Hi there,

I'm trying to see if it is possible to flush the heater core by disconnecting the pipes in the engine bay, rather than disassembling the interior and removing the core.

One of the connections is easy to reach, but the other (the connection to the aluminum pipe next to the fusebox and immediately under one of the braces is a PITA to reach. I'm pretty sure I'm missing a trick on how to reach and disconnect this hose. Has anyone managed to reach and disconnect the upper heater core hose in the engine bay, and if so, how?

 

Never heard anyone flushing the heater core on a X351 XJ?
Do you think something is blocked? It has not been reported before?
Can you add your car details as that helps figure out the problem.
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It is a 2016 XJL AWD in the US with 115k miles. Currently recovering from a lower coolant hose failure. I have cold air on the Left Hand (driver's) side, but hot air on the Right.
I noticed there were a few threads reporting that for earlier models as a potential electrical failure, i've tried the hard reset approach but that hasn't changed anything.
I originally assumed an airlock, but bleeding hasn't changed the situation either. The old coolant wasn't in the best of shape, so I thought I would try flushing.

The only other report I've seen on here of this issue was someone who needed to replace the Climate Control computer for a similar issue, so I'm hoping it's not that.

I'm open to any other ideas and suggestions though!

 

Engine size/type is needed as the diesels have different stuff. Do you have 2 zone or 4 zone heating? Most XJ's have 4 zone and that should not matter as the heater core is the same for both.
Can you check for codes using a dealer level tool like the SDD? You do have a AUX coolant pump and it may have an air bubble in it or not working.

Have you bled the system using the bleed valve?




Also from the manual;





Also there are a number of stepper motors or blend doors that can cause this. They all set codes as it's a complicated system. With your symptoms it points to a blend door problem rather than a heater core problem. If the heater core was blocked you should see less heat on both sides of the car. In the manual it states there are 13 stepper motors mounted to the heater/ac case controlling air flow and temperature!

Is the air flow the same on both sides? Long shot but have you looked at the pollen filter? That should not effect anything like this but might as well check it. Another long shot is as always these cars are very sensitive to voltage and battery condition.

I really think that there is a code set that you need to find otherwise there are too many possibilities.
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@clubairth1 Thank you! I had tried bleeding, but didn't have the procedure correct, so thank you for that.

I wasn't able to get it onto an SDD, but I was able to get the heater hoses off and gently flush it in reverse before performing a coolant flush. There was some gel that was pushed out in the flush, I think the coolant had been mixed with another type at some point in the past.

The first flush improved the situation (better heat from the mid drivers side vent, but not from the far left) so I did it one more time, and now have great and consistent heat all the way across.

There is one heater hose that is a pain to remove in the engine compartment, just forward of the bleed screw. I was able to get to it with a DEF hose disconnect tool, and remove it that way. Easy to push back on afterwards, just hard to remove.

Thank you for all your help.

M

 

Glad it was a simple and cheap fix!
Those are the best.

Not sure what a DEF hose disconnect tool is? I might have to get one to service hoses.
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I bought this set, but only needed the 1" one. The problem is you can't quite get to the push connector that is pressed up against the fuse box surround by hand. This tool helped slide along that wall, around the connector and apply pressure. Had to lay on top of the engine to get my hand in there. I'm sure there's an easier way, but I couldn't figure it out!

https://www.lislecorp.com/specialty-...disconnect-set