It worked ... was it supposed to?

[Kurlie1]

Hi all. I sail a 1986 Beneteau Idylle 1050 with a Volvo 2003 28hp fresh water cooled diesel inboard.
My mechanical knowledge is what I would call "basic"

Recently I set out for a 3 day cruise in wind-less conditions. (pre COVID) I was running the motor at about 2000rpm. After only about 1 hour out the overheating alarm sounded. I immediately checked the waterflow out of the exhaust ... ok.
Turned off the motor ... Checked seacocks, coolant levels, impeller, hose connections etc.
1 hour of drifting later I started the motor up again. All seemed ok for about another 30 min when the alarm started again
Rechecked everything - This boat is relatively new to me. - Same result.


Long story short I began to doubt The heat exchanger flow.
I rigged up a plastic bottle to the water pump and filled it with a CLR 50:50 solution (see attached pik) started motor and watched the solution get sucke into the motor. As soon as most of the bottle had dissapeared (approx 5min run) I turned off and waited 30 minutes. The refilled the bottle and repeated another 6 times until I had used up 4ltrs of solution.

I noticed a lot of froth and gunge coming out of the exhaust each time.


4 hours of drifting later I started up intending to motor into a nearby island bay for the evening/night. As I motored over I pushed the revs up to 2500 to test the system. NO ALARM!


I decided to push on through the night.
Motoring all night and occaisionally pushing revs up I had no further problems. In fact all seemed sweet for the next several days of cruising and have had no trouble sinc.


Question: Is this "cleansing" system acceptable/recommended method of clearing calcium buildup from the heat exchanger tubes?
Any thoughts appreciated

[mlydon]

I’ve read of it before, and did it on a raw water cooled Volvo. No issues, and I think you’re just fine.

Matt

[chrisr]

it obviously worked this time however might not always

we have just had to overhaul heat exchanger on one of our yanmar 4JH2TE. the heat exchanger was 75% blocked with bits of rubber from disintegrated water pump impellers (past owner)

no flushing would have helped if your problem had been similar...

cheers,

[redneckrob]

Originally Posted by Kurlie1

Hi all. I sail a 1986 Beneteau Idylle 1050 with a Volvo 2003 28hp fresh water cooled diesel inboard.
My mechanical knowledge is what I would call "basic"

Recently I set out for a 3 day cruise in wind-less conditions. (pre COVID) I was running the motor at about 2000rpm. After only about 1 hour out the overheating alarm sounded. I immediately checked the waterflow out of the exhaust ... ok.
Turned off the motor ... Checked seacocks, coolant levels, impeller, hose connections etc.
1 hour of drifting later I started the motor up again. All seemed ok for about another 30 min when the alarm started again
Rechecked everything - This boat is relatively new to me. - Same result.


Long story short I began to doubt The heat exchanger flow.
I rigged up a plastic bottle to the water pump and filled it with a CLR 50:50 solution (see attached pik) started motor and watched the solution get sucke into the motor. As soon as most of the bottle had dissapeared (approx 5min run) I turned off and waited 30 minutes. The refilled the bottle and repeated another 6 times until I had used up 4ltrs of solution.

I noticed a lot of froth and gunge coming out of the exhaust each time.


4 hours of drifting later I started up intending to motor into a nearby island bay for the evening/night. As I motored over I pushed the revs up to 2500 to test the system. NO ALARM!


I decided to push on through the night.
Motoring all night and occaisionally pushing revs up I had no further problems. In fact all seemed sweet for the next several days of cruising and have had no trouble sinc.


Question: Is this "cleansing" system acceptable/recommended method of clearing calcium buildup from the heat exchanger tubes?
Any thoughts appreciated

I've got the newer version of the Volvo Penta 30 HP, the D1-30s. When I use that same technique to pull antifreeze through the system to winterize it takes approximately 20 seconds to suck down an entire 1 gallon container. If it took 5 minutes for yours, assuming I'm understanding what you did (took the seawater intake off the seacock and stuck it down the container?) and there's no huge difference in the water flow in our engines then it sounds like you're not sucking anywhere near enough water through the system. You might want to test the flow rate again, it's possible you got rid of just enough gunk to avoid the alarm but it will clog up again soon.

[khoff]

This may be your "warning" about the heat exchanger ! Often times when the rust and scale build up and clog a good flushing and "rodding out" with a coat hanger will make it useful again , but consider this -the rust in the heat exchanger may be the wall of the exchanger - at some point it may erode away enough to allow water into the engine, I have seen people remove and clean them numerous times , I have also seen one "blow-out" with no warning causing engine destruction . Good Luck and happy sailing

[donradcliffe]

Originally Posted by khoff

This may be your "warning" about the heat exchanger ! Often times when the rust and scale build up and clog a good flushing and "rodding out" with a coat hanger will make it useful again , but consider this -the rust in the heat exchanger may be the wall of the exchanger - at some point it may erode away enough to allow water into the engine, I have seen people remove and clean them numerous times , I have also seen one "blow-out" with no warning causing engine destruction . Good Luck and happy sailing

Heat exchanger tubesheets have coolant on one side and raw water on the other. If a tube fails, the coolant is normally at higher pressure due to the coolant pressure cap, so it leaks through the holes in the tubes and causes the engine to overheat due to low coolant level. The leaks start as pinholes and gradually get bigger. It is not engine destruction without warning unless you ignore the overheating and the loss of coolant.

[KadeyKrogen38]

A product called Barnacle Buster, sold in marine stores is made for this application. It is bio degradable and safe for marine engines. You did the correct thing.

[Exctyengr]

Suggest that you pull the heat exchanger and have it cleaned, inspected and repaired as necessary.

[kenbo]

As previous posters have stated you may have solved it or not. It does seem like your raw water flow is too low if it took more than 30 seconds to empty that 1.5 liter bottle. So I'd look at water flow issues first.

Close the RW seacock and remove the hose from the RW strainer. If the hose is long enough to go above the waterline, great, rod out the seacock with a length of tubing or rod. Perhaps the through hull is blocked by growth.

Check and clean the RW strainer.

Remove the cover from the RW pump and check the impeller for missing vanes or simply replace the impeller. Also make sure that the cam plate is in place and the scoring on the inside of the cover and pump body is minimal.

Check that the coolant is full and clean and if you can, pressure test the coolant side of the system. The pressure test will show any leaks in the heat exchanger tube stack as well as any other leaks.

Inspect the mixing elbow for corrosion blockage by removing the RW inlet hose and rodding the passage out with a welding rod or similar.

If all the above checks out well then the best way to clean the RW side without disassembling the heat exchanger is this. Buy 2 gallons of either Barnacle Buster or Rydlyme, a small bilge pump where the outlet matches your hose size for the RW pump and a five gallon bucket. Disconnect the RW discharge hose from the exhaust mixing elbow or riser and route that as your return to the bucket with the Rydlyme. So you've created a closed loop for the RW side of the cooling system. Remove the RW pump impeller and reinstall the cover. It's a good idea to slip a nylon panty hose over the bilge pump to keep the crud from going back into the heat exchanger. Start the small bilge pump without the engine running and let the Rydlyme circulate through the system for an hour or so. This will clean the system of most everything except impeller vanes and broken anodes. Of course this method does nothing for the exhaust mixing elbow.

Good luck!

[Cadence]

Originally Posted by Kurlie1

Hi all. I sail a 1986 Beneteau Idylle 1050 with a Volvo 2003 28hp fresh water cooled diesel inboard.
My mechanical knowledge is what I would call "basic"

Recently I set out for a 3 day cruise in wind-less conditions. (pre COVID) I was running the motor at about 2000rpm. After only about 1 hour out the overheating alarm sounded. I immediately checked the waterflow out of the exhaust ... ok.
Turned off the motor ... Checked seacocks, coolant levels, impeller, hose connections etc.
1 hour of drifting later I started the motor up again. All seemed ok for about another 30 min when the alarm started again
Rechecked everything - This boat is relatively new to me. - Same result.


Long story short I began to doubt The heat exchanger flow.
I rigged up a plastic bottle to the water pump and filled it with a CLR 50:50 solution (see attached pik) started motor and watched the solution get sucke into the motor. As soon as most of the bottle had dissapeared (approx 5min run) I turned off and waited 30 minutes. The refilled the bottle and repeated another 6 times until I had used up 4ltrs of solution.

I noticed a lot of froth and gunge coming out of the exhaust each time.


4 hours of drifting later I started up intending to motor into a nearby island bay for the evening/night. As I motored over I pushed the revs up to 2500 to test the system. NO ALARM!


I decided to push on through the night.
Motoring all night and occaisionally pushing revs up I had no further problems. In fact all seemed sweet for the next several days of cruising and have had no trouble sinc.


Question: Is this "cleansing" system acceptable/recommended method of clearing calcium buildup from the heat exchanger tubes?
Any thoughts appreciated

Sounds like you solved the problem. You might consider having a HE core
aboard in case a pin hole presents itself after a chemical cleansing.

[Idlegreg]

I should say I am no chemist so others will be much better placed to confirm.

But I would suggest you investigate a bit more - I had never heard of CLR and interested in case it was a particularly good descaler I looked it up.

They do list copper, brass and aluminium among materials you should avoid contacting with CLR.

I suspect your heat exchanger might be made of copper and brass - the engine of aluminium ?

Maybe not a problem for a short duration but you may find the technique accelerates corrosion.

[Kurlie1]

Thanks for the replies all.


Yes. Next time I can get to the boat I will check the flow volume again.


I am familiar with the Rydlime flush. I used that system on my last boat with success. This product CLR (although a lot cheaper) does essentially the same work as Rydlime and Barnacle Buster.


I take your point Greg. This is what I heed to know. Won't use this again if it is likely to encourage internal corrosion. I will check this out.



Thanks Kenbo. Most of what you suggest was tried before I used the flush. Will have a look at the mixing elbow.

[Kurlie1]

I have found another CF discussion on this topic.


http://www.cruisersforum.com/forums/...ms-219351.html.


Seems to suggest that it has been tested by Practical Sailor and is safe to use but not as effective as Rydlyme

[jamhass]

For what it's worth:
The HX is a copper tube sheet inside an aluminum case. The two are separated only by the rubber o-rings, and the aluminum tends to disintegrate over time, especially when crud accumulates bridging the gap and making battery. Thus, periodic inspection and maintenance is a good idea.

In the event that the HX needs replacing, parts (if available -- mine was not) are very expensive but it isn't a huge job to replumb the engine for an after-market unit.

Ditto the oil cooler if you have one installed.

[a64pilot]

I dislike chemical cleaning as I believe it to be harmful to the metals.
Either way just cause it’s not overheating doesn’t mean it’s clean, until you disassemble it and clean it it won’t be either.
There should be a rather large margin in a cooling system, meaning that if it’s in perfect condition only say 75% of its capacity is needed of keep the engine cool, this allows significant degradation before an overheat, if it took 100% of it to keep the engine cool, you would be taking the thing apart monthly to keep it spotless. Having a large margin means longer service intervals, so all you know is it’s clean enough to not overheat at 2500 RPM.

Not taking shots at your work at getting it to stop overheating, it worked but your not done yet.