Oil analysis shows coolant in oil Cummins 6BT

[silvermb]

I have a 2005 NP Trawler with twin Cummins 6BT engines. Recent oil analysis (i changed oil in between analysis 1 and 2, and operated 4 hours) came back with high sodium and possible coolant in the oil. There is no milky consistency to the oil, the boat runs well, oil pressure is in range and no exhaust issues. Is it possible this is seawater contamination and not coolant? Is it likely a head gasket or could it be a heat exchanger or oil cooler issue? My engine knowledge is weak and i am hunting for answers before the technician shows up! Thank you!

 

[tiltrider1]

If you know you got the engine extremely hot then I would start with doing a CO test on the heat exchanger. My guess is that you haven’t because you didn’t lead with such a statement.

This leads me to believe you have a leaking oil cooler exchanger. A pressure test on the oil cooler would confirm this.

 

[silvermb]

It has not overheated. I’ll start with the oil cooler. I thought the oil cooler exchanger was water cooled, which is why i thought the sodium might be saltwater. Does that make any sense? There’s not much else out of tolerance on the April oil sample above. Thanks for the response!

 

[tiltrider1]

Many oil heat exchangers use raw water to cool. Some use a coolant loop were the coolant is cooled by raw water. Oil cooler heat exchangers are a common failure point.

 

[O C Diver]

While an oil cooler could explain antifreeze in the oil, I wouldn't expect it to indicate high sodium as the oil cooler is in the antifreeze loop, not the raw water loop.

Were the oil and antifreeze levels normal, higher or lower?

On a 6BT, there's no place where the raw water is separated by a seal from the oil. The raw water pump has a vent and both the oil and raw water have seals that separate them (oil and water) from the vented area.

If you find nothing else, run the engine in neutral at cruise RPM and look for raw water misting near the tubo air intake.

Another thought is to send out a second oil sample with a priority rush. Sometimes mistakes are made.

Ted

 

[RickyD]

Well I clicked on Quote to comment on when water will evaporate. I'm not sure what happened. Water and other liquids have a vapor pressure from evaporation. The higher the temperature the higher the vapor pressure goes and the more it evaporates. Get it good and hot and it will be gone under normal conditions.

 

[silvermb]

Thanks for all the replies. There has been no noticeable fluid level change in oil or coolant. I have done 2 oil samples (posted above), but I’m doing a third with another service (I’ll post it when it’s back). It’s inexpensive, and I’m looking for data points. I’ll start with the oil cooler and work from there. It seems to be a rabbit hole to track down this issue, and I want to go at it in the most sensible path. Any other input is welcome!

 

[SteveK]

Here is where I like the Blackstone reports better. They include a side by side engine type average to relate your numbers to. There is also a summary that interprets the results.

Unless OP has more details to share all this report shows me is there is notifiable coolant (antifreeze) in the mix higher than expected. Sodium as well is highlighted higher than expected.
Antifreeze can contain sodium.
Does this engine oil cooler use raw or antifreeze coolant? IMO less likely a fresh water heat exchanger has failed.
Yes a head gasket may be bleeding enough to be considered. I would start by following a re-torquing of the head especially if that is recommended at intervals'.
Caveat, I do not know this engine, but I did stay at a Holiday Inn express once.

 

[Greg QS]

What was the oil like at oil change 1. Why the testing after only 4 hours. Sounds like you know something is going on. Was there any service done on the engine before these oil changes. Antifreze can leak into oil on some services.

My biggest concern is changing oil in 4 hours time and high sodium count? cummings b engines are aftercooled. Start there, sounds like a salt water ingestion into the engine through the air side. The water burns off in the cylinder and the salt washes down into the oil.

 

[silvermb]

We sampled the oil again after the four hours to see if there was a significant difference from the first sample, which had 140 hours on it. To answer your second question, we actually did a full engine service when we took the first sample (coolant included)). The engine I have (6BT) is not after cooled. The Cummins 6BTA is the after cooled model, I believe.

I’m still trying to figure out whether I should continue to run it and test the oil frequently, or start trying to diagnose the issue with a diesel technitian. Any input is appreciated. Oil samples are in the first post of this string.

 

[Greg QS]

Sodium can come salt water. ( highly likely on aftercooled) But your not.
If you look you sodium and potassium levels are down from the last oil change only 4 hours ago. Potassium comes from the antifreeze not from water ingestion.
I believe in the KISS method of engine diagnosis (keep It simple stupid) Lets not assume the worst.

Give us some background on the engine.
what if any major services have been done to the engine in the recent past?
Any engine overheats?
What are the running temps? are they stable?
Is the turbo coolant cooled or dry/ wrapped in a blanket?
What does the exhaust look and smell like?
what did the oil look like at the first oil test?
Are you having any running problems at all?
Why did you do the first oil sample test?
What was going on before the first oil change?
What exactly was the full engine service ? be specific please
Did you just change the oil and filter?
did you flush the engine oil side?
any oil in the antifreeze in its history? Kind of looks like grease in the fluid

The more info you give , the better we can help.

 

[silvermb]

Answering the questions above. Thanks for asking, Greg QS!
This is the starboard engine on a twin 42 foot north Pacific, 2005.
The only major part that has been changed on the engine is the water pump. The engines have been running perfectly.
No overheats, but the boat is in charter, and was out two weeks last summer and has not had significant time on the water since.
About typically runs 185° to 190°, and is turbo cooled
There’s a little bit of white smoke in the exhaust, but it is pretty clear
There was no significant visual issue with the oil that we took on either test (not milky in any way)
Here’s what was done in the engine service, when we took the oil sample:
Take & submit gear oil sample, Change lubrication oil, Install new lubrication oil filter, Clean Racor bowls, Install new primary fuel filters, Install new secondary fuel filters, Change gear oil, Clean gear screens, Install new impellers, Check belt tension, Install new zincs on all heat exchangers/coolers, Check coolant concentration, Clean air filter, Clean sea strainer, Clean engine sump pan, Check throttle & shift controls, pins & cables at helm, flybridge, & engines; lube, Inspect wiring, wiring harnesses, connections & starter motor for corrosion, chafe & tightness; service as required, Spray electrical components with BOE SHIELD when touch-up paint is dry, Inspect all bolts, nuts, hose clamps & engine fittings; Inspect oil centrifuge and/or bypass filter
No oil in the coolant, and no significant burn of coolant

The boat is running well, and we were ready for a great summer! Hoping we dont find ourselves tearing it down! Thank you for the insights and support!

 

[O C Diver]

Answering the questions above. Thanks for asking, Greg QS!
This is the starboard engine on a twin 42 foot north Pacific, 2005.
The only major part that has been changed on the engine is the water pump. The engines have been running perfectly.
No overheats, but the boat is in charter, and was out two weeks last summer and has not had significant time on the water since.
About typically runs 185° to 190°, and is turbo cooled
There’s a little bit of white smoke in the exhaust, but it is pretty clear
There was no significant visual issue with the oil that we took on either test (not milky in any way)
Here’s what was done in the engine service, when we took the oil sample:
Take & submit gear oil sample, Change lubrication oil, Install new lubrication oil filter, Clean Racor bowls, Install new primary fuel filters, Install new secondary fuel filters, Change gear oil, Clean gear screens, Install new impellers, Check belt tension, Install new zincs on all heat exchangers/coolers, Check coolant concentration, Clean air filter, Clean sea strainer, Clean engine sump pan, Check throttle & shift controls, pins & cables at helm, flybridge, & engines; lube, Inspect wiring, wiring harnesses, connections & starter motor for corrosion, chafe & tightness; service as required, Spray electrical components with BOE SHIELD when touch-up paint is dry, Inspect all bolts, nuts, hose clamps & engine fittings; Inspect oil centrifuge and/or bypass filter
No oil in the coolant, and no significant burn of coolant

The boat is running well, and we were ready for a great summer! Hoping we dont find ourselves tearing it down! Thank you for the insights and support!

While it's statistically extremely unlikely, you might have two problems. You might have a problem with the heat exchanger leaking saltwater into the cooling system and a leak between oil and coolant. Since the heat exchanger is almost 20 years old, I would start with a coolant analysis. Typically a good oil analysis company will do antifreeze as well. I've had mine done at Blackstone Labs. If you choose to do this, indicate that you're looking for high sodium and engine oil traces.

Ted

 

[SteveK]

I have wondered if reduced raw water flow through the heat exchanger on the way into the exhaust flow allows the exhaust to steam the water easier and become visible with nothing yet physically broken. At the same time water temp may have only risen 5*. A sign/precursor to some failure.
This was after doing a raw water impeller change for the season as preventative measure. Maybe imagined less white after.

 

[RickyD]

I have Cat 3208s, different I know, but my port oil cooler leaked and I had black oil floating in my coolant. I didn't have recycle bottles on my engines so I didn't notice it until I stuck my finger in the coolant. Without the bottles the coolant level would just stabilize a bit below the overflow. Much later, also the port engine, I noticed that water level was right at the top of the reservoir. Overflow was going and hiding in the bilge. My coolant bundle had perforated. Crap. Salt water in my coolant. I probably flushed that sucker 15 times to get the salt out and $90 in coolant. So I added the recycle bottles so I can see what is going on better.

 

[sunchaser]

I have Cat 3208s, different I know, but my port oil cooler leaked and I had black oil floating in my coolant. I didn't have recycle bottles on my engines so I didn't notice it until I stuck my finger in the coolant. Without the bottles the coolant level would just stabilize a bit below the overflow. Much later, also the port engine, I noticed that water level was right at the top of the reservoir. Overflow was going and hiding in the bilge. My coolant bundle had perforated. Crap. Salt water in my coolant. I probably flushed that sucker 15 times to get the salt out and $90 in coolant. So I added the recycle bottles so I can see what is going on better.

Silver
Does your engine have a coolant to oil heat exchanger? Some are of the plate design and not easily seen.

 

[Coastie54]

I have a 2005 NP Trawler with twin Cummins 6BT engines. Recent oil analysis (i changed oil in between analysis 1 and 2, and operated 4 hours) came back with high sodium and possible coolant in the oil. There is no milky consistency to the oil, the boat runs well, oil pressure is in range and no exhaust issues. Is it possible this is seawater contamination and not coolant? Is it likely a head gasket or could it be a heat exchanger or oil cooler issue? My engine knowledge is weak and i am hunting for answers before the technician shows up! Thank you!


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What did Jim at Tri-County Diesel say? He seems to be a pretty knowledgeable guy...

 

[Snug Harbor]

Coolant can contain both sodium and potassium as corrosion inhibitors. Seawater has about 40 times more sodium than potassium, so low potassium levels with high sodium levels point to potential saltwater contamination. The sodium and potassium levels rose by roughly equal proportions in your report - this indicates coolant is likely to be the source of the sodium. We've found coolant in oil analysis with no apparent explanation, one common source is a mechanic who uses the same funnel for coolant and oil. Remember that these are trace amounts (PPM) so it doesn't take much. You are doing the right thing - change the oil and re-sample before tearing into the engine.

 

[Vinny]

I had a similar problem before on one of my mains. It ended up being corrosion between a cylinder liners and the block.

Was finding water in oil, looked all over for it with no joy. Finally dropped the oil pan and spotted the weeper from the offending cylinders using a mirror to look above.

Cylinders were all new 4 months before the problem started. Did a DCA test on it using test strips. Chemistry was out of wack causing the corrosion. I’m a true believer of testing the coolant, and replacing the coolant filter regularly now.

 

[rgano]

A cheap double check for a head gasket issue is an exhaust emissions test at the engine's coolant fill.

 

[Rob H]

I have a 2005 NP Trawler with twin Cummins 6BT engines. Recent oil analysis (i changed oil in between analysis 1 and 2, and operated 4 hours) came back with high sodium and possible coolant in the oil. There is no milky consistency to the oil, the boat runs well, oil pressure is in range and no exhaust issues. Is it possible this is seawater contamination and not coolant? Is it likely a head gasket or could it be a heat exchanger or oil cooler issue? My engine knowledge is weak and i am hunting for answers before the technician shows up! Thank you!


View attachment 154504

Silvermb you have gotten a lot of good but sometimes contradictory information here. My suggestion is that you call Chevron and ask their opinion. They have smart people on the help desk that answer these sorts of questions all the time. I'm sure they will understand and be able to explain how after 4 hours your Si is low, K is trending up and Na is high. Water volume is less that a quarter of a percent although that is dissolved water in your sample and may not have captured water that has settled out and sitting in the bottom of your oil pan. I'd call Chevron. I own the same engine although the 250 hp versions that have an after cooler with antifreeze on the liquid side. Good luck...

 

[Greg QS]

Post some pics of the problem engine. Sometimes it is amazing what you can tell from a pic.

Failure in a heat exchanger will cause loss of coolant replaced by sea water but not cause you issue. No connection to the oil.
Oil cooler or turbo failures put oil in coolant due to higher pressure in the oil system over coolant system. Yes coolant can drain into oil when cooled but you would have both conditions. Turbos can crack in the water jacket and leak back into the engine on the exhaust side but you would see other things like a discolored turbo from high heat.
Coolant into oil comes into contact at cooled turbos , head gaskets, heads and block and cylinder liners. The most logical or common failure is head gasket. There are oil and water passages passing through the head and block . Some times the gaskets weep. I don't think there are inspection ports on the Cummins b s . Pull the injectors and us a borescope and look for signs of contamination before going further. Pull the valve cover and look for bead on moisture on the cap. Tell tale sign of moisture where it should not be. . .

I had cummings 6 ctas in my last vessel. I had a head gasket failure. I had a nuance oil leak. The mechanic suspected a failure in the head gasket. He recommended to monitor the leak. We re torqued the head. The oil leak was slow at first , over time it got worse. . Mechanic said when replacing. Yes old style gasket , they get brittle and eventually fail. A known problem. So maybe as simple as that.