I poured blue devil engine sealant into my engine as a quick fix for my head gasket problem. It's made the issues worse now there is what looks to be white rock salt in my radiator and heater core and in the rest of the cooling system. What is the best way to get all of this sealant out of the cooling system?

Thank you

2 Answers 2


If it is not sticky, then you can use a garden water hose, as long as you have a better than good flow rate, fit the hose to the bottom rad hose and feed the output from the top hose into a large bucket.

Use the full flow rate but it may be easier to remove the thermostat - otherwise you have to have the engine running hot to open the 'stat... Even if you remove the 'stat then it can help to have the engine running but it won't get hot.

Also, do the same for the rad...

If it is sticky then you may consider a tank and external pump to do the same thing, oh and be VERY careful if you add a chemical to help remove the "sludge". Make sure it won't kill the seals.

Done this in the past, but not for that product.


Ok so I know this is an old post but I’m leaving this here for anyone frantically searching like I recently was. It took days to clear my system and after a couple weeks she’s been running well again. I ran two vinegar flushes back to back and two separate Prestone flushes. Between each I covered my engine bay with plastic, popped the radiator cap and pulled the hoses off my heater core up by the firewall. I blasted air through each hose with the air compressor (shooting it out of the top of the radiator), filled with water and blasted it again over and over until it came out clear. I also ran air through my heater core in both directions while the hoses were off. It took several attempts over several days but I think I finally got it. Prior to this I changed my radiator, water pump and thermostat.

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