Drivers Side No Heat - Fixed

Hey Guys,

I managed to get the dreaded Driver Side No Heat issue on my LHD 2005 LR-3.

The issue coincided with a cooling system failure (cracked coolant manifold) and a dead battery, so naturally I started chasing a potential air bubble in the system to no avail, and then possibly blend door motor failure. After that I gave the system a good flushing with CLR and a large fish tank pump and bucket. Felt like it might have improved a bit, but couldn’t be certain.

What was so damn puzzling was that the passenger side was roasting hot through this whole experience, which really added to the confusion.

So anyway, having explored the air lock, flushing the core, and the blend motor (which was found to be working), in my mind the only option remaining was the heater core itself.

I won’t go into the details on how to remove it, but it wasn’t terrible, and frankly if it was warmer than -15*c outside, it would have almost been an easy job really.

Anyway, with the heater core removed I set out to try and see what the issue was.

Using the same fish tank pump (its big from Amazon), some CLR, heater hose and a bucket I went ahead and did a bench test of sorts. I filled the laundry tub around the bucket with hot water to keep the process warm.



Low and behold, the end closest to the passenger side was getting nice and warm, but the other end was cold. Did the back of the hand test. It was literally at the 3/4 point is where you could feel the temperature drop off. This explains why the vent closest to the drivers window was occasionally lukewarm, but the vent closest to the radio and the footwell were always freezing cold.



I’m going to leave it with the CLR pumping through it to see if it will eventually unclog itself, but if not, its time for a new heater core.

So, when in doubt, this may be your only option to get heat back.

So, four hours of the CLR flush, followed by another hour of Castrol Super Clean and this sucker is working like new.

Actually boiled up a *** of water and ran it through with the pump and a fan blowing over the core as a test. Could burn your hand on each passage. Perfect.

In retrospect the $200 in parts may have been easier, but it was satisfying to fix this with items on hand at home.

forgive my ignorance . . .

could this flush be performed without removing the heater core?
by accessing the correct in/out pipes from underneath or in the engine bay?

douglastic said:

forgive my ignorance . . .

could this flush be performed without removing the heater core?
by accessing the correct in/out pipes from underneath or in the engine bay?

Click to expand...

I tried the CLR flush via the engine bay, but it wasn’t effective. Given that the heater core is so low in the system with hoses that go up and out the firewall, it seems like a logical place for debris to settle. I’d definitely give the engine bay route a go first mind you.

Not mentioned in my original post, I also ended up using a bottle brush in both openings to free up gunk and then changed the orientation of the core during the process.

Went for a long drive tonight. I forgot how powerful the heater was when this was new. It was clearly slowly getting gunked up before the manifold failure. Really pleased with it now.

armybuck04101 said:

Hey Guys,

I managed to get the dreaded Driver Side No Heat issue on my LHD 2005 LR-3.

The issue coincided with a cooling system failure (cracked coolant manifold) and a dead battery, so naturally I started chasing a potential air bubble in the system to no avail, and then possibly blend door motor failure. After that I gave the system a good flushing with CLR and a large fish tank pump and bucket. Felt like it might have improved a bit, but couldn’t be certain.

What was so damn puzzling was that the passenger side was roasting hot through this whole experience, which really added to the confusion.

So anyway, having explored the air lock, flushing the core, and the blend motor (which was found to be working), in my mind the only option remaining was the heater core itself.

I won’t go into the details on how to remove it, but it wasn’t terrible, and frankly if it was warmer than -15*c outside, it would have almost been an easy job really.

Anyway, with the heater core removed I set out to try and see what the issue was.

Using the same fish tank pump (its big from Amazon), some CLR, heater hose and a bucket I went ahead and did a bench test of sorts. I filled the laundry tub around the bucket with hot water to keep the process warm.

Low and behold, the end closest to the passenger side was getting nice and warm, but the other end was cold. Did the back of the hand test. It was literally at the 3/4 point is where you could feel the temperature drop off. This explains why the vent closest to the drivers window was occasionally lukewarm, but the vent closest to the radio and the footwell were always freezing cold.

I’m going to leave it with the CLR pumping through it to see if it will eventually unclog itself, but if not, its time for a new heater core.

So, when in doubt, this may be your only option to get heat back.

Click to expand...

Am I seeing an Engineers ring in the pictures?

I wear something on my little finger that looks similar and is rather worn as well.

It has occurred to me that probably all our older 3's are suffering the clogging problem to some degree.

This year, I have been wondering if my heater is a good as it once seemed to be? Unless one side gets full cold, it is a slow process that over the years, one would not notice.

I have replaced the heater fan and that "resistor" and while doable, did not find it a particularly enjoyable task - did it in the summer rather than the middle of winter so laying on ones back was more of a sunburn concern than frost bite.

I assume to pull the heater core, it is much same, all done from the passenger side - remove the fan and keep tearing stuff out and then mop up the spilled antifreeze?

I do compliment you on your success as this is the first time I have seen a post that ended with other than replacing the heater core or giving up.

bbyer said:

It has occurred to me that probably all our older 3's are suffering the clogging problem to some degree.

This year, I have been wondering if my heater is a good as it once seemed to be? Unless one side gets full cold, it is a slow process that over the years, one would not notice.

I have replaced the heater fan and that "resistor" and while doable, did not find it a particularly enjoyable task - did it in the summer rather than the middle of winter so laying on ones back was more of a sunburn concern than frost bite.

I assume to pull the heater core, it is much same, all done from the passenger side - remove the fan and keep tearing stuff out and then mop up the spilled antifreeze?

I do compliment you on your success as this is the first time I have seen a post that ended with other than replacing the heater core or giving up.

Click to expand...

I think part of the problem with flushing this from the engine bay is because gravity is preventing debris from getting lifted out, and the heater core being down low like it is, is a natural place for gunk to want to settle in the system.

I can see why the blend motors is a natural place to want to lay blame, as in my case there was literally no heat on the drivers side, and plenty on the passenger side. So I went through the whole process of removing the drivers blend motor and testing it. Once I saw that the motor was working and the door itself moved freely by hand, there was really only the core to blame.

The removal of the heater core really only requires taking out the complete glove box and pulling back on the trim panel which is above the carpet along the footwell. No need to touch the fan. If I had to do this a second time, far less things would have been removed, as panels and other items can be contorted enough in situ to allow for the removal of the heater core. Reconnecting the hard lines is the biggest pain. There are examples of guys cutting off the machined ends of the lines and just using rubber and hose clamps. I can see the appeal of this approach.

I’m happy it all worked out.

nicely done...now one more thing on my list to do before its an issue. Thanks for posting this up

armybuck04101 said:

I won’t go into the details on how to remove it, but it wasn’t terrible, and frankly if it was warmer than -15*c outside, it would have almost been an easy job really. Anyway, with the heater core removed I set out to try and see what the issue was.

Click to expand...

PLEASE DO! (beers on me!)

I did the CLR flush last year and it only worked for a couple of months, now back to nothing...

I'd rather pop in a new one if it's "not terrible".

Hi maxx4wd,

I'm trying to short cut the heater core replacement - did you cut the plastics here to peel back the side panel for access or ? Also, I'm thinking to leave the pipes from core to bulkhead or any tips for that?

Stewart