Salt in after cooler

[Hank Ellwood]

 My mechanic is servicing the cooling system on my QSC 540’s.  Boat has 5,300 hours.  I have owned the boat since new and serviced the cooling system regularly every two years.  Service is by the book, complete disassembly, removal of deposits, grease all parts and re assembly with new gaskets.  Engine zincs are replaced at every routine service.

The port after cooler and heat exchanger came apart normally.  There was very little salt and deposits on the core and no visible corrosion.  The starboard one was a different matter.  There was lots of salt and the after cooler was frozen inside the housing.  The mechanic sent it to the machine shop to formulate a mandrel to push it out of the housing.  The heat exchanger came out with a little difficulty.  There was no visible corrosion on it.  I don’t know about corrosion on after cooler since it is at the machine shop.  

Boat runs well, is correctly propped, with no smoke and no visible signs of salt in oil or coolant.  The mechanic is replacing a turbo gasket that leaks a little coolant and will inspect the turbo blades for salt corrosion at that time.

The mechanic doesn’t know why there is so much salt.  I want to get to the bottom of it and be proactive to protect my engine.  Ideas?    

Topic

[Hank Ellwood]

Here are photos showing air cleaners.  Picture is under exposed but there is no rust on the air cleaners.  They were replaced three years ago, no special reason as the originals were in good shape.  I ordered a full kit from Walker Air Sep not knowing I could just order the mist filters.

There is a photo of air vent on starboard side.  It is bone stock and has never been damaged.

I took a couple of photos of inside the engine room from up above.  Better photos could have been taken inside but the mechanic has removed the ladder I climbed in I might have to stay there until he replaced it.   Motor mounts have been repainted once.

One of the photos shows the auto pilot pump behind the starboard start batteries.  I repainted this last year as it was corroded.  We investigated the source of salt water and concluded it has to have been the engine air vent.  There is no other possible source.  There was corrosion on the port side on wiring buss for the bonding system in approximately the same place. 

I believe the soot on the turbo blades intake side is due to the fact I have been running the boat at displacement speed “off the turbo” recently as I am using as much fuel as possible as the boat will be hauled out and bottom painted when repairs are completed. 

I feel like I am getting good advice from mechanics who work on Sunday rather than recreate. 

 

 

 

 

[Rob Schepis]

Engine Room Vents

Not sure what you have for engine room vents and if they are hullside or inboard?  I’ve seen some dorade boxes with broken deflectors and broken collector boxes allowing more than just air to make it’s way in under the right conditions.. 

[Tony Athens]

Salt water mist thru the intake

It’s 100% obvious you are or were eating saltwater /mist  thru the intake/air cleaner.. Have air vent near by? Leaky hatch ??

Take off the air housing and clean everything that looks like rust, add a very light coat of oil/grease to those areas  and reassemble.. Inspect in a few months.. Nothing there should look like rust or corrosion unless the intake in sucking in small amounts of salt water laden air.. 

 

Tony

[Hank Ellwood]

More fotos

[Hank Ellwood]

Mechanic showed up today.  He said the machine shop could not find the leak in the after cooler.  No matter, a new one will arrive Tuesday.

We removed the turbo as it was necessary to replace the coolant gasket as well as inspect it for any salt water intake damage. 

Here are photos in low resolution for posting.  There is an exhaust leak so the gasket will be replaced as well as the surface smoothed as there is a tiny bit of warping.  Everything else looked fine with zero evidence of any salt water intrusion on the intake side of the turbo and the intake side of the engine.  Thank you for your help.

[Rob Schepis]

Yeah, your vintage is clear. If cold start is easy and crankcase bypass is normal then likely nothing to worry about.  An oil sample review of the sodium levels will indicate what was coming through and then you can also review the wear metals between the two engines.

[Hank Ellwood]

Engines are 2007, QSC’s go back to 2005.  I’ll post fotos if the mechanic ever shows up to finish the job.  The idea is have the machine shop find the new leak and patch the after cooler core.  The old core will be installed only until I can drive up to U.S. and pick up the new after cooler.  My concern at this point is whether I have engine damage.   

[Rob Schepis]

Yeah, ouch, even if it was $3200 installed it would still be an ouch but $3200 on your doorstep hurts even more.

BTW, what year are your QSC540’s? Very early models had a preproduction airtube set up on the aftercoolers which would render replacement with the new aftercoolers not plug and play…but adaptable.

If you get around to posting those photos Tony requested then that would answer it or maybe you already had this conversation with Brad.

[Hank Ellwood]

Here is an update.  Pressure test revealed leaks in two after cooler tubes.  They were plugged off by the machine shop.  After cooler was assembled and whole assembly was pressure tested at 20 pounds.  Pressure dropped after 4 minutes or so and mechanic could hear air leaking some where inside.  I ordered a new after cooler assembly from Brad, $3,200 ouch, wish Cummins would just sell the cores.

I haven’t yet inspected turbo blades.  Boost was normal just prior to service. 

 

 

[Rob Schepis]

Right, upstream is where things would be originating….The air intake of the turbo is basically a big vacuum cleaner that is sucking in the engine room “environment” so if there is a salt air issue in the engine room (problem with engine room vent, misting seawater hose, etc) it would be the turbo that was sucking it in and feeding it to the aftercooler, thus the air side/fins of the turbo would show some level of salt contamination.

[Hank Ellwood]

My mechanic had the after cooler core pressure tested.  I will have the results today.  If there is a pin hole leak, it will be repaired, by soldering. 

I am nervous.  If there is one leak, the tube walls are likely thin and there will be others.  Do you recommend replacing both cores?

I did not see the side of the core as it was stuck inside the housing.  There was lots of salt on the end.

I will take pictures of the turbo blades.  They are upstream from the cores, will they show damage?    

I will take pictures of the engine room.  The captain and the mechanic take pride in keeping it ship shape, but it is a mess now as everything is disassembled.

Thank you for helping me to get to the bottom of this. 

 

[Tony Athens]

I am assuming you mean you saw salt on the air side (fins) of the aftercooler, but do not suspect a leak across the o-rings nor the core itself has breached a tube……Then,  the only other way is thru the turbo intake.. How about some real good pics inside the housing of the aluminum fins of the turbine,  and the machined surface of the aluminum compressor air housing  intake surface?? That may tell a story.. Got some pics of the engine as installed from all around?  My eyes miss very little if the pics are good, meaning clear & in-focus)….Sending direct is always better after posting here. Tony      

[Hank Ellwood]

Never pressure tested. 

[Rob Schepis]

When was the last time the aftercooler cores were pressure tested?  How about pressure testing the complete unit on last servicing?

 

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