Hello everybody:

I am a newcomer of this forum.

We are operators of large Diesel engines that burns Bunker C fuel oil. The lube oil used is a Texaco TARO 50XL40, it is TBN 50.

The people in charge of operations periodically performs a "refreshing of the oil", this is, they add a certain quantity of brand new oil to the carter. All this in order to alleviate the oil degradation (TBN reduction).

We have not a real knowledge of this practice and maybe we are taking no good decisions.

Can someone in this forum give me advice on this subject? I would like to know what is a good and technically accepted practice for the refreshment. What parameters must be taked into account for refresh or change the lube oil?

Thanks

Hello and welcome.

You should monitor the precense of fuel/MDO to detect evt. blow by during combustion and overusage of fuel. Also monitor water content, soot content and wear elements together with oil properties.

I belive it is common to top up with compatibile oils when the alkaline properties are reduced (TBN and Ca). It should always be done together with oil analysis.

If you need specialists on this subject I would recommend: Flame Marine
(Note: I do not work for Flame Marine)

Hi mr. Hughes:

Thanks for your valuable post.

Certainly, once a week oil samples are taken from the engines and sended abroad, so the results are returning back withing aprox. 15-20 days. During that time, controls of TBN on site are performed and with the results (or without them), a lot of refreshments are made.

The time between refreshments is 50 operating hours; this because in the opinion of the manufacturer, it is easier (and economical for us) to maintain the TBN value near to 50 in this way than to wait untill, i.e. 12000 operating hours to achieve a total drain and refill with new oil.

Thanks