caseclosed
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Transmission cooler corrosion
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The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
RT Firefly
Enigma
Greetings,
Mr. c. Slightly loose hose clamp. If of concern, remove clamp and hose, wire brush off the corrosion, repaint and put hose and clamp back on. Some members use a "sealant" on the fitting (can't remember what but I think it's a Permatex product.)
Man, that looks like a PRISTINE engine space! I'm jealous.
Mr. c. Slightly loose hose clamp. If of concern, remove clamp and hose, wire brush off the corrosion, repaint and put hose and clamp back on. Some members use a "sealant" on the fitting (can't remember what but I think it's a Permatex product.)
Man, that looks like a PRISTINE engine space! I'm jealous.
bshanafelt
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when was the last time this cooler was replaced?
They have a service life.
The OEM cooler on my gear (hurth) was 10 years old when I thought I would 'service' it for winter by draining it. - the drain plug & receiver was so corroded (Not visible from observation) - that it sheared right off as I twisted it with a wrench.
The good news for my case was that there was not rot in the cooler between the circuit of raw seawater & gear oil -- I feel like that was a great stroke of good fortune.
I now replace these on a 5 year cycle, no questions asked. A 20 minute job.
Also, get the cupro-nickel version instead of the slightly less expensive version.
good luck.
They have a service life.
The OEM cooler on my gear (hurth) was 10 years old when I thought I would 'service' it for winter by draining it. - the drain plug & receiver was so corroded (Not visible from observation) - that it sheared right off as I twisted it with a wrench.
The good news for my case was that there was not rot in the cooler between the circuit of raw seawater & gear oil -- I feel like that was a great stroke of good fortune.
I now replace these on a 5 year cycle, no questions asked. A 20 minute job.
Also, get the cupro-nickel version instead of the slightly less expensive version.
good luck.
READY
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Based upon OP info it appears to be a 2018 boat. Thus pristine engine space 
. Many of us with older boats (like me with a 45 year old boat) would love to match that condition!
. Many of us with older boats (like me with a 45 year old boat) would love to match that condition!
firehoser75
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Caseclosed:
Based on the age of your boat, I would agree with RTF!
However, the raw water cooling system requires regular maintenance if you want to avoid potentially BIG issues. Without this maintenance, a person is relying on good luck and in boating that is not a good path to follow in the long term.
All of these components should be taken off the engine and fully serviced (which includes pressure testing) every 5 (4-5) years at most (unless you regularly freshwater flush your engine's raw water cooling system after use... then the time can be extended for a couple of years or so). Leaving the engine sitting full of saltwater for extended periods (even regular operation using saltwater for cooling) accelerates what can be termed "marine age" which shortens the overall life of the engine. Freshwater flushing is easy, and it works!!!
Issues that can develop without regular maintenance include:
1)Engine overheating. Overheating can lead to severe damage requiring major repairs.
2)Saltwater intrusion into areas you don't want it! Eg. Aftercooler can allow saltwater to enter the air intake. Gear cooler can send saltwater into the tranny or send the tranny oil out the exhaust. HX can send saltwater into the engine coolant (antfreeze). Exhaust elbow leaking internally can send saltwater into the turbo or exhaust side of the engine (in a poorly designed exhaust system - many examples out there in service) or can lead to exhaust hose failure allowing gases and hot saltwater to leak into the bilge. ETC.
3) Saltwater leaks (external engine) in general causing engine corrosion.
Besides dealing with this, if your engines have aftercoolers, I strongly suggest servicing them now (after 3 years). Aftercoolers are usually made up of several dissimilar metals, and left sitting in an electrolyte (saltwater) they can act like a battery where the least noble metal will badly corrode (and sometimes quite quickly) leading to potentially very expensive failures and/or the need to replace (the not inexpensive) aftercoolers. Check out sbmar.com for the best procedures for servicing them (under Tony's tips). Even if a "pro" is doing the work, insist he follow these procedures to protect your aftercoolers.
Good luck, and it is easier to keep your engines operating and looking good than it is to correct the issues after the fact
Based on the age of your boat, I would agree with RTF!
However, the raw water cooling system requires regular maintenance if you want to avoid potentially BIG issues. Without this maintenance, a person is relying on good luck and in boating that is not a good path to follow in the long term.
All of these components should be taken off the engine and fully serviced (which includes pressure testing) every 5 (4-5) years at most (unless you regularly freshwater flush your engine's raw water cooling system after use... then the time can be extended for a couple of years or so). Leaving the engine sitting full of saltwater for extended periods (even regular operation using saltwater for cooling) accelerates what can be termed "marine age" which shortens the overall life of the engine. Freshwater flushing is easy, and it works!!!
Issues that can develop without regular maintenance include:
1)Engine overheating. Overheating can lead to severe damage requiring major repairs.
2)Saltwater intrusion into areas you don't want it! Eg. Aftercooler can allow saltwater to enter the air intake. Gear cooler can send saltwater into the tranny or send the tranny oil out the exhaust. HX can send saltwater into the engine coolant (antfreeze). Exhaust elbow leaking internally can send saltwater into the turbo or exhaust side of the engine (in a poorly designed exhaust system - many examples out there in service) or can lead to exhaust hose failure allowing gases and hot saltwater to leak into the bilge. ETC.
3) Saltwater leaks (external engine) in general causing engine corrosion.
Besides dealing with this, if your engines have aftercoolers, I strongly suggest servicing them now (after 3 years). Aftercoolers are usually made up of several dissimilar metals, and left sitting in an electrolyte (saltwater) they can act like a battery where the least noble metal will badly corrode (and sometimes quite quickly) leading to potentially very expensive failures and/or the need to replace (the not inexpensive) aftercoolers. Check out sbmar.com for the best procedures for servicing them (under Tony's tips). Even if a "pro" is doing the work, insist he follow these procedures to protect your aftercoolers.
Good luck, and it is easier to keep your engines operating and looking good than it is to correct the issues after the fact
nhislander
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Not sure if this would help but I have been doing a fresh water flush whenever I anticipate the boat sitting idle for more than a week... Given the sea water strainers are well above the water line on the ST-44 it is simple to:
1 - Remove the strainer cap, insert garden hose and run some fresh water through (note, most of this water just flushes down through the raw water intakes)
2 - Close the raw water intakes
3 - As simultaneously as possible (a 2nd person helps...) start the motor, turn on fresh water flow down through your sea-strainer... and run motor at idle speed for a few minutes
4 - You can also add some salt-away towards the end of your flush process... then shut things down while some of the salt-away is still in your raw-water system...
5 - After this flush process, I also leave my raw water intakes closed when not using my boat to reduce intrusion of salt water after flushing but REMEMBER TO OPEN THESE BEFORE YOU START YOUR MOTORS NEXT TIME... (I put a reminder note on my ignition buttons...).
6 - Note - I do the same process for my generator too...
Do other ST-44 owners regularly do a fresh water flush? Thoughts?
1 - Remove the strainer cap, insert garden hose and run some fresh water through (note, most of this water just flushes down through the raw water intakes)
2 - Close the raw water intakes
3 - As simultaneously as possible (a 2nd person helps...) start the motor, turn on fresh water flow down through your sea-strainer... and run motor at idle speed for a few minutes
4 - You can also add some salt-away towards the end of your flush process... then shut things down while some of the salt-away is still in your raw-water system...
5 - After this flush process, I also leave my raw water intakes closed when not using my boat to reduce intrusion of salt water after flushing but REMEMBER TO OPEN THESE BEFORE YOU START YOUR MOTORS NEXT TIME... (I put a reminder note on my ignition buttons...).
6 - Note - I do the same process for my generator too...
Do other ST-44 owners regularly do a fresh water flush? Thoughts?
firehoser75
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Since you bring up freshwater flushing, and I agree it is a very simple and good thing to save money, and to prolong the time between service internals for your raw water cooling components, protecting against overheats, and in general potentially extending overall engine life.
I have a photo of my simple setup.
It is a garden hose attachment on the sea strainer cover.
1) Attach a dock hose with decent flow to this attachment with the through hull open. Turn water on. The pressure just exits the boat and backflushes your through hull.
2) Start the engine and run at idle for a few minutes (3-5 minuutes).
3) For true freshwater flushing, close the through hull. However, it will still flush with a mostly freshwater mixture if you leave the through hull partially open. Best to use a "stiff" garden hose rather than flexible, as your engine will try to draw more water than this size of hose can provide. This is not a problem, you just need enough water to lubricate the impeller and flush the system (for this very short run time).
4) Shutdown. Do not shut off the engine with the freshwater running (pressurized) and the through hull closed! Either shut down the water and the engine at the same time, or first shut the freshwater then as fast as possible the engine (having a helper makes this easy and boat layout may hamper solo efforts). Running for a few seconds without a water source will not hurt anything. I know, I have done this procedure many times and have not had an impeller show any signs of damage from it.
Freshwater flushing will slow down all of the ravages of saltwater. Corrosion, marine growth, and other types of tube bundle blockages (obviously not impeller bits, anode pieces, etc.).
From start to finish the entire procedure takes less than 10 minutes, and unless your engine(s) are smokers, running an already warm engine at dock for 3 minutes (while flushing) at dock after you are secure should not really bother anyone. I shutdown as soon as the boat is secure at dock, and only restart after the flush is all set up with water flowing to minimize the time running near other boats.
Attachments
A ST44 owner plumbed in FW flush. Connects hose to the city water inlet, which goes to the generator and two engines. Guessing you can only flush one at a time. Cool idea but not sure how long it really saves the hardware?
I'd also be concerned that you have enough water pressure from a garden hose. Some marinas have bad pressure. Last thing you want to do is keep burning up impellers.
firehoser75
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Mystery,
You are correct, you will need a decent flow of water to the engine, but high "pressure" is not needed. The Sea water entering your pump is not "under pressure". Easy to determine, just look at how much water is coming out of the hose. If it is "barely" coming out, then no, don't try it. Also don't use an easily collapsible hose, use a fairly stiff one to better resist your pump's suction. This will maximize the available flow. To ensure you are not damaging your impeller (if you are worried) put your hand on the pump cover while doing the flushing, if it feels hot to the touch, you don't have enough water so either partially open the through hull (still has good FW flushing benefit) or stop the procedure. Unless your impeller is already "damaged or weakened" (in which case it should be changed anyway), the "hand check" will ensure no harm.
To see first hand about FW flushing (without actually doing it), check out Tony Athens website (sbmar.com) and read about first hand accounts in his forums and info under Tony's Tips. Learn about "marine age" and how it slowly (in some cases not so slowly) destroys our cooling systems, and how neglected cooling systems can "badly damage" engines. In case you don't know, Tony is considered by many to be a guru of marine diesel engines and has well over 35 years experience.
While he does sell products on his site (after all this is his profession), he offers lots of free information under Tony's Tips and answers questions directly on the free forums!
I have no affiliation, have not even met the man.... but have benefited from much of this information that he freely supplies, without overly pandering his products.
Freshwater flushing, done regularly, can extend the time needed between full off engine servicing of the raw water cooling components (almost double the interval if done "religiously") because it greatly reduces internal corrosion (mostly caused by the salt water) and slows down the build up of "salt" deposits in the various "tube" (small) passages inside the various HX type of components (aftercooler, gear oil cooler, heat exchanger, etc.)
Freshwater flushing does not remove the need for proper periodic full off engine servicing (including pressure testing to ensure the unit will not leak internally), but it will keep your engine running cooler between servicing, and extend the time between this service, and in effect, save you time and money in the long run.
It's your choice. Spend a few minutes flushing after each trip, or spend time and money servicing or replacing these components more often, also increasing the risk of overheat "problems" when on your trips and away from your regular service providers. I know which path I chose!
You are correct, you will need a decent flow of water to the engine, but high "pressure" is not needed. The Sea water entering your pump is not "under pressure". Easy to determine, just look at how much water is coming out of the hose. If it is "barely" coming out, then no, don't try it. Also don't use an easily collapsible hose, use a fairly stiff one to better resist your pump's suction. This will maximize the available flow. To ensure you are not damaging your impeller (if you are worried) put your hand on the pump cover while doing the flushing, if it feels hot to the touch, you don't have enough water so either partially open the through hull (still has good FW flushing benefit) or stop the procedure. Unless your impeller is already "damaged or weakened" (in which case it should be changed anyway), the "hand check" will ensure no harm.
To see first hand about FW flushing (without actually doing it), check out Tony Athens website (sbmar.com) and read about first hand accounts in his forums and info under Tony's Tips. Learn about "marine age" and how it slowly (in some cases not so slowly) destroys our cooling systems, and how neglected cooling systems can "badly damage" engines. In case you don't know, Tony is considered by many to be a guru of marine diesel engines and has well over 35 years experience.
While he does sell products on his site (after all this is his profession), he offers lots of free information under Tony's Tips and answers questions directly on the free forums!
I have no affiliation, have not even met the man.... but have benefited from much of this information that he freely supplies, without overly pandering his products.
Freshwater flushing, done regularly, can extend the time needed between full off engine servicing of the raw water cooling components (almost double the interval if done "religiously") because it greatly reduces internal corrosion (mostly caused by the salt water) and slows down the build up of "salt" deposits in the various "tube" (small) passages inside the various HX type of components (aftercooler, gear oil cooler, heat exchanger, etc.)
Freshwater flushing does not remove the need for proper periodic full off engine servicing (including pressure testing to ensure the unit will not leak internally), but it will keep your engine running cooler between servicing, and extend the time between this service, and in effect, save you time and money in the long run.
It's your choice. Spend a few minutes flushing after each trip, or spend time and money servicing or replacing these components more often, also increasing the risk of overheat "problems" when on your trips and away from your regular service providers. I know which path I chose!
caseclosed
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I removed the hose and used a wire brush to clean away what appears to be salt deposits
on the port side there is some pitting and erosion of the the cooler body. The starboard side had very little salt deposit .I am wondering if the cooler replacement will be covered under my extended warranty from volvo. Thanks to all who replied with suggestions.
on the port side there is some pitting and erosion of the the cooler body. The starboard side had very little salt deposit .I am wondering if the cooler replacement will be covered under my extended warranty from volvo. Thanks to all who replied with suggestions.
C lectric
Guru
I lightly wire brush any corrosion or debris off the nipple to prevent weeps by the debris holding the hose off the nipple which can provide a leak path.
I also use a light smear of Rectorseal #5, there are other good products. It won't glue the hose to the nipple, just help with the seal.
I also use a light smear of Rectorseal #5, there are other good products. It won't glue the hose to the nipple, just help with the seal.
caseclosed
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Thanks That is exactly what I used to seal the hose to the brass nipple.
Long Island Boater
Member
Two comments:
If cooler has a zinc, check that it’s still adequate.
There appears to an earlier discussion back in 2018 that suggests their might be warranty coverage for an oil cooler is issue. Not sure if it applies to your circumstances but work reviewing below link to see if it offers any useful insight..
https://www.trawlerforum.com/forums/s60/beneteau-st-44-potential-sea-water-intrusion-35913-4.html
Also, I agree with the need to maintain cooling system, including repainting as necessary to minimize surface rust and corrosion.
Good luck!
If cooler has a zinc, check that it’s still adequate.
There appears to an earlier discussion back in 2018 that suggests their might be warranty coverage for an oil cooler is issue. Not sure if it applies to your circumstances but work reviewing below link to see if it offers any useful insight..
https://www.trawlerforum.com/forums/s60/beneteau-st-44-potential-sea-water-intrusion-35913-4.html
Also, I agree with the need to maintain cooling system, including repainting as necessary to minimize surface rust and corrosion.
Good luck!
The cooler looks as if it is powder coated aluminum, which would be really unusual. Can you confirm? If so, it is definitely an expendable item when used with raw water, and should be replaced when corrosion appears. It also looks after market, and I'm wondering if it's designed to be used only with coolant. This is on a Yanmar?
Wire brushes should not be used on aluminum, the wire leaves behind trace metal and the aluminum is anodic to almost every other metal save zinc and magnesium. If it needs to be cleaned use a ScotchBrite pad.
If it's aluminum it's likely poultice corrosion, more on that here https://stevedmarineconsulting.com/understanding-and-preventing-aluminum-corrosion/ The result of water leaking from the hose connection and being trapped under the powder coating in that location. Aluminum is best left uncoated, any coating is purely cosmetic.
Most transmission coolers are copper nickel, which is very corrosion resistant and long lasting. If it needs to be replaced, I'd definitely look for a copper-nickel replacement.
Wire brushes should not be used on aluminum, the wire leaves behind trace metal and the aluminum is anodic to almost every other metal save zinc and magnesium. If it needs to be cleaned use a ScotchBrite pad.
If it's aluminum it's likely poultice corrosion, more on that here https://stevedmarineconsulting.com/understanding-and-preventing-aluminum-corrosion/ The result of water leaking from the hose connection and being trapped under the powder coating in that location. Aluminum is best left uncoated, any coating is purely cosmetic.
Most transmission coolers are copper nickel, which is very corrosion resistant and long lasting. If it needs to be replaced, I'd definitely look for a copper-nickel replacement.
caseclosed
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Follow up. Thankfully Volvo replaced both transmission coolers under warranty.
RT Firefly
Enigma
Greetings,
For those who flush with fresh water after a salt water run. Doesn't this affect the sacrificial anode IF it is of zinc material? I vaguely recall zinc undergoes some sort of oxidation in the presence of fresh water thereby nullifying its sacrificial properties.
For those who flush with fresh water after a salt water run. Doesn't this affect the sacrificial anode IF it is of zinc material? I vaguely recall zinc undergoes some sort of oxidation in the presence of fresh water thereby nullifying its sacrificial properties.
Comodave
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Yes, so go with aluminum anodes and they are good in any water, fresh or salt water.
I never even thought of that! Tons of people flush their engines, its a good question.
Its not always that simple. Boatzincs has a good chart or two.
