HOW TO: no driver side heat fixed, stop leak removal.

Hey guys. Just wanted to share a discovery I've found into the dreaded issue of having little/no heat on the drivers side.

So first, let me take you back to when this all started.

Shortly after buying my truck in late 2019, I replaced the weeping water pump, and knicked the radiator in the process. I figured, hmm, no biggie, I'll throw a cheap bottle of stop leak in it. I've used it many times in the past with great results on older vehicles (older vehicles had larger tubes in their heater cores, which is probably why I never had an issue)

So I get back home, take out my radiator, get it repaired and flushed at a great shop, and now we're rocking and rolling!.....except I have zero heat on the my drivers side.... I burp the system really well, but still no dice. I swap the heater hoses on the heater core, and now I have heat! I initially chalked this up to having air in the heater core, as I had heat on the passenger side. Oh how wrong I was.

Over time my driver heat got progressively worse, swapping hoses, flushing the heater core, burping the system, etc etc, nothing was working. I checked the blend doors and they were all good. I was getting around 90F at my far driver vent, 110F at the middle driver vent, 140-150F at both passenger vents with temp prove inserted all the way into vent.

I googled products that could dissolve stop leak safely in a heater core, but always came up short when finding and answer. It seemed no one knows how to dissolve it. Well, I found something that works, and works really great.

Krud Kutter Concentrated cleaner and degreaser.



I set up a heater core flushing system using a 1/2hp harbor freight pump I already had, 50ft of 5/8 heater hose I got on Amazon, 2 female water hose connectors, and a filter screen.

After flushing around 10 gal of water through the heater core and it ran clear for awhile, I hooked up my pump system, added 1 gal of krud kutter and 1 gal of hot water and let it run for awhile.




After awhile the water turned grey in color, and the screen had these black specs and white fibers all over it. This was the stop leak dissolving and getting caught on my filter.





After flushing for awhile, I reversed the hoses, ran it, reversed the hoses again, etc. I also zip tied my Milwaukee oscillating tool as close to the heater core pipes as possible and let it run on low for about a minute every time I swapped the hoses. I figured some agitation would help things out.



After about 2 hours total, maybe 1.5 hrs run time, I drained the bucket through a strainer with shop towels to catch any junk, then stuck the water hose in the bucket and kept the hose and pump both running until water ran clear.



The amount of gunk I got out of the heater core is pretty insane. All the brownish stuff is the fiber material that's in the stop leak, I'm surprised hose much there is.




I'm now getting 145-150F temps on driver vents and up to 160F on passenger vents. I hope this helps some else out there,

 

Nice write up..

 

Why does a dirty heater core cause to lose heat on just the driver side? I have the same issue.