just finished installing a 302 in my old falcon. I have a very small coolant leak behind the flywheel doesn't leak worse with the cooling system pressurized but will drip about a 1/4 cup of coolant overnight. there are no freeze plugs at the back of the block and I am sure its not coming from above (head gasket or intake) I am thinking there is porosity in the block or it may have a crack. that I didnt notice when I was putting the engine together. the engine looked to be new when I pulled it apart , I assumed it was from a low mileage wreck but now I am thinking it was pulled because of a problem with the block. the radiator and heater core are new. I am considering trying to seal this with stop leak and if that doesnt work I was going to pull the trans and pin the crack if that is what it is. I was leaning toward the GM pellet type sealer that they run in the some of aluminum caddy engines. seems that wouldnt plug up my new radiator or heater core. any thoughts? recomendations?
I have seen Bars stop leak used successfully many times. They used to advertise that some manufacturers put it in from the factory, or something like that. But many times on the ranch things would spring a leak and in went a bottle of Bars stop leak and most of the time the leak stopped and no overheat. But remember all stop leak stuff is designed to plug holes and your radiator has” holes” . Lol Bones
Blue devil head gasket sealer. Follow the directions to the letter and it should seal your leak. The cost is about $40 I did a Mitsubishi V6 2 years ago with it and is still holding.
We use the GM tablets with every engine that has head bolts or stud going into the water jacket. Toyota bought them all out once when their pickup engines started leaking.
Tried some sealer 20+ years back,called Block Seal,,It worked an amazed me some that it did,was still working when I sold the car over a year latter. I just looked it up again,so its still out there !; https://shop.advanceautoparts.com/p...1hyauVap4T6caqltBpRoCfW4QAvD_BwE&gclsrc=aw.ds
Around 10 or so years ago, International truck switched to an extended life coolant and their front cover gaskets were not designed for ELC. The factory “fix” was to install “cooling system sealer tablets”. These were the round brown tablets about an inch or so in diameter. The TSB that covered this “repair” said to use 20 tablets in trucks and 26 tablets in rear engine school buses. Bear in mind that the truck cooling system was 7-8 gallons depending on radiator. In all of these “repairs” that I administered, I never had a heater core clog up. After that, I figured that 4 or 6 tablets sure wouldn’t hurt a car or light truck. By all means, I would sure give the Bars Leak tablets a shot. Sent from my iPhone using The H.A.M.B. mobile app
I used Liquid sodium silicate also known as water glass from a drug store to seal a 3208 cat block that had pin holes in it worked good until it started to leak into one of the cylinders just put it in with water run until warmed up and drain leave sit with the drain plugs out over night then fill it up and your good to go. Sent from my iPhone using The H.A.M.B. mobile app
DIKE from Radiator Speciality Company. Won't stop up heater cores, but will usually stop leaks unless they are huge.
I have used this stuff, but its been years. It did work, for me,at least.I looked up the MSDS sheet on it and one of the ingredients is sodium silicate, aka Liquid Glass . Imagine that! I've used that too, and its a dang sight cheaper. YMMV. Good Luck
A black light should show where the coolant is leaking if it is an antifreeze mix. It would be good to know the location of the leak as the antifreeze would glow from the leak down. I think warm the engine up to temperature so the coolant develops pressure that may make the leak active. A crack might glow if it is wet with antifreeze or it may show the head gasket is the source. There should be a coolant trail below the leak. If the engine is really oily then it may need to be cleaned first as oil glows with a black light also and might interfere with the search.
An old trick used by old timers is liquid egg preservative. It works. May be hard to find these days, but it's still available. https://www.lehmans.com/product/water-glass-liquid-sodium-silicate/
Are you sure it's not the water pump or thermostat housing, running down the front then down the pan rail and dripping. Seen that before. Sent from my SM-G973U using The H.A.M.B. mobile app
Yep. K&W block seal is liquid glass with slivers of copper and such. I have seen it work many times but you do need to follow the directions. It is not an " Add it and Forget it" product" like Bars Leak. Moroso makes a ceramic sealer that I also had good luck with.
Am I the only one old enough to remember.... THE CONDENSER SYSTEM LEAK In 1958, the USS Nautilus, the world's first nuclear powered submarine, made its historic journey and ran into a major system failure which threatened the entire mission. ... After introducing Bar's Leaks into the condenser system of the USS Nautilus, the leak was stopped. "Bar's Leak" as my old auto repair shop partner used to tell customers, "it saved the Nautilus"
Sodium Silicate aka "Water Glass", as every schoolboy knows. Included in Gilbert Chemistry sets. "On June 3, 1958, the USS Nautilus, the world's first nuclear submarine, visited Everett and Seattle. In Seattle, crewmen dressed in civilian clothing were sent out to secretly buy 140 quarts of an automotive product containing sodium silicate (Bar's Stop Leak) to repair a leaking condenser system. The Nautilus was en route to the North Pole on a top secret mission to cross the North Pole submerged." Might have saved the Nautilus but water glass was also used to permanently disable millions of perfectly serviceable car and truck engines in the so-called "Cash For Clunkers Program". About 2 quarts poured in the crankcase trashes the bearings and locks it up. Hm.
I've use ground ginger root (one of the small cans out of the kitchen) with success going on several years. Quote from GM forum: "The GM coolant supplement pellets are made by the same company that markets the BarsLeak brand. The powdered BarsLeak gold is the same as the GM supplement. The BarsLeak in the jar with the brown liquid has the same material for sealant as the GM supplement but includes the soluable oil (brown liquid) to make it easier to pour in. The water pump does not need any sort of lubricant.... There are other sorts of sealers and brands on the market. I personally only recommend the conventional BarsLeak, BarsLeak Gold or the GM coolant supplement based on the extremely successful testing I have done in the past with those products. The ingredient in the coolant supplement is ground up ginger root and walnut shells. The fibers in the ginger root mat in a leak and swell when exposed to the air on the other side of the leak to seal it. The other sealers that use metallic components (such as BarsLeak Liquid Aluminum or the Solder Seal sealant) are definitely NOT recommended. The GM sealant and/or the BarsLeak brand is better because of the ability of the sealant to seal any coolant seepages without doing any other harm to the system. The main focus of the recommendation to use the supplement is to protect against any internal seepages that would put coolant into the oil and be invisible otherwise. The ground up ginger root has proven to be one of the best imaginable cooling system sealers through the process of elimination. It just works better than anything else currently known and is basically harmless to the cooling system otherwise. The use of cooling system sealers is widespread in the automotive industry and elsewhere. Most makers install the supplement at the factory. I have been told by reputable sources that even the cooling systems in nuclear submarines use the same "coolant supplement"
If you’re somewhat unsure about the source, add some dye, run the engine a while (I would think at least until the thermostat opens and closes a few times - in a daily driver I use it a few days), then examine the engine exterior with a black light. The leak(s) will jump out like a diamond in a goat’s ass. You can get the dye at NAPA, etc.
Solder Seal used to make a product called Block Saver. My brother used it to fix a cracked 327 block that froze up. It worked right away, we watched the crack stop leaking as it circulated. The crack was right by the fuel pump boss.
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