It worked ... was it supposed to?

[Kurlie1]

Thanks A64.
You make good sense.
My next challenge will be to remove the core. Access to the heat exchanger and having the correct equipment (seals and 'O rings etc) are the concerns.
When the madness abates I have work to do.
Cheers

[Sailmonkey]

Our heat exchanger was designed by someone who didn’t understand margin. So I’ve got to pull our tube bundle every year or two for a deep cleaning, but I do the CLR flush 2-3 times between between pulling the tubes. So far over 13 years of ownership there has been no noticeable degradation of the material.

[khoff]

Please disregard my post , I was thinking of a water cooled exhaust manifold , I was in the right pew but the wrong church !

[Bawlmer]

Originally Posted by 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!

You beat me to it. My little 2 cylinder Westerbeke empties a 2 gallon bucket in way less than a minute. There is definitely a flow problem.

[FPNC]

The product that you used is acid. As is RydLyme, Muriatic acid and vinegar. All of which in various degrees of concentration, can be used to clean a bronze heat exchanger core that has been removed from the engine. Aluminum does not get along well with acid so you want to keep the stronger acids away from any aluminum parts.

Your cleaning may have removed mineral buildup from the salt water side of the system but it did not clean the coolant side of the system. Also, the acid will not remove blockages from plant and animal parts or stray pieces of impeller rubber. To get the best heat transfer it would be best to pull the core for a complete cleaning.

[Cheechako]

You might want to get a hand held non contact thermometer, they aren't very expensive now. I tried to solve an overheating issue for about a third of the return trip to the US from Trinidad. After a couple weeks we finally figured out the temp sensor was bad and the engine wasn't overheating at all!

[Kurlie1]

Thanks for your ideas all.
The motor looks farely cluttered. It might be a challenge getting to the heat exchanger - I can't even see it.

[chrisr]

Originally Posted by Cheechako

You might want to get a hand held non contact thermometer, they aren't very expensive now. I tried to solve an overheating issue for about a third of the return trip to the US from Trinidad. After a couple weeks we finally figured out the temp sensor was bad and the engine wasn't overheating at all!

that sounds like a good suggestion - although i always feel steam in the exhaust water is a give-away too !

but seriously, this question of inaccurate temp gauge is one reason why i often stick my hand in the out-put exhaust water. you can quite quite use to the feel of the temp, and pick up any changes

cheers,

[Capt Ben]

When I had overheating issues w/my (now replaced) 2003 I found the main culprit was the mixing exhaust elbow. A friend suggested I try blowing through the part that mixes the water in to see if there was any restriction. There was. I tried rodding it, a mix of muriatic acid, etc. None worked well enough. Eventually, I bought a stainless steel version, available on line. Wow, what a difference that made. I thought I had good water flow beforehand, but nothing like the flow after changing the elbow. BTW, cleaning the HX is not difficult. I removed, bathed mine in a diluted muriatic acid, and scoured the tubes with a bottle brush. I believe 22 gauge gun cleaning brushes are considered ideal.

[DougR]

Originally Posted by Kurlie1

Thanks A64.
You make good sense.
My next challenge will be to remove the core. Access to the heat exchanger and having the correct equipment (seals and 'O rings etc) are the concerns.
When the madness abates I have work to do.
Cheers

Your HE doesn’t have a removable core. It is a one piece copper/brass unit with removable end caps. If you remove the end caps you can “rod” out the tubes from one end to the other with a suitable brazing rod or similar. Do have on hand O rings for the end caps, for the threaded rod that secures the end caps, and for the copper seawater pipes that carry the sea water to and from the HE. As mentioned, the sea water flow travels to the exhaust elbow after the HE, and this could be a source of flow restriction as well. The cast stainless elbow mentioned by Capt Ben for your engine is available from a company called HDI Marine. They are on the west coast of the US and you can find them online.

Also consider the condition of your sea water pump.....it could be marginal as well.

Here are the sea water pump flows in liters/minute as taken from the technical data sheet for the 2003 engine:

1500rpm.......8 liters
2000rpm.......12 liters
2500rpm.......16 liters
3000rpm.......18 liters
3200rpm.......20 liters

DougR

[Cheechako]

Originally Posted by Kurlie1

Thanks for your ideas all.
The motor looks farely cluttered. It might be a challenge getting to the heat exchanger - I can't even see it.

I dont see a heat exchanger.....?

[DeValency]

Sounds like you did exactly the right thing.

I had an overheating problem with a TMD31 Volvo Penta (100HP turbo) I bought a year ago, got overheating at over 2000RPM. The former owner didn’t care too much as the boat got to hull speed at calm sea already at 1600 with the way overpowered (original) beast. Had to open the heat exchanger flange, clean with a brass brush 3/4 of the heavily clogged tubes, replace rubber seals and replace the flange back - fully tighten in place - that’s critical and quite difficult!

At that point circulated “Barnacle Buster” mixed in a gallon of fresh water through the raw water hot level system for an hour and the same through fresh water (coolant) system - just in case and washed out with fresh water and finally coolant.

That’s it. Can run the beast to 3,500RPM without any problem. It was important at some extremely heavy seas situations.

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

[cjheath]

I had an overheating problem crop up on my older Volvo not too long after I bought my boat and pulled out the heat exchanger and it was fine. Actually I pulled out everything... the impeller, the thermostat the works but they were all fine. The problem ended up being the hardest part to get to: the gearbox cooler ( that’s why it hadn’t been serviced in ages ( ever?) after cleaning all the necessary bits and reassembling it was all fine however I did also fit one of these...

https://engineguard.com.au/?gclid=Cj...YaAn6yEALw_wcB

I’m not associated with this company in anyway apart from living in the same country (AUS) but I must say it’s been brilliant. For some reason most of their marketing is aimed at car owners but I think it’s the best AUD$100 you’ll ever spend on your boat. Super easy to install and gives you a digital display of your engine running temp with a warning alarm long before you’re in serious trouble. You can set it to warn you long before the Volvo ( yanmar.. whatever) alarm goes off. Highly recommend this particularly if you’re not strong on engines and technical things (and perhaps a bit slack doing your own maintenance !) I recommend them to all my boat owning friends. Edit: oh shoot... forgot to mention that mine is in degrees C and I’m not sure if there is a degrees F option but it will still do the same job; protect your engine!

[deblen]

Link to 2003 parts diagrams Volvo Penta Schematics - Marine Parts Express


I have a 2003 & have had most of it apart.
Suggest you check the water temp sender & thermostat with boiling water first.

https://avdhoeff.home.xs4all.nl/zeil...hop-Manual.pdf

Suggest you check the raw water seacock & raw water filter for obstruction second.
Also check the raw water suction hose from seacock to RW pump inlet for collapsing during higher RPM.
Check RW pump cover & rear wall for wear grooving.



Suggest you get new gasket & seal rings,remove the Exhaust elbow & check/clean the raw water passages in elbow next .It is a fairly straightforward job.Clean the elbow passages with screwdriver& hammer & then a good overnight soaking in your choice of de-scaler.



Getting at the HX requires removing alternator,etc. You will need all NEW seal rings for both ends of the 4 copper cooling tubes (order extras).
You will need new end gaskets for the HX.
The HX is all bronze on your 2003 non turbo model.
Look for "rubber chips", from old impellers, stuck in the tubes.
The HX removal & re-install is a real juggling act & test of patience,but not particularly complex.



Strongly suggest you instal a raw water filter in the hose between the raw water pump outlet & the HX inlet,to catch impeller junk in future.

https://forums.ybw.com/index.php?thr...cement.433204/


Cheers/ Len

[Kurlie1]

Thanks everyone. Great info here. Thanks for the links Len. Very usefull. Stay safe everyone