Followup to "no raw water thru Exhaust"

[rfrye1]

Yep, it was a blockage (gunk) at exhaust elbow. The guy that was helping me from a marine shop suggested I run Boric Acid thru the system to clean it out. Has ANYBODY heard of this? What's your opinion?

Thanks.. Bob

 

[Tim R.]

I used to do an annual acid flush on my raw water cooled A4 wth muriatic acid. You wat to follow this up wth a neutralizer and plenty of fresh water.

 

[rfrye1]

Tim R. Did you "cut" the M.Acid, or put thru at 100%??

 

[Rick D]

I used to do an annual acid flush on my raw water cooled A4 wth muriatic acid. You wat to follow this up wth a neutralizer and plenty of fresh water.

I did the same on my 3GM that was prone to cake up. I used a diluted MA. Never had a problem after that (but was also more careful to avoid long idling or low RPM powering for extended periods.)

 

[Alan]

Muriatic acid is

.. not such a good idea. You may want top give Barnacle Buster a try instead. It is not only harmless to your engine and cooling system parts but is also biodegradable. It is safe for flushing all kinds of water cooling systems such as A/C units and refrigeration coolers as well.

 

[Tim R.]

Tim R. Did you "cut" the M.Acid, or put thru at 100%??

It has been a few years but I think I recall mixing it 50/50. Always pour the acid into the water; not the other way around.

When water is added to muriatic acid, an exothermic (heat is given off) reaction occurs. This is often accompanied by a violent "belch" which propels the acid mixture out of the container and onto the person making the dilution! This occurs because the heat generated by the reaction is under the cooler water and causing it to expand rapidly. When the acid is poured slowly into the water, the cooler water layer is on bottom, so the heat generated is dissipated upwards at a slow speed.

 

[Steve Dion]

I suggest that you replace the elbow and then see if you can remove the carbon build up. It is usually harder than the cast iron that it is made from. There is often a lot of corrosion between the exhaust and water jacket (which ends up rusting out).

If yours is in good condition you can save it for the next swap.

These things are very difficult to remove from the manifold, so be prepared to use some very large pipe wrenches with extensions to get them apart. You may also want to consider having a torch around to heat up the parts.

There is a coupling that goes between the manifold and the elbow. This unit has a left hand thread on one side and a right hand thread on the other.

You may be able to review these unit in the photo forum if they are still there.

 

[RichH]

ummmm muriatic is typically only 35% strength Hydrochloric. Muriatic will dissolve any base metal of the engine internals exposed and will also totally destroy any protective formation of ferrous rust (blue/blact rust). Using muriatic/hydrochloric acid in a cast iron engine is a VERY bad idea - it can also lead to 'slab rust' in the exhaust manifold, etc.

Better to use an inhibited commercial boiler descaler compound such as Rydlyme or Marsolve, etc. ... doesnt attack the base metal as does muriatic/hydrochloric.

 

[Tim R.]

ummmm muriatic is typically only 35% strength Hydrochloric. Muriatic will dissolve any base metal of the engine internals exposed and will also totally destroy any protective formation of ferrous rust (blue/blact rust). Using muriatic/hydrochloric acid in a cast iron engine is a VERY bad idea - it can also lead to 'slab rust' in the exhaust manifold, etc.

The acid is not left in the engine long enough to cause any long term issues. And you always neutralize it when done. The A4 in my '77 Pearson had this performed on it every season and it is still running strong.