Traces of sodium in engine oil

[mark1882]

Hi

I had a chemical analysis done of my engine oil that showed up traces of sodium so any thoughts on the following would be appreciated.

1) Is this likely to be a problem ?

2) Where is the sodium likely to coming from/what is causing it. I assume it is from sea water

3) What would be an acceptable/ok level of sodium in the oil.

4) Is there any other way of telling apart from the chemical panelise of the oil.

I have a Volvo Penta 2003T engine,

Thanks

Mark

 

[JumbleDuck]

Hi

I had a chemical analysis done of my engine oil that showed up traces of sodium so any thoughts on the following would be appreciated.

1) Is this likely to be a problem ?

2) Where is the sodium likely to coming from/what is causing it. I assume it is from sea water

3) What would be an acceptable/ok level of sodium in the oil.

Googling "sodium in engine oil" suggests that it's most likely to be a coolant leak into the oil.

 

[Freebee]

most likely from sea water

 

[VicS]

I agree its almost certainly indicates seawater coolant ingress. I assume it is a raw water cooled engine?

First thing to check is probably the seals on the water pump, then I am afraid the head gasket must be the next suspect if it is directly cooled

But also check the antisyphon system on the cooling water ... but if its got in as result the exhaust system flooding is that likely to have damaged the turbo charger?

Sodium content itself not a cause for great concern its the fact that it is almost certainly due to seawater ingress that is troubling.
A few ppm I think Id not lose too much sleep over. A few X 10 ppm I think needs looking into.

Dont know though what the sodium content of clean engine oil is anyway, if any .

Routine job at one time measuring sodium in heavy fuel oil but never looked at lube oils!

 

[William_H]

OP has fallen into the trap of Spectrum Oil Aanlysis (Program) in thinking one analysis will give a picture of engine health. It does not necessarily do so. If the engine is running fine I would suggest OP does not think about it.
SOAP is useful for high value critical engines where SOAP is performed on a regular basis ie every 100 hrs from new or newly overhauled. The actual elements in the sample is not indicative in itself so much as looking for a trend. So typically lots of lead from new bearings intially then a fairly stable set of results (with oil replaced each time) until imminent catastrophe is indicated by an increase in particular elements in one or more SOAP.
The cost does not make it useful for our kind of pleasure boats. So for the OP if seems to be running OK and oil looks OK (you can tell if there is lots of sea water in it.) Then ignore SOAP results or replace oil and check again and compare end of next season. good luck olewill

 

[vyv_cox]

OP has fallen into the trap of Spectrum Oil Aanlysis (Program) in thinking one analysis will give a picture of engine health. It does not necessarily do so. If the engine is running fine I would suggest OP does not think about it.
SOAP is useful for high value critical engines where SOAP is performed on a regular basis ie every 100 hrs from new or newly overhauled. The actual elements in the sample is not indicative in itself so much as looking for a trend. So typically lots of lead from new bearings intially then a fairly stable set of results (with oil replaced each time) until imminent catastrophe is indicated by an increase in particular elements in one or more SOAP.
The cost does not make it useful for our kind of pleasure boats. So for the OP if seems to be running OK and oil looks OK (you can tell if there is lots of sea water in it.) Then ignore SOAP results or replace oil and check again and compare end of next season. good luck olewill

Exactly right. A snapshot oil analysis tells you almost nothing. In industrial equipment a programme is set up to take regular samples in order to trend results, which can be useful. But even the sampling technique can introduce contaminants and produce spurious results.

 

[ribrage]

I sample our work boat engines on a routine basis - the only way we would do anything about a bad analysis is an EXTREME result - if ain't broke ,don't fix it !

 

[Ruffles]

Exactly right. A snapshot oil analysis tells you almost nothing. In industrial equipment a programme is set up to take regular samples in order to trend results, which can be useful. But even the sampling technique can introduce contaminants and produce spurious results.

I guess even the sudden absence of trace elements might indicate problems - oil isn't reaching the bearing!

 

[mattnj]

Hi

I had a chemical analysis done of my engine oil that showed up traces of sodium so any thoughts on the following would be appreciated.

1) Is this likely to be a problem ?

2) Where is the sodium likely to coming from/what is causing it. I assume it is from sea water

3) What would be an acceptable/ok level of sodium in the oil.

4) Is there any other way of telling apart from the chemical panelise of the oil.

I have a Volvo Penta 2003T engine,

Thanks

Mark

the 2003T is freshwater cooled, but it has an oil cooler behind the main heat exchanger (neglected part) which is raw water cooled (i think)
I was worried about mine when I had one a bout 5 years ago, and decided to take it all off, not really a big job, took about an hour or so to get it apart, from memory you have to take starter off first, then the heat exchanger then the oil cooler, they are known to leak/fail, get that off for investigation, mine was in a shocking state behind there, but all cleaned up ok with new seals etc.

I was going to replace with an oil/water oil cooler of filter housing type cooler, but no need in the end.

 

[mattnj]

See here for the oil cooler

http://www.ybw.com/forums/showthread.php?260745-Replacement-for-Volvo-Penta-2003

 

[vyv_cox]

Googling "sodium in engine oil" suggests that it's most likely to be a coolant leak into the oil.

Very many years ago I used to make up antifreeze mixtures for lab personnel use, courtesy my employer. In addition to ethylene glycol it contained sodium nitrite as a corrosion inhibitor and sodium benzoate, I no longer remember why. I don't suppose the contents are much different now.