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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Water loss COULD be normal from your high temperature. I would continue until you get the 500 miles or so and then go back to the normal coolant mixture and cross your fingers
Austin, I chatted with you last week about a 2003 Toyota camry with a heating problem. You suggested that I have a cooling system pressure test done as well as check my spark plugs and/or wires for the misfire diagnosis on cylinder #3. If it is indeed internal, i.e., blown head gasket, would you recommend the K&W block seal solution for the car????
Yes I would recommend K&W IF you are absolutely sure you have an internal coolant leak like from a head gasket failure. I am still not convinced you have a head gasket issue…..so prove me wrong.
Austin, I’m sorry that you understood me to say that I was gonna go ahead and use K&W (only if it was indeed that)…I have changed the thermostat and I am getting an overflow from my reservoir when I am driving but not when it is idling. I am headed to the dealership to have it professionally inspected. I do pray that you are right about the head gasket, as there have been none of the usual symptoms, except the check engine light. Thank you very much for your imput, it is greatly appreciated.
Not a problem, good luck
Hey, I have been reading this thread for some time and I just wanted to report some success with trying your method. So, first things first, my car didn’t fail a compression test, though I feel like sometimes cars don’t always do this? My mechanic said that sometimes it takes longer than half an hour for the compression to completely go. Well my story and I will try to keep it short is that my Nissan Sentra 2002,76000 miles, that I just bought has been giving me starting problems from almost the word go.
It was flooding itself on a regular basis and no one could figure it out. My friend/mechanic said compression was ok. Always started right up if left only a few minutes but longer than that, it was hard if not impossible Then it just started to get worse. Eventually it was always flooding itself and white plumes of smoke would come from the exhaust at startup and it would idle rough for a few seconds (also I have to mention sound of swishing liquid under the dash??) The clincher was when it overheated one day and we discovered all the coolant had leaked out (though it wasn’t a really fast leak). I did some looking on the web and decided I would try your method since I can’t afford the headgasket repair right now.
My mechanic drained all my coolant and flushed it and then we put the K and W stuff in. It’s still in the car right now and I’m at 600 miles. Ok, so it has not flooded since the day I put it in! I took in on the highway for 2 hours the day I put it in. The next day, the car started with no problems. I have not flooded the car since. White smoke is gone, no coolant leakage and swishing sound from under the dash is gone (what the heck is that?). The car is driving. I can take it anywhere and know it will start no matter how long it sits.
I do have a question about if it’s better to leave it in even longer? And also it’s brutal hot summer weather right now and I was wondering if I should wait for it to cool a little before draining the sealer. Just to ensure that it seals properly? Thank god for this site and your advice because I’m sure I’d be stuck in the garage still otherwise!( I should add my mechanic had to ground a wire to the coolant sensor too because that was malfunctioning and causing the car to flood. but even after this was fixed the car kept flooding itself)
Great news, thanks for the update. You are correct that a compression test can sometimes not show troubles. That is why I highly recommend a cooling system PRESSURE test. They will take a bicycle pump basically and screw it on to your radiator cap and fill the cooling system with air which will push out the coolant where the leak is making it easier to pin point leaks.
I would drain out the sealer and go back to a 50/50 coolant mix and pray real hard.
The copper flakes in the sealer will create a permanent seal if things work correctly. If not, you MIGHT have to do things over again, but by the report you give I would suspect success.
Hey, I would appreciate some advice.
Just got back from my mechanic. His son pressure tested my coolant system. He believes my 360 is leaking out of a freeze plug inbetween the block and tranny. He told me to try a bottle of ‘Barleak Heavy Duty Stop Leak.’ The black gooey kind, but not the aluminum or copper.
Do you think I should give the KW a try?
I’m getting a lot of conflicting advice, so I’m tentative. I discussed the problem with a friend who’s a mechanic at a Dodge dealership and he said, “never put any of that %$#@ in a coolant system.” I’ve also read on the net of horror stories and people strongly advicing against using coolant system sealant.
Austin, back again….I carried my 2003 Toyota Camry to the dealership and they told me that the head gasket was okay, but my temperature needle continues to go up and then back to the midway point. I changed the thermostat and while it was at the dealership, the temp was fine. I truly am at wit’s end about what to do, any suggestions other than carry it back and let them keep it until it does the same with them. The service manager did mention a radiator cap. Could that be the culprit? I apologize for bothering you man, but I don’t have a clue as what to do….HELP IF YOU CAN, PLEASE!!!
I would NOT use a sealer additive for a freeze plug leak. I recommend you replace the freeze plug, although the freeze plugs are IN the engine block not in between the block and transmission, so I am a little concerned your mechanic is lost.
Good news there is no internal coolant leak.
You will have some fluctuation of the temperature gauge as long as it is in the normal range I would not be too worried about it. If its out of the normal range, then we might have a problem.
Few things come to mind. I would want to dig deeper to determine if the engine IS in fact running hot, or is this a gauge issue?
1. The gauge is not getting the proper signal from the Temperature Sending Unit (not temperature sensor…different part). The sending unit screws into the engine and measures the coolant temperature and sends that info to the dash gauge. These parts dont usually fail often on Toyota, but could be a problem on yours. You can test the sender, but to be honest replacing it is cheaper and faster than testing it sometimes.
2. When does the engine appear to be running hot? If at freeway speeds, then I would suspect a restriction in the radiator and radiator replacement is needed.
3. If the engine appears to run hot at stops or idle speeds and with the A/C on, I would suspect you have a problem with the electric cooling fan motor up near the radiator.
4. If you already replaced the radiator…..cant remember if you said you did or not. I would make triple sure you do not have an air pocket in the cooling system. Sometimes you have to “bleed” the system to get all the air bubbles out after a major part replacement. Best thing to do is visit your local fast lube place and ask them to make sure there are no air bubbles in your system.
Hope this helps