MD22L exhaust elbow check it!

[Jam]

Thought this may be of interest.  Had few hoses come off engine, thought it may have been due to moving engine whilst replacing sail drive gaiter.  Eventually pipe ruptured with a surprising amount of sea water in engine compartment and bilges.....got back home just!!! This was last season, boat was used little by last owner and not well maintained.  Check your elbow!!!! See pics, surprised engine ran with water out of the exhaust at all.  Pressure must have been huge....all fixed end of last season. Was on to do list but not soon enough!!!
John
(Sorry if posted in wrong place in forum)

[Salty]

..........Eventually pipe ruptured with a surprising amount of sea water in engine compartment and bilges.....

That's the kind of excitement we can all do without John, but in regard to the quantity of water in the engine compartment, this will be pretty much in direct proportion to the length of time between that when the pipe burst, it being discovered, and the engine being stopped, or seizing up. Unfortunately the sea water cooling pump would have continued to pump sea water through the system and out into the engine compartment until that happened and you let out some four letter word like "Oops"

[Lyra]

Exhaust mixing elbow clogging is very common - the question is not "will it happen" but "how soon will it happen" an this obviously depends on engine use. I noticed the problem when the engine simply could not rev up under load. Since then I dismantle, inspect and clean every 2 years or so.

[Sadlerfin]

Mine clogged up last season, engine was little used but 8 years old stopped watering on route to Brighton.

Engineer suggested engine had run at too low reves for too long.

[Jam]

Yeh it was all a bit too exciting.  I feel that the boat was used very little by previous owner and batteries were likely charged in marina by running engine at low revs which may not have helped.  There was no proper battery charging unit on boat and believe it or not the pan holders were in original packing with instructions in the oven unopened ....on a boat built 2000.

[s/y Susanne]

What this clearly illustrates is that the choice of raw cast iron for handling sea water is a poor one and it is almost a guarantee of failure at some time. The end result being either a load of sea-water in your boat, a load of sea water in your exhaust manifold or, as in my case, a potential for a hull-full of poisonous exhaust gases.

Annual inspection of this component would seem to me to be a much greater priority than almost any other routine maintenance.

Be warned!

[Salty]

........and a potential for a hull-full of poisonous exhaust gases.

Annual inspection of this component would seem to me to be a much greater priority than almost any other routine maintenance.

Be warned!

And fit a carbon monoxide detector and alarm. The one I've fitted in addition to providing a very audible alarm, it also notes the level of CO in parts per million. Do be aware though that there are other gasses that can also confuse and trigger the alarm, such as, for example, hydrogen being given off from lead acid batteries being charged. Hydrogen while being flammable, is not poisonous, but should not be ignored, also the level at which hydrogen will trigger an apparent carbon monoxide alarm is considerably lower than will cause your flammable gas detector to go into alarm.

[Mirror45184]

Needed to replace after 6 years. Yes it is a sacrificial part. There is a stainless steel one available from US. Look in Ebay for the supplier. The stainless steel option is only worthwhile if you are prepared to soak and remove the carbon build up at regular intervals.
Cheers

[Impavidus]

Needed to replace after 6 years. Yes it is a sacrificial part. There is a stainless steel one available from US. Look in Ebay for the supplier. The stainless steel option is only worthwhile if you are prepared to soak and remove the carbon build up at regular intervals.
Cheers

See item 45 on this list. http://www.bavariayacht.info/forum/index.php/topic,1241.msg6896.html#msg6896
Please note that failure to check this item can cause raw water to enter the outlet manifold and the engine via the exhaust valves. The result is catastrophic engine failure caused by water in the oil or hydraulic locking of the piston on the compression stroke.

Ant. 

[Jam]

Well numerous replies to this one.  Hope everyone is suitably terrified to check there exhaust.  Hope others learn from my omission on buying boat, as I said it was on my list but not soon enough.  Luckily engine running fine now........although I will touch wood!!😊😊

[DT]

Hi all

Just a few notes from having replaced the elbow on my B34.

I had been away from the boat for a few months, on my return I noted the exhaust started to steam. The other thing I noted was, as you increase revs the water flow started to decrease and become less regular.
I cleaned the inlet side of the heat exchanger , easy job just gently pry off to leave the rubber O ring type seal intact. It was 1/4 covered in barnacles. Didn't fix the problem.
Getting the exhaust hose off from the elbow. Release clamps from muffler as well so as to be able to freely rotate the hose, you will not be able to just pry it off the elbow.
Changed the exhaust elbow with one off eBay because it was quick, quality is OK , having looked at both, the volvo one is better finished and probably worth the extra 40 %.The Ebay one had rough casting. The water inlet, I had to grind off some material in the opening  with a dremel tool to make it freer flowing and more like the volvo unit. I also polished in internal elbow as it was rough with burrs I thought it would trap carbon.
Pity the little rubber elbow is so tricky to remove as a frequent clean would be good.
Having now cleaned up the old elbow for a look, it could have seen a bit more service as it was only the water inlet that was clogged.
However now the exhaust is pumping more water than I can recall it ever doing.

DT
Soliloquy

[Salty]

Hi all

Just a few notes from having replaced the elbow on my B34.
.

I cleaned the inlet side of the heat exchanger , easy job just gently pry off to leave the rubber O ring type seal intact. It was 1/4 covered in barnacles. Didn't fix the problem.
Getting the exhaust hose off from the elbow. Release clamps from muffler as well so as to be able to freely rotate the hose, you will not be able to just pry it off the elbow.
.
.
Having now cleaned up the old elbow for a look, it could have seen a bit more service as it was only the water inlet that was clogged.
However now the exhaust is pumping more water than I can recall it ever doing.

DT
Soliloquy

Another area to consider is the saildrive waterway. You have already noted the presence of barnacle shells within the entrance to the heat exchanger, and the only way for them to get there is through the saildrive leg, up through the hoses, past the hopeless Volvo water filter that lets anything through it if you don’t take care to replace the filter basket in exactly the right way, then past the water pump until they reach the heat exchanger.
Each winter when the boat is ashore I block up the the water inlets into the saildrive after first ensuring that any remaining sea water has been drained out, and then pour vinegar down the hose from the filter into the saildrive. This gets left for at least twenty four hours before being drained off, and all kinds of crud comes out with the spent vinegar. Doing it every year helps to prevent any remaining residents from setting up a large community !!!

[Yngmar]

Parts4Engines now has a stainless version of the elbow connector part, and also the actual elbow. Ordered the connector this winter but haven't replaced it yet - our elbow was still okay 5 years ago and is due another check soon, but last time just needed cleaning up and some paint. The connector was crumbling just like shown above.

Stainless connector looks good quality. Link: https://www.parts4engines.com/volvo-penta-md22-stainless-steel-exhaust-elbow-connector-kit/

[DT]

H Yngmar

I hadn't  come across that parts supplier, great prices .
Im thinking the same thing . I will run some fresh water thru the system before putting it to bed if Im away for a while, which I am these days working away in Japan, lovely waterways up here, however.
Stainless elbow looks like a really nice solution. I think these engines run pretty hot to comply with euro emissions standards so pretty sensitive to this problem.

DT

[JEN-et-ROSS]

Not just the Elbow to check........
 
My brother's boat (Gibsea 372) with Yanmar 30 hp had a partially clogged elbow.
He knew about it and intended to clear it in the near future but was lulled into complacency as the engine ran fine and didn't overheat....

What he failed to appreciate was the small matter of the very hot nature of the cooling water that did get through.
The first sign of trouble was a sudden dramatic increase in engine noise followed by clouds of hot steam and exhaust fumes issuing from the companionway.

I'm afraid his Vetus Muffler couldn't stand the heat and had melted into a sort of brownish blancmange ....c'est la vie...

[Salty]

Precisely because I was concerned about exhaust temperature issues, and particularly after replacing a corroded Volvo silencer with a cheap plastic replacement, I fitted an exhaust temperature monitor. The sensor for this is located through the wall of the exhaust hose about a foot or so (300mm) downstream from the exhaust injection bend, while the display is located within the panel on the binnacle. It gives great peace of mind knowing and seeing that the cooling water is doing exactly what it is supposed to be doing, and where the display remains in continuous operation all the while the engine is switched on. The display has a user adjustable audible and visual alarm so that it can be set to whatever level the user chooses within the range of the instrument.

[sy_Anniina]

Motivated by this thread I checked mine, that looked outside like it never has been inspected. Being a 2001 vintage elbow, I suspected severe clogging.

By luck or low salinity of the Baltic sea, waterways and exhaust route were apprx 80-70% open, only partially blocked by carbon and rust. Some citric acid (could not source HCl..) and the elbow looks like good for the next 10 yrs. Managed to remove most of the rust/carbon deposits, now the channels seem about 95% open.

Additional note for hint on anyone reading this for advice: On our boat you have to dismount the exhaust tube from silencer first to be able to manouver the tube from the elbow. Gasket picks and wd-40 are useful when removing thick tubes that have sat on their mounts for ages.

[Brian]

I ended up with a very expensive repair last year when the exhaust elbow on my D2-55 failed.  When the elbow was taken off I found that it’s seating on the heat exchanger/ exhaust manifold was also corroded, badly enough to need a new heat exchanger unit.  It was interesting that the new exhaust elbow was 50% heavier than the one it replaced.
Checking the elbow regularly might have saved me a great deal of money, and down time waiting on spares to be shipped to Greece.

[semaphore]

Parts4Engines now has a stainless version of the elbow connector part, and also the actual elbow. Ordered the connector this winter but haven't replaced it yet - our elbow was still okay 5 years ago and is due another check soon, but last time just needed cleaning up and some paint. The connector was crumbling just like shown above.

Stainless connector looks good quality. Link: https://www.parts4engines.com/volvo-penta-md22-stainless-steel-exhaust-elbow-connector-kit/

Ours has rust marks on the outside.
I was going to order one made in the pacific northwest: https://hdimarine.net/product/707/