In part one we started our discussion of additives with those for the fuel system. Considering Paul’s recent post on his Subaru passing the 150K mark and comments about the tendency of head gasket issues, I figured cooling system additives would be a good place to go next.
Cooling system additives also come in a number of basic flavors.
Flush: These are intended to be used before installing new antifreeze. Most of the products on the shelf in this category, at least in the US, are pretty mild and won’t have much affect on a really dirty system. It you live somewhere that you can still get flushing products that come in two bottles the flush and the neutralizer they are usually the strongest and might clean up that system that hasn’t been changed in say 15 years. However if there really is that much corrosion in the system that might be the only thing holding stuff together so just like power flushing consider the risk before you go with the more vigorous chemicals or methods.
Or you can try some household products to clean your cooling system.
Anti-rust and water pump lube: These are often times sold as a combo product. The anti-rust is either something that will neutralize existing rust or just some sort of oil that the tout as lubricating the water pump. The thing is that the bearings in a water pump or sealed from the liquid side of the pump, so at most they could lubricate the seal. The problem with the products containing oil is that cooling system hoses are not designed for use with oils.
I personally use a product on one of my wife’s cars. The cooling system was pretty neglected when we bought it so after flushing, replacing the thermostat and hoses I added some anti-rust/water pump lube. Within a few weeks I was replacing those hoses again as they were now very soft from the oil in that product. On some late model cars that have a rubber seal in the valve of the thermostat could experience problems. So I shy away from these products completely now.
Water wetter/super coolant: These products claim to make your car run up to xx degrees cooler. They work on the principle that if you reduce the surface tension of the coolant it can transfer heat better. However many of those products say they recommend using it with pure to no less than 60% water. The dirty little secret is that ethylene glycol is not that good at transferring heat, water is actually better. For example I have seen in Ford owner’s manuals where they state that while 50/50 is the normal recommended ratio for exceptionally cold climates 40% water 60% antifreeze can be used and in particularly hot weather or high load situations to use 60% water and 40% antifreeze. For the most part these additives are more band-aids than anything else. If you need one of these products your cooling system is not up to snuff. The system may be partially plugged due to neglect, you are exceeding the designed rating of the vehicle or you’ve upped the power level of the engine without a corresponding increase in cooling capacity.
Stop leak/sealer/coolant “conditioner: Often times you’ll hear people state that these will plug up your radiator or heater core. Some of them seem to be more prone to that than others. Many times it is the overall neglect of the system that resulted in the leaks is also the likely reason the blockage started. I also believe the different types of sealers are more or less prone to cause problems. Ones that seem to work on the same principle as adding black pepper to the system, particles that are large enough to act as the finger in the dyke will often do the trick on small leaks in gaskets, radiators, and heater cores. They aren’t very effective in sealing water pump and leaks to the combustion chamber. Often times these come as a powder, tablet or a liquid with a fine powder floating in it.
GM recommends their “coolant conditioner” tablets be added at each coolant change for many of the Cadillac and some other engines. Subaru recommends their “conditioner” with each coolant change for a number of their engines. The one in Paul’s is an example. Some of the Subaru head gasket failures are external leaks. In my research I came across this info on the Scooby Enthusiast forum that the the active ingredient in the Genuine Subaru conditioner is linseed meal. That’s the chunks on the paper towel. In addition there are some of the same corrosion preventives as used in regular antifreeze. So it is likely that Paul’s Subaru received a dose with fresh coolant when its water pump was replaced.
Send your questions or requests to curbsideclueless@gmail.com
Yes, Subaru had us come in to put in their proprietary leak-stop product early on. And I do hope my mechanic added some more when he did the water pump at 100k miles.
The problem with the Subaru stuff is that it not only does it have “chunks” in it, it’s the color of rust. So is it there stop leak in there or is the cooling system just rusty?
Funny you mention it. When our Subaru head gasket starting leaking the first time, the dealer put in their special coolant conditioner. That seemed to last until the extended warranty expired. I’m wondering if the dealer should’ve just replaced the head gasket in the first place. Does anyone know if you have to keep using the conditioner even after replacing the head gaskets?
It doesn’t seem to plug heater cores or radiators so I’d consider it cheap insurance.
Leaking radiator or heater core Pepper fix works. Ive used this method many times no good on leaking headgaskets but on radiators just run the engine with rad cap loose for while then under pressure when leaking abates.
I don’t think Water Wetter was originally designed to be used in daily drivers. When it was introduced it was marketed mainly at racers.
I’ve found it works very much as promised at the track. Our car had a restrictor in place of the T-stat and an electric water pump, the WW would allow us to drop 15* to 20* between rounds much quicker than straight water.
After using some stop-leak product that didn’t fix the radiator leak but did insure that I would never again get any heat out of the heater, I decided that ethylene glycol is the only cooling system additive to use.
A 1962 Lincoln I once owned turned out to have been driven for a long time with plain water in the cooling system because of a niggling radiator leak. That car had two heater cores that were mounted way back in the fender wells somewhere, and we ended up doing a great many partial flushes to get most of the rust out of the system. Then we refilled it with half-water, half-antifreeze, and didn’t have any more problems.
I had an 84 GMC van that developed a rad leak at the seam in one of the end tanks. I was already considering replacing the van by the time this happened, and that helped my decision. I threw in a can of Barr’s Stop Leak. That kept the rad sealed enough to keep it in check while I looked for a replacement vehicle. I bought my pickup in late 2000, then kept the van around as a beater to drive to work through that winter. I would be very hesitant to use a stop-leak product on a vehicle I intended to keep though.
I had cooling system issues in one of my 1966 Chryslers after swapping-in a much upgraded engine. Temp would climb when idling or driving around town. Tried Water Wetter. No or marginal improvement. After years of trying different things, finally determined that the Edelbrock-style “scroll vane” water pump impeller design is NFG. I installed a Moroso high flow pump and thermostat and have not had any more problems.
Another coolant additive specific to diesels that was not mentioned is Supplemental Coolant Additive (SCA) which deposits a sacrificial coating on the cylinder liners. In a nutshell, the sharp “crack” from diesel ignition can cause microscopic bubbles to form in the coolant on the surface of the cylinder liners. These cause cavitation of the liners, eventually leading to engine failure. The SCA coating gets worn away instead of the cylinder wall itself.
Yup, SCA is a must for any wet cylinder diesel engine. Water wetter like products help as well because they limit cavitation. There is a commercial truck equivalent available as well as low foam, low silicate coolants.
I remember a relative telling me to put oatmeal in a leaky radiator just before trade in. Any thoughts on that strategy and the efficacy of the fix?
I have heard the oatmeal thing too, but I had assumed that this stopped being recommended by, say, WWII. But in a Model T, go for it!.
Steel cut Scottish Oats are the way to go. And if it has a noisy rear end, some sawdust will do the trick! Smoky engine, put synthetic in it. Noisy lifter, slight rod knock, put lots of Risolene (thick oil stuff) in it. Squeaking belt, dish soap. Dull faded plastic parts, mineral oil them. Scuffed tires, Wesley’s Blech White.
All of these are of course used car dealer tricks, don’t attempt if honest!
Bri nylon shirt in a cures a noisy gearbox but not recomended.if its your car.
Never heard of oatmeal for stopping a radiator leak, but I have heard of using an egg.
Over the weekend, my son Jimmy and I were up to our elbows in an 89 Grand Marquis replacing a lot of old hoses. (They all said Motorcraft. What do you suppose that means?)
Anyhow, on one of our trips to the parts store (thank you, automatic temperature control) I saw a display for AlumaSeal that took me back to the 70s. My friend Lowell poured some into the leaking radiator of his 68 Cougar. I don’t think he was happy with the result. I think that this stuff was like the pepper fix, but with some sort of metallic particles that were supposed to sort of solder the hole from the inside.
I cannot remember if the leak was too big for it to handle, or if something else got plugged up. What I do remember is coming away from the experience with a bias for just fixing the stupid leak rather than pouring something into the radiator.
That stuff always works for me
I don’t remember the brand name, but I remember the same mixture. Fine aluminum particles suspended in some sort of goo. Different brand name; Stop-Leaq or something like that.
It worked, for a short time. Also, it plugged up the heater core. Never again, I swore, for such a cheap-a$$ fix.
Motorcraft genuine Ford parts a good sign.
I think what he means, Bryce mate, is that it was original equipment…22 years after build.
Meaning, nobody bothered to replace the rubber. Old-man preservation, what?
Nothing blew either so i guess thats a good sign.
You have it. Either original equipment from 1989 or replaced by a Ford dealer service department, still a long time ago. Either one is a good sign. I am not good enough with Motorcraft logos to date these, but I know that this kind of rubber stuff will last a long time with gentle use.
In the late 80s, I bought a 20K mile 1966 Plymouth Fury III. All of the belts and hoses were stamped with the obsolete PDDC logo (for Plymouth Dodge DeSoto Chrysler), not the more modern Mopar pentastar logo, so I KNEW how old those were. They came off immediately.
The rad hoses on my dad’s 66 are probably STILL original. He doesn’t replace anything unless it looks like it will fail imminently. Of course, I only recall changing an upper rad hose on one of my cars; the rest are of unknown vintage.
A lot of the Ford hoses do have the MM DD YY on them but it is often stretched out so it doesn’t always look like a date.
My used car mentor Nate, used to rave about something called Barsleak, which, IIRC, had ground up cork in it.
Click and Clack speak highly of Barrs Leak
Not exactly an additive, but a friend who’s a chemist & mechanical engineer recommends using distilled water instead of tap water in the coolant mix. For us, we not only get the usual lime deposits, but also iron and sulfates (somewhat volcanic area–I like the water taste, YMMV.) As a result, we get deposits best removed with gunpowder or C4. So, at coolant change time, it’s a trip to the water section of the store.
He’s kept some rather old pickups running, so I think it’s worth it. Cheaper than flush. (Distilled water is about 0.80 to $0.90 a gallon so far.)
I would not use tap water in a rad or to top-up a car battery. Distilled or deionized water are the best. I have a dehumidifier running in our basement, and I have used the water collected from that. I figured that there will be a small amount of impurities from the dust in the air, but it’s basically distilled water. I bought a jug of water last time I needed some though. A jug of deionized water is cheap, so it’s probably not worth taking chances unless you’re in a bind.
I’ve used Barrs Stop leak on my 87 nissan pickup, after getting in to a front end accident. not the proudest moment of my life but it still works, I also pinched the line a little (it was a big leak) was my daily driver until i got the bus two weeks ago been about 6 months and ran a good 400 miles the day I put it in. (family and I were going on a trip about a week after my accident when the leak got big enough to notice,I was wondering why I kept getting water drops on my windshield Doh!!!
You skipped over another family of coolant additives, the “instant head gasket repair” products, such as K&W Block Sealer. The active ingredient in these products is sodium sliicate, better known by its trade names of liquid glass or water glass. They also usually will have some copper particles in the solution. It is the liquid glass that makes the seal, not the copper. And it will seal just about anything. The problem is, when liquid glass meets ethylene glycol, it transforms into a substance not far removed from concrete. Most people do not flush the system out before adding liquid glass, then don’t flush out the liquid glass before refilling the system with antifreeze. I’ve seen radiators and heater cores in our radiator repair shop just blocked solid with liquid glass. Not good.