Engine Block Sealer Additive Advice for Blown Head Gasket
Reader Question
Dear Austin, I saw your answer to someone below
after searching for a good block sealer: “If they DO suspect a blown head gasket or cracked block you might want to try a can of K&W Engine Block Seal additive you can buy at your local auto supply. Drain out the coolant, add the can of
additive to your radiator and drive the car for about 500 miles, then drain out the water/additive and install the proper mix of coolant and water to the radiator.
I have had great success with this method. WARNING – there will be NO freeze or overheating protecting during this time, since there is no coolant in the radiator.
” I have been having symptoms of a blown head gasket , getting white smoke from the tailpipe, smells like anti-freeze, boiling overflow bottle that has a gas or oil smell.
I have used “KW Block Sealer” (problem came back) then, “Cargo Seal-Up” both and still the problem came back. What caught my eye was you mentioned leaving the sealer in the vehicle and driving 500 miles.
I have followed the manufacturers instructions on both products by letting the vehicle cool and then re-filling
> with new anti-freeze. Maybe I should do as you have done and run the vehicle with the (sealer and water only mix) for 500 miles? Will it run that much more hot do you think? (I live in central Florida).
Any help would be appreciate, as I am not wanting to junk the vehicle but cant keep using these sealers and have them fail either. Thanks much for any suggestions, Matt
Hey there Matt
I have had great success using the K&W block sealer as I mentioned, but not as the manufacturer suggests. You should
be fine for 500 miles living in Florida. Keep me posted as to what happens. MAKE SURE YOU DRAIN ALL COOLANT FROM THE SYSTEM FIRST.
1. Product name is K&W Engine Block Sealer (available at auto parts stores everywhere)
2. Remove ALL coolant from the radiator and engine
3. Add can of sealer to radiator and top off with water only
4. Drive vehicle for at least 500 miles
5. Drain out sealer and water mixture and install proper coolant and water mix to radiator
YOU WILL NOT HAVE FREEZE OR BOIL OVER (overheating) PROTECTION DURING THIS 500 MILES!!!
Park vehicle in a warm garage at night during freezing temperatures and watch your temperature gauge in summer months at idle.
Reader update
Just a quick note Austin to say thank you again. The 1995 Ford Escort is working fine after leaving the KW Blocksealer in for 1000 miles. I then drained and flushed and filled with 50/50 anti-freeze.
Will keep ya posted!
Blessings to you for all your help,
Matt
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alright so i have a question. if i use this leak sealent and i DONT have a head gasket leak will it do any damage to my car? and also what should i do to keep my car warm at night so it doesnt freeze? i dont have a garage and theres no parking garage around?
No it will not hurt your engine if you dont have a head gasket leak BUT you are going to drain out this additive after 500 miles and then use the proper anti freeze water mixture again. You can place a 75 watt light bulb under the hood of the car to keep the engine warm. Its not failsafe but it will keep things warm under the hood. You can also remove the radiator cap, so if the water in the radiator does freeze it has a place to escape.
Hi, While trying to find the source of a new ‘ticking’ noise in the GM Bedford 330 marine Detroit Diesel installed in my sailboat, I discovered that at the rear of the engine, in the area of the head gasket, ‘puffs of air’ were being expelled from the engine along with a microscopic amount of oil. There is no sign of water in the oil or vice-versa, the engine is not losing coolant or oil, there is no sign of white smoke from the exhaust and the engine seems to be running ok. However, I cannot imagine how the air can escape if the head gasket or block are not cracked, unless the bolts holding the head down have loosened.
2 years ago the engine did seriously overheat when one of the oil cooler pipes ruptured without warning, pumping all the oil out within seconds, but has since run ok. Also, I have had vibration at times due to slight misalignment, which has now been rectified.
What does this sound like to you, please, because I am baffled. If it is the head gasket, head or block and I decide to use the Sealer additive, I’m worried about the water pump bearings because the ‘antifreeze’ in the coolant serves as a lubricant for them. Also, I would probably take 12 months to cover 500 miles under engine – can you advise on engine hours rather than mileage?
Any advice will be greatly appreciated.
I am not sure if the block sealer can be used with a diesel engine, probably not. I would seek a professional diesel mechanic for this issue….I am not one.
I have 2 questions about doing the K &W block sealer. One is: Do I need to remove the thermostat? The other is: How is driving for 500 miles making it work better than it should? I guess I’m concerned about leaving that stuff in the cooling system for that long.
No, leave the thermostat in place. Driving for 500 miles (in total….not consistently) allows the copper flakes in the additive to locate the leak and seal it. The additive will not adhere to antifreeze, so that is why you have to drain the system and install just water with the additive.
Thanks for the quick response. I’m almost ready to try this. One more thing. I’ve read how some of these products can clog the system…specifically radiators & heater cores. (I think that’s primarily the stuff that mixes with anti freeze and I understand how THAT could clog the system). However, even though the K & W stuff mixes with water, can I or should I bypass the heater core anyway? Replacing it would be a royal pain and it’s working great right now. I’m just trying to be careful and think this through before I act. Again, thank you for the service.
I have never had a issue with it before BUT bypassing the heater core is simple and easy to do. The additive is copper flakes that need to come in contact with combustion gas to activate.