My heater turns on and stay on for like 10mins, I found I have a leak inside
There are thre small areas that leak onto the flames and it make it turn off.
My question is there a sealent I can use to fix it?

Without knowing whether this is a furnace. Boiler or water heater, it's hard to answer. But I will add that if the leak is in a water jacket,heat exchanger or similar unit, the element should be replaced. The heat exchanger expands and contracts as it heats and cools so any type of sealer would probably not work.

Thank you so much, but what should I replace it with, dumb ? I know.
About how are we talking about, any ideas?

Any idea what kind of sealer is out there for this kind of problem.
Thank you so much for answering.

My sears model 867 fuel oil furnace will not start now... Its just HUMMMSSS.. I took it apart and cleaned the 2 round probes and the copper tips... It seems the starter or capacitor type box is the issue... that what is humming... Any ideas on what the problem is...

If you are not familiar with the operation of these types of furnaces, you could be putting yourself in danger. Is the humming sounds like a motor is running then shuts off? If that is the situation, it sounds as if you are not getting fuel to it or the ignitor is bad. An experienced tech needs to look at this. Don't try to fix it yourself. In my field of Home Inspections, I have seen homes destroyed by the wrong type of work done to repair these units. Good Luck.