6CTA Low Oil Pressure

[lpmcc]

I have two 6CTA’s in my boat (1999, 2400 hrs).  I just changed the oil 5 hrs ago (Rotella 15w-40, same oil I’ve been using in these engines for 11 years).  Oil pressure is always approx. 50 PSI for both engines (helm gauges).  Yesterday, strb engine went down to 20 PSI (verified with mechanical OP gauge on the engine).   Engine runs as normal, no leaks, etc.  Low oil pressure alarm did not go off.

Since the oil change, the oil in this engine has been “clearer” (more honey color, vs black as in the past, and other engine).  My first thought is something leaking into oil (seawater, coolant, fuel, etc.) and diluting oil.  I’m not losing any coolant, can’t judge the others.  And the oil level has not been rising.  I did an oil & filter change this morning, but the oil pressure is still low.  I have pulled oil samples for testing, but won’t know the results for a few days .

My aftercoolers were pulled and done 6 months ago.  All was in good shape.

Any ideas on what might be going on?  Is there some type of pressure adjuster, spring, etc., that might cause this issue?

Thanks for any help you can provide.

Larry

 

1 user thanked author for this post.

Danny Perna

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[Tony Athens]

What exact oil filter are you using?

[Richard Dodson]

Just a thought, below is a pic out of the C series Cummins book

[lpmcc]

Update.  Oil analysis came back. Sodium was high at 12.3 (last one a few years ago was 6.0). All else was fine, no metals, etc. Swapped all oil senders, mechanical pressure qauges, and pressure regulator. Problem remains at the same engine. Looking at the oil filter housing next.<br /><br />The only other things I can think about are a clogged intake screen on the oil pump or a failing oil pump, but I’ve never heard that. They usually work or don’t<br /><br />Other ideas?<br /><br />Thank for the help.

[Author]

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