Oil samples - elevated sodium

[Strecker25]

I received our annual oil samples from our mains back today. We boat in fresh water on lake ontario, and these are RWC engines. We are seeing elevated sodium ( 103ppm port and 106ppm stbd) The only place I can think this would come from would be the AF used in winter layup. All risers and manifolds are less than two years old. No trace of water in the oil, and the engines run fine.

Is it possible it's just the oil? I use the Merc 25W-40 non synthetic. Anyone have any samples using that same oil?

 

[Strecker25]

For comparison

Port on 3/23/2015: 135ppm sodium (unknown oil by selling dealership)
Port on 10/25/16: 103ppm (quicksilver 25w-40)

Stbd on 3/23/15: 25ppm (unknown oil by selling dealership)
stbd on 10/25/16: 106ppm (quicksilver 25w-40)

 

[Alumarine]

How many ppm is supposed to be bad?

 

[alldodge]

Could be a few things but the main is salt water. What motors are we discussing, diesel, gas, what size?

 

[Strecker25]

Sorry, should have given more info. They're twin 1998 5.7EFI Mercruisers RWC paired to alpha I Gen II's. The manifolds, risers, and elbows were all done when we bought the boat in March 2015. It is used strictly in fresh water on Lake Ontario, but I do winterize by filling the block with AF.

I've sent a note to the analysis company to find out what they consider bad, Merc has also said they don't offer details on their oil but I sent them to PPM numbers and they will get back to me whether it's way out of range for their oil

 

[alldodge]

Look forward to hearing what the out comes is

 

[Scott Danforth]

was there a rise in viscosity as well as the elevated sodium?

I am assuming your numbers on your port motor are in error, or you started with more sodium than you have now.

sodium could come from condensation burning off as well, or it could be an adative in the oil. coolant usually also leaves potasium.

 

[Strecker25]

Here are the two result sheets. Top is Port, bottom is STBD. The analysis center says 55-65ppm is normal for our engines. Notice it says 25W-50 as the weight, but I wrote 25w-40 on the sheet as the source oil. I asked them if that is a result of a test or if they just typed it in wrong.

 

[alldodge]

Take your pics and upload them instead of linking to another site.

 

[Faztbullet]

Is it sodium borate, sodium silicate or sodium nitrate? These can leech it oil from oil cooler leakage or gasket problems and are in the pink antifreeze