you, but it just doesn't feel warm. If I put my hand in front of the air vents, it feels a little cooler than ambient, but as I stated, I'm not freezing to death when it's in the teens.
So, I keep reading all of these horror stories about clogged heater cores under the dash. ok. That must be the problem.
I got my indy to try to flush the cores. But that only worked for about the hour that it took to drive home. Next day back to the same.
Well, I picked up on those who were starting to explore the auxiliary water pump that is attached to the radiator. Well, that got me thinking. I can't tell you how many things I've replaced in the area of the radiator. All of the hoses, the expansion tank, repair to the windshield washer reservoir, etc. There is just so much heat up there.
So, on a whim I just decided to order the pump and replace it before verifying that the pump worked or not. After all, I can probably replace the thing in a couple of hours and I'm sure I'll have to replace it in the future anyway, so may as well be proactive.
Well damn if I don't have glorious, wonderful, melt your toes and face right off HEAT!!!!! Wow, I didn't think I'd ever get heat again.
So, give thought to replacing that little pump before you spend a lot of $$$ replacing the heater cores!
Mark - Ready for more Winter!
So, I keep reading all of these horror stories about clogged heater cores under the dash. ok. That must be the problem.
I got my indy to try to flush the cores. But that only worked for about the hour that it took to drive home. Next day back to the same.
Well, I picked up on those who were starting to explore the auxiliary water pump that is attached to the radiator. Well, that got me thinking. I can't tell you how many things I've replaced in the area of the radiator. All of the hoses, the expansion tank, repair to the windshield washer reservoir, etc. There is just so much heat up there.
So, on a whim I just decided to order the pump and replace it before verifying that the pump worked or not. After all, I can probably replace the thing in a couple of hours and I'm sure I'll have to replace it in the future anyway, so may as well be proactive.
Well damn if I don't have glorious, wonderful, melt your toes and face right off HEAT!!!!! Wow, I didn't think I'd ever get heat again.
So, give thought to replacing that little pump before you spend a lot of $$$ replacing the heater cores!
Mark - Ready for more Winter!
#28
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