4-108, Cleaning gunked cooling system

[Trekka]

I've been steadily dismantling the cooling system on the old 4-108. I bought this boat as an estate sale, and have been refurbing it.

Like everyone else my 4-108 overheats. It is now clear why.

Problem #1
The heat exchanger is almost completely clogged, although receipts showed that only a few years ago the PO had it removed and cleaned by a radiator shop. That's why I didn't check it first.


After several dosings of muriatic acid and reaming out all but one of the tubes was clear.

I had to remove the coolant reservoir to get at the thermostat. (I would happliy flog whoever designed this...) It took a long time but I finally got it free. What a mess - the thermostat was gunked up!


In fact the whole coolant system plumping has a thick slime coating, with a waxy buildup in places, as can be seen on the thermostat, and on the hoses in/out of the manifold cooling jacket:


I took the reservoir home and opened it up and cleaned it out:


After a week I was ready to reassemble the reservoir, and paint it and the two metal pipes I brought home from the engine.

Now, if I can figure out how to finish rebuilding the water pump">raw water pump (separate thread) I can begin putting it all back together - after I have cleaned out the rest of the system. Suggestions?

In any other engine I'd leave the thermostat out, run water and cleaning solution (which?) through it a couple of times before final rinse. Then install the thermostat and add coolant. But with this engine (grrr...) I don't want to take the reservoir off again so I'm going to have to have the thermostat in place from the start. I hate the thought of all that slime going through the heat exchanger and the thermostat. Any ideas on how to clean the engine plumbing before reassembly?

[Stillraining]

Im curious as to why there even is all this gunk in your fresh water side..I look forward to others thoughts..Im thinking you must have a leak in your exchanger or elsewhere allowing raw water to mix in... other wise its not making sense to me.

FWIW
you can safely run your engine from dead cold for a couple minutes with out a heat exchanger by bypassing it as long as you can circulate your fresh water side internally for some cooling ..therefor being able to rig up a filter bucket with even a simple cheese cloth filter or some other combination you figure out.

[Trekka]

Very good question. And the info I have found so far suggests that the PO mixed coolant types. Contrary to what the labels say, mixing coolant types can cause silica and other ingredients to precipitate out of one of the coolants. Most auto and marine stores only have a couple types of coolants. But when given a larger choice and the time taken to read the labels a number of variants emerge. Some, such as I will use next time, are silicate free.

While on the subject of coolants (and I've been reading up and asking a bunch of questions of sources lately) there are also reasons not to use the new "Organic Acid Technology" coolants:

OAT stands for Organic Acid Technology. OAT antifreeze is not made from grain. Some organic acids can be used as corrosion inhibitors instead of the traditional inorganic inhibitors, like nitrites and silicates. OAT antifreeze should only be used in newer vehicles designed for its use. Organic acids actually attack the lead solder used in the radiators of older model vehicles.

[Trekka]

In addition to the info above I found this:

There is a class action suit pending against GM claiming that cooling systems were corroded and sludged up due to the extended life antifreeze Dexcool. Below is text from the lawsuit:

Dexcool was initially marketed as a long life universal automotive engine coolant that would last for 5 years or 100,000 miles of service. It is now marketed to last for 5 years or 150,000 miles of service. Manufacturers of traditional antifreeze/coolants generally market that their antifreeze/coolants will provide dependable thermal control and corrosion and rust protection for twenty-four (24) months or 30,000 miles. The major difference in Dexcool over traditional coolants is in the corrosion inhibitor protection. Traditional antifreeze/coolants contain inorganic salts of borate, phosphate, silicate and other chemicals to prevent rust and corrosion, whereas, Dexcool’s® corrosion inhibitor components, are based on organic acid technology (OAT). Dexcool is orange and traditional antifreeze is green.

[Stillraining]

Never did like that orange color...

[Chief Engineer]

Could it be some type of aftermarket radiator sealer?

[GordMay]

Since antifreeze is clear when it is manufactured, and water is clear, dye is used to colour the antifreeze for identification, and marketing purposes. The colour of antifreeze is no longer an accurate indicator as to whether it is an IAT, OAT, HOAT or NOAT formulation.
Different manufacturers may use different dye colours delineating different chemisties.

The Colour of Antifreeze:
http://www.filtercouncil.org/techdata/tsbs/05-2.pdf

[CSY Man]

I have the same engine in the same boat but never had the cooling system gunk up.

Always used the yellow can, Prestone 50/50 with water. The coolant stays good year after year, but I do change it every now and then..Probably 3 times in 10 years or so.

Did an initial rinse with some blue chemical, but not sure if that was needed. Some guys said to never used anything but Prestone.

[Stillraining]

Well I learned something...I never new antifreeze wore out..I have never changed it anything I have ever owned.

[Trekka]

Yes, antifreeze/coolant does wear out in use, as well as have a shelf life in storage. And there are special formulations for heavy duty diesels. I'm learning a lot reading up on this and comparing commentaries and spec sheets. Gord is right, color is not a definitive identifier. And Prestone makes different formulations, though it is common for only one to be in the typical consumer auto owner store or department store. But given a lot of choices somewhere, reading the labels is advised. Hopefully I can come up with a crib sheet on what the label's contents indicate. I'll try and post a summary once I get done with this cleaning & reassembly and am confident my report makes sense.

But one issue that caught my attention was the possibility of cavitation induced along the cylinder exterior wall that can result in pockets with loss of contact with coolant, resulting in hotspots. Fleet diesel coolants have additives that resist that. I think aftermarket additives like "water wetter" may do the same.

Some heavy duty diesel app coolants need an additive recharge peridocially, and some come with a filter that is designed to release such additives over time. But I think for the typical size engines we have that is not an issue, rather being for very large, constant use under heavy load engines such as long haul trucking.

What I am focusing on in all the info are issues of conflicts between antifreeze/coolant formulations, including aftermarket additives, that can result in what I am cleaning out of this engine I'm working on. And that's what I'll report back about later.

[Stillraining]

Nal-cool is one of thoes products you speak of as is the spin on canister type you refer to that slowly dissolve into the system. These are electrolysis inhibitors though and do nothing for antifreeze properties.

I run a fleet of heavy equipment and we use nal-cool by the case but other then occasionally topping off radiator levels with new antifreeze we have never changed any out and have yet to freeze up a motor in 22 years... but it dosent get that cold here either 11 degrees was the coldest I ever remember.

Not arguing mind you... but I dont change my oil in my car every 3000 either I add a zero and I have cars with 220 on them sitting in my driveway...they dont burn or smoke a drop either...so I just have differnt takes on things.

It's a conspiracy man.....

[Chief Engineer]

In any engine that has any aluminum components!!!!!!!

This was demonstrated to me
at a YANMAR ENGINE SCHOOL.

It will seriously degrade the aluminum.

I typed this this way to mak a point.

[Stillraining]

Good to know thanks.

[GordMay]

Was there a specific "Nalcool" product that Yanmar proscribes?
Nalco makes several "Nalcool" products, including some intended for use with aluminum components.
Nalco Company - Water Treatment and Process Chemical Technologies