Flushing the FW side

[Yeti]

I had an old Volvo MD2 (FWC converted long ago) that used to give me over heating troubles. I took the heat exchanger to a raditor shop and let them work that over and repair it. There was always a few things that needed some soldering or reworking and it was a flat rate to my knowledge so i let them do whatever was needed.

While the heat exchanger at the shop I would get a gallon of Rydlyme and drop it in a 5 gallon bucket with a another gallon of water. I would set up a system to run that mix through the engine block using an extra pump I had available. I would circulate for 10-15 minutes sometimes letting it sit for a miute or so. Do this a few times until it seemed that the Rydlyme wasn't doing anything and them I would flush the block with freshwater until it seemed fairly clear.

Doing this definitely seemed to help with that old enige running a little cooler.

[rpjn59]

be careful with the silicon sealant. my Perkins 4107 was running hot. and when I opened up the heat exchanger and took off the boots I found giant wads of silicon in there. from the previous owner. unfortunately the removal of the silicon did not solve my overheating problems. she keeps getting hotter when running at full throttle.

[Strait Shooter]

Did you find the cause?

[Nicholson58]

We get zebra muscles here in the great lakes on the FW side. I drop the water level in the groko strainer by about a quart, refill with Clorox, run it into the cooling system & let it set for about 5 minutes. I only do this before motoring out so the system will be well flushed. This keeps critters out of the heat exchanger. Clears algae slime as well.

[MarkSF]

Originally Posted by rpjn59

be careful with the silicon sealant. my Perkins 4107 was running hot. and when I opened up the heat exchanger and took off the boots I found giant wads of silicon in there. from the previous owner. unfortunately the removal of the silicon did not solve my overheating problems. she keeps getting hotter when running at full throttle.

That's exactly why I always use a non-setting gasket compound for engine work, like Permatex #2. It won't clog anything.

[Cuttyhunk]

There are some newer, nontoxic antifreezes out there (West Marine sells one). They do not mix with the toxic antifreeze and will produce gunk if you do mix them. This may have happened in your boat.

I changed out my system in a previous boat and flushed it three times with water before using the new nontoxic stuff. It was a pain to do, and then I had to be careful no one unknowingly dumped some of the toxic stuff in there without realizing it would be bad for the system. I try to leave a clean wake, but have decided to stick with the toxic stuff in this boat. Until it is banned, anyway.


Sent from my iPad using Cruisers Sailing Forum

[Strait Shooter]

Originally Posted by a64pilot

Clyde has a good point, if your engine is wet sleeved, make sure your coolant has the additive for cavitation so you don't end up with pin holes in your cylinders.

O.K., what does "wet sleeved" mean?
And what kind of additive prevents cavitation?
And how does that lead to pin holes in what cylinders? The heat exchanger?

[jimbunyard]

Besides being a Volvo, is this your engine?



If so, it is unsleeved, the cylinders are cast into the block.

A wet sleeved block has separate liners that are sealed to the block using sealrings and the coolant circulates directly against the outer surface of the liner. A dry liner is pressfit into the block and heat transfer is through the liner, into the cast iron of the block and then removed by the coolant.

Don't know what type coolant or additive prevents cavitation.

Cavitation is, generally speaking, the erosion of metal caused by the explosion of microscopic bubbles induced by pressure differences, in a fluid containing dissolved gas, at the interface of the metal and fluid.

As far as the caveats concerning silicone.

By all means be careful when using it (or anything else). If anyone is "gooping on" any kind of sealant, they are not in control of the situation and are likely to cause more harm than good.

But silicone, like permatex #2, or the various types of Loctite, or never-seize, or any other of a multitude of chemicals, is very useful and necessary in the proper context.

And in this context the proper sealant and application is this:

When you get the tube bundle out of the heat exchanger assembly, check the bundle for cleanliness, leaks and blockages. Correct any shortcomings there. Inspect and clean the boots and clamps, replace as necessary. Dry the bundle, the heat exchanger housing and boots. Insert the bundle into the housing, big holes down (or bleed hole up, whichever is appropriate), and center in the housing. Smear a light coating of silicone on the protruding part of the bronze tube bundle and push the boot on to it and the cast part of the heat exchanger housing. Do not put silicone on the cast part of the housing unless you want to fight with the boots when you remove them in the future.

The point of the silicone is to actually glue the rubber to the bronze of the tube bundle; with the addition of the clamp it is just an another line of defense against mixing of seawater with engine coolant. There are a lot of conflicting pressures and temperatures operating against each other in this particular system, which allow movement of components beyond that which might be considered normal in a typical heat exchanger system.

Given the black coloring of the residue in the engine side of the system, I'd hazard a guess that mixing was already going on.


And an M50

[lancelot9898]

Several years ago a diesel mechanic told me that most truckers were using the heavy duty antifreeze in their rigs to prevent corrosion and pitting on the cylinder liners. At the time I did not know if I had wet cylinder liners or dry in my Perkins 4-108 so I just switched to the Prestone heavy duty coolant making sure that I flushed the system well. I have dry liners so that was not necessary, but maybe the heavy duty coolant provides better corrosion protection anyway and when I refresh the system next year, I'll keep using it not wanting to do a heavy flush of the system. Apparently the two different antifreezes do not mix well.

[a64pilot]

I can link to papers, but sometimes a picture is worth a thousand words. Basically during combustion a cylinder will "ring" or vibrate, this causes bubbles that collapse and cause erosion of the cylinder form the outside.
There are coolants specifically formulated to prevent this, usually almost always a good coolant make for big Diesel over the road trucks is a good one.
https://www.google.com/search?q=cavi...w&ved=0CCsQsAQ

[a64pilot]

Oh, and the reason to remove the thermostat is to allow rapid coolant flow through the engine, you are trying to flush out everything. I leave the drain open and continually fill the engine to help this flushing process, That way I can flush a bunch of water through the engine in a short time, if you simply do the drain and fill thing, your not flushing as well and it will take several cycles to get everything out.
Once you get her clean though a drain and fill is all that is required to keep it clean, your having to clean up after someone else's lack of preventative maintenance.

[Strait Shooter]

Originally Posted by jimbunyard

Besides being a Volvo, is this your engine?



If so, it is unsleeved, the cylinders are cast into the block.

A wet sleeved block has separate liners that are sealed to the block using sealrings and the coolant circulates directly against the outer surface of the liner. A dry liner is pressfit into the block and heat transfer is through the liner, into the cast iron of the block and then removed by the coolant.

Don't know what type coolant or additive prevents cavitation.

Cavitation is, generally speaking, the erosion of metal caused by the explosion of microscopic bubbles induced by pressure differences, in a fluid containing dissolved gas, at the interface of the metal and fluid.

As far as the caveats concerning silicone.

By all means be careful when using it (or anything else). If anyone is "gooping on" any kind of sealant, they are not in control of the situation and are likely to cause more harm than good.

But silicone, like permatex #2, or the various types of Loctite, or never-seize, or any other of a multitude of chemicals, is very useful and necessary in the proper context.

And in this context the proper sealant and application is this:

When you get the tube bundle out of the heat exchanger assembly, check the bundle for cleanliness, leaks and blockages. Correct any shortcomings there. Inspect and clean the boots and clamps, replace as necessary. Dry the bundle, the heat exchanger housing and boots. Insert the bundle into the housing, big holes down (or bleed hole up, whichever is appropriate), and center in the housing. Smear a light coating of silicone on the protruding part of the bronze tube bundle and push the boot on to it and the cast part of the heat exchanger housing. Do not put silicone on the cast part of the housing unless you want to fight with the boots when you remove them in the future.

The point of the silicone is to actually glue the rubber to the bronze of the tube bundle; with the addition of the clamp it is just an another line of defense against mixing of seawater with engine coolant. There are a lot of conflicting pressures and temperatures operating against each other in this particular system, which allow movement of components beyond that which might be considered normal in a typical heat exchanger system.

Given the black coloring of the residue in the engine side of the system, I'd hazard a guess that mixing was already going on.


And an M50

Yes, that's my engine. I appreciate everyone who has taken the time to respond, again, many thanks.

Thanks Jim for the diesel lesson, so the pitting from cavitation in an unsleeved engine isn't an issue then (in this case). Thanks also for the silicone tip. That makes sense. I will use your advice, much appreciated.

This will be the second place I've used silicone on the boat. I used it between two metal parts on a windlass to keep the lanacote separated from salt water spray. As you say, there are a multitude of necessary chemicals, that if used properly are invaluable.

So, aluminum head, unsleeved, what's the best antifreeze to use? I like the glorified snake pilots recommendation of a mixture that's a little heavier on the antifreeze and plan on doing that.

Is it overkill to replace the thermostat? I could always use the spare anyway, and I can see how the removal of the thermostat prior to flushing would aid in circulating the gunk remover better, no?

And one last point, I keep reading about using distilled water for flushing, and then using it in the antifreeze mixture. I guess it's not that big of a deal to use it, but damn, I've never used distilled water in a cooling system before. Have I been doing it wrong all these years (it wouldn't be the first time).

Again, thanks for all the help and input, I'm sure people searching like I was, will appreciate the comments as well.


John

[Strait Shooter]

Hhhhmmmmmm
I just noticed that the MD22 doesn't have a manual oil pump for evacuating the oil from the engine.
I wonder why they did that?

[Strait Shooter]

Originally Posted by a64pilot

Oh, and the reason to remove the thermostat is to allow rapid coolant flow through the engine, you are trying to flush out everything. I leave the drain open and continually fill the engine to help this flushing process, That way I can flush a bunch of water through the engine in a short time, if you simply do the drain and fill thing, your not flushing as well and it will take several cycles to get everything out.
Once you get her clean though a drain and fill is all that is required to keep it clean, your having to clean up after someone else's lack of preventative maintenance.

Whoops, you already answered my question.........thanks

[Strait Shooter]

The amount of gunk built up on the heat exchanger tube stack was pretty bad. Over a third of the holes are closed completely.

Now I can't get the tube to release from the heat exchanger body. I think it's because of hard crud build up at the meeting surfaces. Any ideas on getting this to release? I used a block of wood and a small trim hammer with no results. I'll try again today with a 5lb hammer.

I was thinking of removing the entire heat exchanger and bringing it into a radiator shop.w

Anybody?

I can see where some Permatex #2 would have prevented this build up at the mating surfaces.