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Mcm170Head

"1985 mcm170, had some running

"1985 mcm170, had some running issues( found water/ antifreeze)number 4. Pulled the head and had it checked at a machine shop, no cracks or leaks.When i pulled the head i found 1/8-1/4 of water or antifreeze in number 4. Checked the riser it was full prior to pulling,the head. Found some sort of crystallized material resembling rock salt around/between the 3-4 cylinder wall. I have no clue where this could be coming from. I just don;t want to put it all back together and have the same issue. I was going to fill the riser and check it, but since it was full i am some what inclined to think it was the head gasket.The cylinders looked fine a little rust in number 4 but i turned it over and felt the enitire cyl wall and did not notice anything out of the ordinary.
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"hi, just had the same problem

"hi, just had the same problem with mine, head was fine but head gasket was shot, this was on a rebuilt 170 with only three hours of run time. i am also getting the rock stuff you mention...dunno what it is or where it come's from, not much there but it is some in the cooling system and everything has been cleaned and checked by a machine shop. i put mine back together with the best gasket i could get ( a sever duty one) and just ran it last night on the hose at home, it all check's out good for now with 175 psi compresssion on all cylinder's so hopefully i got it right this time... will find out when i hit the lake again. anyway let me know if you find out anything on the mystery sand stuff...goodluck and torque the head good and in steps when you put it back together and clean all the thread's and stuff to get a good torque on it."
 
"Everyone: Please comment.

"Everyone: Please comment.

Are you guys using a quality antifreeze designed for use with aluminum and mixed with distilled or deionized water at a 50/50 ratio? If not, you are setting the stage for galvanic corrosion which comes from a minute electric current which is produced by a chemical reaction between dissimilar metals and accellerated by mineral based water.

The crytals that you are seeing are mineral salts that form during the previously mentioned process. Years ago when autos used copper radiators, the crystals you are seeing were called solder bloom. I actually saw some of the crystals larger than golf balls in the bottom of the radiator of my 72 Dodge Charger after just one year, just out of warranty. Sure do miss that machine! It was a chick magnet that would S & G! The wife hated it and told me after it left my life. Where did the time go?

There is an inexpensive cathodic annode system for use on vintage automobiles, hotrods, etc. that could work in a marine application to prevent the growth of the mineral crystals. It works just like the mercruiser annode system.

Come to think of it, you may be able to retrofit the mercruiser cathodic system to your engine and O/D.

Please provide your expertise to this opinion from an individual without a scientific background.

Guy"
 
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