Lessons Learned... or, how I discovered Bar's Stop Leak and what I used to fix the brand new heater core it clogged up.

I added a full gallon of Prestone which put him just barely above the full line and dropped in the tablets.
I used to have cars that needed bar's leak powder for whatever reason. Saturn s-series were one.

I'd take an old gatorade bottle, fill it mostly with 50/50 coolant, and the bars leak, and shake that up before pouring into a radiator with room for it to fit. Preferably with the motor running! That would suck it in and distribute it pretty well. If I'm unlucky to have a full system I drain an equivalent amount before working.

A lot of people put bars on top. It floats! This mostly clogs up the radiator cap and its valves and bypass hoses. The saturns used a surge tank that went into a heater/bypass hose, so if I could get the tank to be empty my evil concoction would immediately be swept up by the water pump and sent throughout the system.
Howdy ya'll, long time lurker, first time poster. Fair warning, I'm not new to forums and can be a little long-winded.

I figured I'd make my introductory post here by detailing my recent overheating debacle, the mistakes I made, and the fixes to all of my issues. The vehicle in question is a 2013 Ram 1500 with the 4.7L V8 motor.

So, I'm stationed in South Carolina and we were planning to visit family over the Christmas and New Years holiday. About 4 hours into the drive on December 19th, shortly after rapidly accelerating after a restroom break at a Love's truck stop, my dash started flashing an overheat warning. I got off at the next exit and stopped at an Autozone (first building off the ramp thankfully), stopped the truck, and promptly watched the overflow bottle boil over. After letting it cool down, I was able to get the rad cap off, top it off, and limp it down the highway to my inlaws' house. It was definitely only being air cooled for the last 1.5 hours of that drive. If I touched the gas, the temp shot up and if I was coasting the temp slowly dropped. The truck has a nice digital cooling readout in the dash, so I was able to observe the temp fluctuating between 225 and 250, however the overheat light never came back on so that tells me it was way hotter than that when I did get the overheat light.

After speaking to my mechanic uncle, I swapped the thermostat. Didn't fix anything. Swapped the water pump. Didn't fix anything. Now, let me pause to say that I'm generally very mechanically inclined. I've been an aircraft avionics technician for almost 14 years and digging into things like this doesn't phase me. That being said, my uncle had mentioned that I may have a blown head gasket and I decided to dump about 3/4 of a bottle of Bar's Head Gasket Repair into my radiator (without searching google beforehand). It was kind of a knee jerk reaction and a mistake. I'm sure most people here know this, but DO NOT USE THIS STUFF IN YOUR VEHICLE. Immediately, my overheating issue became exponentially worse and I couldn't drive the truck a half mile without the temp skyrocketing to 260 degrees and overheating.

At this point, we rented an 18 foot trailer and hauled my truck to an auto shop down the road. They tested the coolant and determined that I did not have a blown head gasket, thankfully. They diagnosed and extremely clogged radiator as well as a shot fan clutch. I agreed to their replacement solution (at 4pm on a Tuesday) and they called me at 10am the next morning saying my truck was fixed. Out the door price was $499.35 which included the coolant diagnostic, radiator, fan clutch, and labor. The caveat to this is that they said the heater core was extremely clogged up and there was little to no heat blowing.

I tried flushing the heater core out with vinegar and CLR, but neither worked. Ordered a heater core from Rock Auto and had it in two days. We actually had to drop the steering column, pull the entire dash, and evacuate the AC system to get the HVAC unit out in order to replace the heater core. After replacing it and re-assembling everything else, I was optimistic as I started getting warm air as the system started to come up to temp. However, after running the system a few times while trying to burp out air bubbles, it became apparent that residual Stop Leak crud was clogging up my brand new heater core.

Jump to a few days ago, back home in South Carolina, and I remember watching a video of a guy on YouTube swearing by a product by IronTite called Thoroflush to get Stop Leak out of your system. After driving 6 hours in 40-50 degree weather with no heat with a wife/baby on board, it was time to try something besides vinegar and CLR. During this whole process I also discovered the auto shop put universal green coolant in, so that was in the plan to swap out as well.

I started by draining the radiator completely. I then installed a flush kit on the heater inlet hose and flushed the whole system for nearly 10 minutes, until the water flowing out was completely clear. I then removed the thermostat (which was caked up with all sorts of stop leak fibers) and reinstalled the housing. Filled the system with water again, then followed the instructions on the bottle of Thoroflush. Drain a gallon of fluid from the radiator, mix the thoroflush with a gallon of warm water, shake well to dissolve the crystals, then pour into radiator. If you don't have spill-free funnel at this point, get one! Absolutely the best thing ever made for burping a coolant system. Anyways, after the truck got up to temp, I set a 12 minute timer, revved the motor several times to circulate the product, then turn off the truck at the 12 minute mark. After letting it cool down, I drained the entire system and flushed absolutely everything for several minutes with a garden hose, then blew out as much hose water as I could with low pressure air. You would not believe the amount of crap that came out of this thing. It looked like someone dumped a few cups of beach sand into the system. Thoroflush did its job for sure. After priming the water pump and heater core, then filling the radiator and reservoir with fresh, up to spec (MS-12106) coolant, my heat has never blown hotter and the truck has never ran cooler. My average temp after a few days of driving in 50 degree weather is around 200 degrees and my heat is blowing nearly 150!

I mainly made this post to help out others. After doing a few google searches, there really isn't much documentation on how well Thoroflush works so I wanted to help our those search results for folks that have clogged up radiators and heater cores or for those wanting to rid your system of Stop Leak products. For around $20 and a few hours of my time, my truck is running great!

- Matt
Back in the late 1950's, it was discovered that the USS Nautilus SSN-571 had a water leak in one of it's systems. The leak was fixed , apparently permanently for the whole time it was commissioned, by using a number of bottles of some variety of Bar's Stop Leak that was readily available at the time.
Marshfield , MA
When BMW built the E 28, the first piece down the assembly line was the HVAC unit. The rest of the body interior was added then the windshield. Then the entire body was lowered onto engine/trans sub assembly. My son's college beater '86 528e developed a heater core leak. About once a yr I added a 1/2 bottle of the Bars Leak and a little anti freeze. :cool:

Part2. When I was getting a totalled '88 528e back on the road, I drained and then flushed the terrible looking brown sludgy coolant out of the system . After I pressurized the system I did a visual. There were a good 2 dozen pin holes in the aluminum core, It was hilarious. The brown sludge must have been good ol' Bars Leak. I had 2 spare radiators. So no big deal
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Yep my dad used to swear by that sealer stuff for the cooling system and head gaskets and everything then we realized how bad it was and never used it again. And never will. And being made by a reputable company we thought for sure it was good stuff wrong. At least you know now and hope you will tell others too.
One thing rather odd is Ford and GM have their own stop leak tablets they use at the factory ostensibly because their cooling system parts all come from different vendors. Supposedly these tablets work great and don't clog stuff. My mom's Five Hundred looked to have some sort of stop leak in it when she got it from the dealer, and lo and behold 100K miles later it's been fine and never overheated or clogged a heater core, etc, so I'm guessing it's the factory stop leak tablets.

These are the GM ones, but Ford has similar looking Motorcraft branded ones.

I don't quite know what to make of this subject, just saying it exists and is a thing.
I had a Chevy Venture with a head gasket that was failing. I used the stuff pictured, HG sealer, and it seemed to work. Two days later the whole thing blew and the van was donated to the Salvation Army. I've never decided if it helped or hurt.
Cedar City Utah
These are Bars' Leaks Tablets made for manufacturers and used by a multitude of car companies. They have been used for many years and are the same you can buy in the blister packs.
So in summary, there is no headgasket leak and OP put headgasket leak sealer?
The sealer clogged something that was originally clogged anyways.
Now, OP said sealer does not work?????

Question is, is there a leak or a clogged?
If it is a clogged why you add sealer?
A de-clogger should be added instead? if there is such a product.

I am trying to understand the logic???

IMO, OP should blame the vehicle manufacturer's part quality and manufacturer for using parts that breaks.
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Had good luck with the Copper sealer, had a rough running engine and losing water but nothing in the oil, figured it had to be a head/intake gasket leak, did a radiator/engine flush and put a bottle in with a gallon of anti freeze and topped off the water. So far so good, cleared up in a couple of days.