What is a good block sealer that wont clog up a radiator?

Once hot, it doesnt leak at all, but if it sits in my trailer a week, it leaks probably a pint of water. Enough to be annoying. It leaks around the head gaskets near the short studs. Would rather not pull the heads.


Thanks

I don’t have any advice Bill, but am curios what head gaskets you are using?

They are felpro, I never had problems before, I may try to retorqe the heads and see if that helps.

To me......

By default if the block sealer is any good it will plug up the radiator because what is a radiator? A bunch of small water passages and that's exactly what block sealer is supposed to do, plug up small water passages. Every time i have used these products on a passenger car, they have never repaired a "cracked head" or leaky head gasket as they claim to do, but have almost always plugged the radiator. I have never used in a racecar.

If you put this in your racecar, pick your favorite brand (i think K&W in the copper colored can is good), bypass the radiator and attempt to follow their directions for warm up and cool down, then drain and flush the cooling system a few times, id' make sure there is none left in the system at all, then hook radiator up again.

quote:

Originally posted by banjo:
They are felpro,

Composition Type or MLS ?

I put sealer/stop leak in every fresh engine I've ever had. Bar's Leaks in pellet or liquid form, Alumaseal. Probably 15-20 bottles of that stuff have been through the same radiator on my Nova over 25 years.

Bill these worked well for us.

https://www.amazon.com/Genuine...a-568759644470&psc=1

Use some GM seal tabs.

They are composite gaskets. Thanks for all the input.

Best stuff made is called DIKE. Our local NAPA store keeps it. Will not stop up the rad. and drains out with the water when you dump it.
https://www.conklin.com/dike

X2 on the K & W Block Seal! My in-laws cracked a head or popped a head gasket in their Motorhome 45 min after leaving my house. I towed them back to the shop and put a can of K & W in it followed the instructions, and it got them all the way back to where the h_ll they came from! Love that stuff, it would have been worth paying $100 a can to me!

I have used Moroso Ceramic sealer in a pinch and it works very well. You need to follow the instructions EXACTLY. Be aware if you have multi layer gaskets sometimes the leak path is between the layers. This can be very difficult to stop completely.

May do a little research about black pepper. Maybe it's a wives' tale but a stock/ss guy I know believes in it.

quote:

Originally posted by bry-war:
May do a little research about black pepper. Maybe it's a wives' tale but a stock/ss guy I know believes in it.

It works, but every leak is a different situation.
I have used pepper, it was a small leak. I t worked for a couple of weeks.
There is no magic permanent sealer.
Find the problem,and with layered gaskets it is usually finish or flatness.

quote:

Originally posted by Kenneth:
Use some GM seal tabs.

Yep, GM seal tabs or Wynns stop leak. Either one will stop the leak you have but not plug anything. Once you drain the coolant they're gone. IE, if you drain the coolant the leak will come back if you don't add it again.