Sealing porous heads?


Just another Tim ;-)
I posted this initially in the general tech forum but didnt get alot of response so I am trying it here since you all deal with aluminum heads more frequently.

I have recently aquired a set of M&A heads. Upon pressure testing it was clear that they have a porousity problem. there is a total of 6 leaks between the two heads. All but one of the leaks are external with the one leaking under the valve cover. All of the leaks have been attemted to be repaired by a previous owner via either welding or apoxy unsuccesfully. I have heard about GM tablet sealer, Irontite and K&W sealer which all would be done after install. A freind mentioned some type of ceramic coating that would be poured into the coolant passages, adhearing to the inside of the passages and sealing from the inside. Do any of you know about this process? What is it and where can I get it done? Is there any other type of sealer or process (permanent) that can be done to fix the porousity of the coolant passages with the heads off the car?

Any ideas?

My friend you may be in touble.
Idaho GN had to get rid of a set of M&As
that just would not stay together.

I had a set of ported iron heads
that I spent $500 on the ceramic fix.
It did not work!
Boy, Tim, the joy just keeps flowing with those heads, eh? Call Polydyn ( and see if any of their coatings will work. A couple of engine builders I know really like their heat barrier and anti-scuff stuff.

Moroso has 2 kinds. 1 for use w/ antifreeze and 1 for plain water.
I've used it for leaks at freeze plugs.. worked in about 5 minutes.. never had a problem since..
Chuck is right even though he is up past his bedtime. I have used it in engines that have been frozen and have visible cracks above the lifter bores. I turn my engines 82 to 8500 and have never had one leak after sealing it with that stuff. If that doesn
t work you probably will have to head for the nearest dumpster.

I have found K&W block sealer to be very effective with problems such as your's. You have to follow the instructions on the can to the letter. Flush all the coolant out of the system. add water warm the engine up to temp.with the rad cap loose.Then add the product with the engine still running tighten the cap & build up some press. to force the stuff into the porosity run for about 10 min. drain completely including block.Remove spark plugs to let air in to the Cooling system & cylinders & let sit till engine cools own for at least four hours to give the stuff a chance to harden good.
Refill with water & test. Don't add coolant untill you'r sure that the process worked. Coolant will eat up bearings alot faster than water.Should any get into the pan.If you see good results initially You may want to repeat the process for insurance. Good Luck!
Ooooh, thats not a good sign when the first post to either thread mentions being out of luck or dont use em' :(

I have a ? on the Moroso sealer. If I initially use the ceramic sealer with water can I put antifreeze/coolant in at a later date? Will the coolant destroy the seal or does it prevent it from working at first and then no effect after setting? The problem is I intend to use them on the street and do not have a garage for storage in cooler months.

No pun intended eh? My experience with this particular purchase certainly brings new meaning to the saying "I got screwed".
Well Now,
If this Moroso sealer does the trick on my Ram, I'm going to have to buy someone a beer. I've tried ALOT of different things and only ended up with a new radiator because of a plugged up one. (BARR's ugh!)
I have a leak at the front of the cylinder head where the casting mold came together, right at the thermostat.
It started leaking @ 105K:mad: Made me happy and I enjoy adding water at the start of the day to make up for what leaks out overnite :mad:

I agree with Ron Tarabori and Chuck.

I have used Moroso Ceramic Engine Seal in everything from Late Model Dirt engines (between races), Asphalt Nascar engines, Drag Race , Street , and pulling Tractor engines.

IT DOES WORK !!!! In most cases if used as directed.

Part # 35500 is only to be added to system after anti-freeze has been drained and flushed. Or in systems that only use water. But , after proper treatment anti-freeze can be added back to system. ( with this part # you just can't added it to a system that currently contains anti-freeze ).

Part # 35520 can be used in a cooling system while anti-freeze is still present.
As Ron said, " if this doesn't stop the leaks , look for a dumpster."

Moroso says "If this doesn't stop the leaks, find yourself a welder!"

I would highly recommend it's use in many cases.
Good Luck

We used the moroso stuff years back in an automotive shop. When a customer just ddin't have the cash for a new head we put it in an most times would solve the overheating/overboiling problems. Quad4's and the chevy 2.2l engines heads cracked alot.