No heat on driver side after adding Bar's Leaks to coolant

[M5Z3M]

My 2012 LR4 HSE Luxury (140,000 miles) has been emitting the smell of coolant for a while and now needs topping up every couple of weeks. Today I put 24 oz of Bar's Leaks into the coolant expansion tank and drove the vehicle for a couple of hours with the heat and the fan on high. The driver-side vents briefly (couple of minutes) blew tepid air a couple of times but for almost all the drive they were blowing cold air. The passenger-side vents were blowing hot air the whole time. The temperature outside was 14 degrees F.
Does the LR4 have separate heater cores for the driver and passenger?
Thanks for any insights.

 

[mm3846]

Nope just one. You clogged the heater core, it is angled a little so crud sits on the bottom/driver side. Stop leak should only be used as a last resort.

 

[Mozambique]

Errrrrr you might want to find the source of the leak if its leaking that badly?
Water pump? Crossover pipes?

 

[M5Z3M]

Thanks for your input.
Figured. It seemed unlikely that the blender flap failed at the exact same time Bar's was added. Any chance that continued use will clear the heater core or does it need flushing?

 

[Rover Range]

You can remove the heater core coolant pipes and flush the core out with a water hose.
You may have an air pocket in the heater core.

 

[ktm525]

Ouch. Never, ever use leak stopper in a modern cooling system. Hopefully it's a bubble but Likely the core is *****.

 

[M5Z3M]

My local mechanic says that replacing the core would involve removing pretty much everything you look at while seated in the front--a week's work. He suggests we first flush the heater core with sulphuric acid to try to expel the Bar's Leaks.
What is the original-equipment heater core made of? Brass? Copper? Aluminum? The non-OEM replacements I've seen in photos appear to be aluminum.

 

[mm3846]

You can remove the heater core without pulling everything, and stripping the dash down is pretty fast.

Google it, you’ll see where you can trim an access hole in the plastic to get to it, there’s posts on this forum and IIRC it’s aluminum.

 

[greiswig]

Sulfuric acid would (IIRC) be a very bad idea. It reacts with aluminum.

If it were me, I'd try disconnecting the hoses to the heater core, opening up the heater valve all the way, and back-flushing the heater core with a hose with variable pressure. The core ought to be good up to 14psi or so. This might keep you from having to pull the core out, and if it doesn't work you're already part-way into the R&R.

And I'd flush the rest of the system well, too; there's still stop leak floating around in there looking for things to clog up. Hopefully it's clogged the thing it needs to already.

 

[M5Z3M]

Thanks to all for the input. I should have mentioned that my mechanic ranked sulphuric acid as a third option and a highly risky one for the reasons stated above. If the acid were to eat through the aluminum, the problem would have mushroomed into something much larger. In the end, a careful flushing with water in alternating directions has cleared the blockage and heat has been restored to all outlets on the driver's side. CLR had been the mechanic's second option, but neither CLR nor acid was needed.
I got lucky, for sure. I knew it was inadvisable when I put the darned stuff in but took false comfort in all the label statements saying it was safe for all engines. Lesson learned.