Do products like Thermagasket or K W block seal work even moderately well as a temporary fix for a blown head gasket and if so which brand would be preferable?

Answer 1

I've used Gunk Block Seal on two early eighties cars that my two U student kids drive for errands and occasional 3 hour excursions. The vehicles are not worth repairing properly but are safe otherwise. The fix lasts about 6-8 months after which time you have to do it again. Not a bad trade off to extract a bit more service from an otherwise decent vehicle. Apparently, after several of these treatments, you will start gumming up the pinch points (rad and heater core).

Answer:

I have had GREAT success with K&W block seal for use in repairing blown head gaskets. The trick is:

1. You first have to drain ALL coolant.

2. Add 1 or 2 cans of Block seal depending on size of engine.

3. Fill up with water.

4. This is where it differs from directions on the can. DRIVE YOUR CAR AS YOU WOULD NORMALLY, this will allow for the product to seal properly. It may take a day or 2 but It will seal, I promise!

Hey it surprised me too but it made me a believer. That was 2 months ago and I still haven't drained it out and I wont until it gets cold and its time for the antifreeze!

The way I see it, what have you got to loose if you're facing head gasket repair cost. I avoided spending 800 to 1200 by spending $8 for 1 can I call "magic serum."

Answer:

I just used the K&W Nanotechnology block seal (green bottle not the can) and it worked perfectly. I did a lot of searching and most of the info I found was skeptical and opinions. Let me say again I DID use K&W and it DID work. I am speaking from personal experience. I would also like to add that, yes it is very important that you follow the directions exactly. The part where it says to drain flush and repeat, I repeated this step an additional time to be absolutely certain that ALL coolant/antifreeze is out of the system. I agree with the above about leaving it in your system before you drain and refill with coolant/antifreeze. Initially after you idle your engine for the 30min, do allow the 12hr curing stage, then depending on the severity of your problem leave it in and drive normally before you drain and LET DRY AGAIN. Flush one final time and refill with coolant/antifreeze. I hope this help people who are looking for real life experience with this product. The $20 USD I spent on his bottle was definitely worth it compared to the $1000+ on replacing the parts in a shop. Mind you if you do have the money you should do it the right way but in a pinch and on a budget I will recommend this to everyone who is willing to take the little bit of time and follow the directions.