Sodium in Engine Oil

Bought a used 2011 Durastar 4300 with the Maxxforce DT in March of 2014.

150,000 KM's (93,000 miles) and 4100 hours on it now.

Last couple oil changes I have sent in a sample and they have both come back high sodium levels.

Oil tests negative for glycol and finning is saying sodium is produced by combustion of antifreeze.

Have been buying my coolant from the International dealer and they tell me the coolant has no silicates in it.

EGR valve has been replaced as well as ICP valve but samples keep coming back with high sodium levels.

I have to replace anywhere from 200ml to 1L (8 to 33 .oz) of coolant per 10 hour day since my first day operating the truck. All though some days I don't have to replace any.

Can someone please tell me where the high sodium levels may be coming from or where my coolant may be going?

Thanks for any help you can give.

 

Thanks for the replies everyone.

I am buying the sample kit from my local international shop but the results come back from Finning labs.

I am using Shell Rotella 15W40, not synthetic just plain old oil.

I have done 3 oil changes since buying the truck in March of this year. Last two changes I sent in used sample. I was thinking of sending virgin sample as well just to rule out high sodium levels as Cowpie suggested.

I will make sure drainplug is very clean next time I sample but I have a hard time believing that can be the source, but I am definitely going to see if it makes a difference.

Cranky: would a head gasket or oil cooler leak show glycol in engine oil sample? Test results are coming back negative for glycol in oil.


HeavyD: I asked the mechanic at the shop if it could be my EGR cooler and he says he has never seen one leak a little bit, they usually dump all the coolant right through it. Also, apparently EGR cooler was just replaced before I bought the truck. Not sure how I should proceed from here on that point.


I am also getting the check engine light on, not sure if that has anything to do with replacing coolant every day.

Thanks for the help everyone.

 

OK, so if it was a head gasket, cracked cylinder head, or oil cooler leak I would see glycol in oil sample? Or maybe oil in coolant tank?
Not a mechanic so just want to make sure I understand

When I first got the truck I took it into the shop and told them I was losing coolant somewhere and they told me the EGR cooler was fine and in fact it had just been replaced. They did say they tested my rad cap and it was leaking so I bought the International $40 rad cap but still had to replace coolant every day since. This was in March of this year. I have been adding every day since.

Is there a way that I can check or test the EGR cooler myself or can you recommend somewhere I can purchase a manual outlining the procedures?
Then at least I could feel confident going back to the mechanic and saying yes I really feel its my cooler leaking and maybe I might still be able to get it under warranty. They haven't seemed too keen on changing it up to this point.

I think I read somewhere on this forum about looking inside it for coolant but I have no idea where I would start taking it apart.