Anyone use K&W Block Seal, Thermoseal, or Cargo Seal?

SavageUrge · **Posted:** Sat Jan 17, 2009 12:29 pm

I fear I may have the beginnings of a head gasket failure (s-l-o-w-l-y losing coolant + mucky foam under the oil cap) so I've been reading up on the products listed above or any other brand of permanent block sealant. Some people swear by them or one in particular, and others are vehemently against them! So naturally I turn to YOU, my KJ brethren, whom I trust exclusively on matters Jeep! I've read that these wil last a long time or Sh*t the bed after a couple hundred miles. I've read that sometimes they tend to clog portals that shouldn't be clogged. If I had the money to have a diagnostic done or have the heads /gasket replaced, I would obviously do the right thing, however I don't, so I'm going this route. Have any of you used one or more of them and would you recommend any of them. Thanks a million guys and gals!

jeepkj02 · **Posted:** Sat Jan 17, 2009 12:57 pm

The "mucky foam" underneath the oil cap could be normal condensation. Many threads about it on here and JKJ. Usually happen around winter time or if you make a lot of short trips. Check your oil dipstick, if there is a milky foam on there they you have coolant in your oil (leaky head gasket). Loosing coolant could mean you have a small leak somewhere, start looking at your radiator hoses, water pump, etc...

Jeepjeepster · **Posted:** Sat Jan 17, 2009 12:59 pm

jeepkj02 wrote:

The "mucky foam" underneath the oil cap could be normal condensation. Many threads about it on here and JKJ. Usually happen around winter time or if you make a lot of short trips. Check your oil dipstick, if there is a milky foam on there they you have coolant in your oil (leaky head gasket). Loosing coolant could mean you have a small leak somewhere, start looking at your radiator hoses, water pump, etc...

Exactly. Usually you will get the milky crap if you use cheap oil. I make tons of short trips and Ive yet to see it with Valvoline SYN. Never saw it with Mobil 1 either but Ive read posts where people got it.

Check the rad for leaks like jeepkj02 said.

sleeve84028 · **Posted:** Sat Jan 17, 2009 1:07 pm

Yup, In the winter you need to clean out the condensation every two weeks. The oil fill tube acts like a chimney where hot gasses (from the engine) travel towards. The hot gases are then exposed to the cooler ambient air temperatures and that is where the condinsation forms.

Keep the PCV valve new.

Clean out the tube every two weeks

I do use Mobil1 and deal with this problem every winter. But then again, I live 8 miles from work and most trips are less than 30 minutes.

SavageUrge · **Posted:** Sat Jan 17, 2009 2:03 pm

I have had the foam before regardless of the oil I use (ONLY Mobil 1 Full Syn or Valvoline Full Syn), however I read a post where this could be a symptom of a leaky head gasket, so I threw it in there. HOPEULLY it is just a pinhole leak in the rad or other component. I'd still like some feedback on the sealants though, just in case of a worst-case scenario. Thanks again!

Anyone use K&W Block Seal, Thermoseal, or Cargo Seal?

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