Blocked water outlet from manifold

[Flyboy]

I have removed manifold and determined that it is clogged w/ buildup of black hard crud (removed drain plug and can see this stuff)..Symptom was no water exiting with exhaust gas only lots of white smoke after about 3 minutes of running. Plenty of water from discharge hose of thermostat housing to water inlet fitting of manifold...no water comming out of outlet fitting at rear of manifold..Will pouring Muriatic Acid into the manifold actually dissolve this buildup? Or is that a waste of time? Do the 2 top fittings and the gas fitting really need to be removed if it is taken to a shop for the big boilout procedure? They are pretty corroded into the manifold..

[Don Moyer]

Flyboy,

You might have some success in pouring muriatic acid full strength into the manifold and letting it sit for about 15 minutes (household variety muriatic is 30% concentration as it comes from the container). You can sort of predict how well it's working by noting how aggressively the acid "fizzes".

Before going to the hassle of using the acid treatment, you might try working a coat hanger in from each end of the manifold. Sometimes the crud can be broken up rather easily.

If you do decide to take the manifold to a local machine shop for hot-tanking, it's best to remove the freeze out plugs so that the chemicals will have a better chance to reach the front of the water jacket. If the seating ridge around the outside of the hole is deteriorated to the point that you cannot reuse dome type plugs, the machine shop will be able to ream the holes to a slightly larger size and install "Cup" type plugs.

Regards,

Don Moyer

[manfromsnowy]

blocked cooling system

I am not sure if the picture I attached actually made it but I am sending it to show people what the "black crud" looks like when you open up the engine side plate to clear the water passageway.

[forcenine]

Flyboy-
I just went through this with my manifold-it was sending a little water out to exhaust but not compared with the in flow. I used a hand pump and flushed 30% solution through manifold, leaving it in only about 15 min. I didn't have much faith in it but it did make a difference-increased it 50% just not enough for full flow. So pure muriatic acid might do it (although I've ended up at doctor's office before after breathing the 30% so watch out).

I took off manifold, did the hanger, but only upon removing freeze plugs did I really see the gunk well. I soaked the whole thing overnight in 30% which might have done enough but since it was already off, thought I might as well tank it. I had to take the brass fittings off and must now find new freeze plugs. I'll be curious to see what happens once I reassemble.
Good luck ojn yours-I'll be anxious to hear how it goes.
Lisa (forcenine)