QSC with elevated aluminum in oil sample(s) – Thoughts?

[Kraig Kilger]

Here are the basics.  Would very much appreciate thoughts regarding potential source of the issue and actions (if any) to be taken.  Thank you.

• QSC 540 with 2660 hrs.  
• Elevated aluminum in oil sample a year ago (25ppm).  80 hrs on oil.  Oil changed after sample taken.
• Elevated aluminum this year in oil sample (29ppm).  60 hrs on oil.  Report attached.
•  As shown in attached report, aluminum in prior years was nil
• All other readings appear normal
• Engine runs great and runs below fuel curve – i.e., underpropped
• Engine does not burn oil
• Starts immediately at cold start
• Does not smoke and no transom soot 
• No drop in oil pressure over prior years
• No noticeable blow-by based upon placing hand over oil fill 
• Oil Sample on other engine shows no issues (aluminum at 2ppm)
• Aftercoolers were removed, serviced, and reinstalled about 18 months ago.  Issue started after aftercooler service.  Mechanic does not believe they are related.  Report shows no Na so assuming no indication of saltwater intrusion.       

Topic

[Kraig Kilger]

Clogged AC condensation drain

I removed the condensation drains on both AC’s.  These are the check valve versions that close with a few lbs of pressure.  The drain on the engine with the offending oil sample was clogged and the AC was holding a small amount of fresh water (it has been a few weeks since I ran the boat and I presume there was more water at shut down).  The drain on the other AC worked fine.  I suspect that the AC has been holding water after each run for some time and that this may have caused a bit of aluminum surface corrosion on the inside of the housing, thus resulting in the odd oil sample results.  I cleaned the drains to remove debris, oil, etc… so they move freely and reinstalled.  Will test oil after 15-20 hours and see what we get.  Either way, it’s a good reminder that these valves can get junked up and stop working so occasional inspection and cleaning is prudent.  

[Kraig Kilger]

Tony – I removed the air filters to provide pics for both engines as requests (attached).  Port is the one we have been discussing.  

One data point I neglected to mention because the mechanic said it would not be related to the elevated aluminum readings is that I have recently experienced a small loss of coolant in this same engine when running.  As an example, on a recent 80+ nautical mile weekend the overflow bottle was down about an inch.  No evidence of a coolant leak on the engine or in the bilge that I can find.  I am going to have the system pressure tested.  HX is a possibility or perhaps a turbo-to-manifold gasket (??).  No coolant in the oil per test results.  Could these issues be related?  The timing of overlaps – coincidence?   

Assuming nothing else jumps out, it seems like I may be dealing with aluminum sluffing off of the AC casing.  If so, is this something that I can take care of in the ordinary course over then next 6-9 months while still using the boat given that the AC is not leaking (Na was zero), or would you put it at the top of the to-do list?  

Thank you as always!

[Tony Athens]

Engine loading is  great————————–So based on all you have posted?

You should know the answer……….

Nothing left but the aftercooler assembly via a completely unknown method  and what is going on inside of it. .  It deserves a PROPER look at.. 

OR, (that’s why I wanted a peek inside the turbo inlets)– Salt water dripping on one side causing aluminum corrosion? Not likely but something to look at.        

[Kraig Kilger]

Hey Tony.

• I have owned the boat for almost 7 years.  Prior owner put almost 2000 hrs on the boat.  Rest of the hours are mine.
• GPH at 2000 rpm on this engine is mid-high 13 gph although I never cruise there.  I run around 2200.  At 2200 this engine burns under 17gph.  Typically in the mid/high 16’s depending on load and conditions.  At 80% throttle it is under 65% load.  The other engine (starboard) burns approx. 3% more.  Been that way since I bought the boat regardless of prop adjustments.     
• Mechanic removed aftercoolers, sent to a shop for disassembly, cleaning, and reassembly.  Reinstalled by mechanic.  I did not see them when they were off.  They were purchased new as preventative maintenance a little less than 5 years ago (one from your shop as I recall).  I was thinking this could be from housing corrosion inside the AC (mechanic doesn’t think so).
• FYI, I fresh water flush after each run.    

[Tony Athens]

• Aftercoolers were removed, serviced, and reinstalled about 18 months ago.  Issue started after aftercooler service.  Mechanic does not believe they are related.  Report shows no Na so assuming no indication of saltwater intrusion.       

  Who did the aftercooler service–were you privy to watching the actual service/methods employed? 

  What is your GPH at 2000 RPM for each engine? 

  How long have you had the vessel?- yrs/hours  

How did the engine get to 2600Hours–Certainly not at 60-80/hrs a year?

Any chance I could see inside the turbo INTAKE side  / turbine blades  of each turbo”

 

  Tony

[Author]

Replies