QSM 11 - seawater leak

[WFYB]

Trying to locate the source of a seawater leak. Started out looking for the source of loose rust in the bilge / starboard motor. Rust source was so close it could have bit me. Turbo housing was rusted and pitted as shown in photo. I believe this engine has a dry exhaust manifold. That being true the only source could be the raw water hose that feeds the elbow or a bad exhaust elbow. Any one else run into this? Any ideas where to look. So far I can not find a leak at idle or under load.

Another question, does anyone know if the seawater dumps directly into the exhaust or does it run in a jacket. Id love to see a drawing of the raw water side of the exhaust system.

 

[Four Suns]

On page D5 of the "Operation and Maintenance Manual" for the QSM11 there is an exploded view of the raw water circuit.

The turbo should not see any sea water internally (or externally).

The last part in the QSM11 diagram is the transmission cooler and you can see it here under the turbo:

From there, the raw water goes into a black hose and up to a stainless manifold that mixes the sea water with the exhaust. You can see the hose connection on the far left of this picture:

It looks like you have a white residue on top of the turbo. Is that salt?

Anyway... there are several places to look for a raw water leak. The raw water system is under a lot of pressure under load and you may be getting a mist you can't see.

In that transmission cooler, those blue lines coming out of the top have transmission oil circulating through them. However, the one circled in red in this picture is a connection that is under pressure that feeds the dripless shaft seals with sea water.

I had that hose fitting develop a leak as shown here:

That hose is $70.00 if you need it in an emergency in Rhode Island (home of all the "cool mods") or only $7.00 if you get it from a local hydraulic shop. Do not over tighten it or it will leak... That's how I know it only costs $7.00 the second time. I would check that hose as it can spray salt water everywhere back there and up into the turbo area you are pointing to. Those lines should only be snugged on and if you overtighten them, they will leak.

I would also check the joint where the transmission cooler slides into the coolant heat exchanger:

I had that rubber o-ring go south after I pulled the transmission heat exchanger and it was all gooped up. Before I could get that thing to seal again, I had to polish the inside of the housing:

with 800 grit wet/dry sand paper and clean the groove the o-ring sets in on the cooler:

and the old o-ring had all kinds of crap on it:

You really can't reuse the old o-rings and they get compressed or something and loose their seal. You can get the part number out of your QSM11 parts book:

These things are like $1.50 each so get a couple extra and throw in your spares box. I got all the rubber o-rings for the whole cooling circuit and carry them as spares... just in case I have to pick impeller pieces out of the thing while out somewhere.

You'll notice that on the bracket on the bottom of that transmission cooler there is rust. That was not where the leak was though... it was just the first thing that would rust with the water running on it. The leak on mine was so small you could never really see it but it would get wet from the very very small leak under high pressure. It's all painted and pretty again... FYI... You may be getting spray up on the turbo and the oil line connection is rusting. You may need to check that out if it is damaged. I would also pull off the air cleaner and make sure your turbo spins freely and is not pitted and the play in the shaft is within spec. If you have had a raw water leak in this area, you are sucking it into the air intake/air cleaner.

I would change the oil and get the oil tested as well.... And clean the air filter... or get a new one...

The other obvious places to look are the black hose connections coming out of the transmission cooler and connecting to the exhaust...

Hope that helps.

 

[Four Suns]

Your boat is approaching the age you need to think about doing a raw water system flush as well... You may want to read this thread and check out the fuel coolers on my QSM11's and the condition they were in:

http://clubsearay.com/forum/showthread.php?t=9487&highlight=coolers

As your boat gets older, you will become very familiar with the raw water cooling system...

 

[WFYB]

Thanks Gary, I am at the boat working, (taking a nap), had a look at the hose that delivers water to the dripless shaft. Port - non leaking - looks nice and clean. Starboard- leaking- looks like the hose in your picture. Green and corroded. I bet that is it.

Yes the material on top of the turbo is salt. And yes I am concerned that I have been drinking air laced with salt. Not much I can do about that at this point but get rid of the leak, check the turbo and change the oil as suggested.

Thanks again for excellent help.

 

[Four Suns]

And now you have to buy a copy of my book when it is released:

(How's that for shameless book pimping?)

 

[WFYB]

Sign me up for one copy. I enjoyed reading your log this summer. I bet the book is a great read.

Thanks again, I'll let you know how this progresses.

 

[jitts3]

Gary,
Any chance you could get another shot of the cooling system page in your service manual. I'm very curious on how those diesel boats operate. Im lost however on those 2 manifolds. #7 #8 and #5. The bottom of the page was chopped off. Just trying to learn more about them. I have a C-16 CAT in a Peterbilt and have always been impresed in the way a large Diesel Operates.

FWI My Ex wife's Uncle had a fishing boat with a set of I believe 8V92 Detroit Diesels. Not 100% on the 92 part but for sure a pair of V8 2 strokes. Was cool as hell to see.

Thanks
Steve

 

[Four Suns]

#5 is the aftercooler for the turbo/intake air
#7 is the heat exchanger for the engine coolant
#8 is the engine coolant reservoir. After the coolant cycles through the engine, it's dumped in the top of that thing and then is pulled through the bottom through the heat exchanger and into the engine.

The raw water cooling system on the QSM11 basically has four heat exchangers and the circuit goes as follows:

Through hull -> strainer -> fuel cooler -> raw water pump/impeller -> turbo/air intake after cooler -> coolant heat exchanger -> transmission cooler -> exhaust elbow -> water lift muffler -> exhaust exit

At cruise, about 120 gallons of sea water are pumped through the system every minute for each engine.

 

[mistercomputerman]

And now you have to buy a copy of my book when it is released:

(How's that for shameless book pimping?)

I thought everyone here had already signed up for your book!

 

[jitts3]

#5 is the aftercooler for the turbo/intake air
#7 is the heat exchanger for the engine coolant
#8 is the engine coolant reservoir. After the coolant cycles through the engine, it's dumped in the top of that thing and then is pulled through the bottom through the heat exchanger and into the engine.

The raw water cooling system on the QSM11 basically has four heat exchangers and the circuit goes as follows:

Through hull -> strainer -> fuel cooler -> raw water pump/impeller -> turbo/air intake after cooler -> coolant heat exchanger -> transmission cooler -> exhaust elbow -> water lift muffler -> exhaust exit

At cruise, about 120 gallons of sea water are pumped through the system every minute for each engine.

Got it...Thanks. Amazed by the engineering that goes into those.
Not sure why but I never expected those to be aftercooled...Guess I was looking for a "air to air" like I have. Thanks again.

 

[WFYB]

Gary, where did you purchase your manual?

 

[Four Suns]

The Operation and Maintenance Manual came with the boat along with a Cummins Captain's Briefing notebook. The parts manual I bought from the parts counter at Cummins Atlantic. The parts manual is great because it has blow-ups of all the systems.

 

[Greg]

I have a leak between the coolant reservoir and the trans cooler on the port engine, it must be a very fine mist. I think this may have happened since this cooler blew off one time and almost sunk the boat. I kept feeling a salt coating in the area, and got higher sodium levels in the oil, but it was always dry.

I zip-tied a towel around the joint, and it is wet when I go down right after a run. I keep the towel there now just to prevent the misting and ingesting, but I have tried many times to cure this.

I have polished the inside of the reservoir, and the groove of the trans cooler, but it still leaks. Always using new o-rings.

I am thinking maybe I need an oversized o-ring.

Any thoughts?