Replacement of lubricating oil
The expected lubricating oil lifetime in operation is
difficult to determine. The lubricating oil lifetime is
depending on the fuel oil quality, the lubricating oil
quality, the lubricating oil consumption, the lubricat-
ing oil cleaning equipment efficiency and the engine
operational conditions.
In order to evaluate the lubricating oil condition a
sample should be drawn on regular basis at least
once every three month or depending on the latest
analysis result. The lubricating oil sample must be
drawn before the filter at engine in operation. The
sample bottle must be clean and dry, supplied with
sufficient indentification and should be closed
immediately after filling. The lubricating oil sample
must be examined in an approved laboratory or in
the lubricating oil suppliers own laboratory.
A lubricating oil replacement or an extensive lubri-
cating oil cleaning is required when the MAN Diesel
& Turbo exchange criteria's have been reached.
Evaluation of the lubricating oil condition
Based on the analysis results, the following guid-
ance are normally sufficient for evaluating the lubri-
cating oil condition. The parameters themselves can
not be jugded alonestanding, but must be evalu-
ated together in order to conclude the lubricating oil
condition.
1. Viscosity
Limit value:
Normal
value
min.
value
max.
value
SAE 30 [cSt@40° C]
SAE 30 [cSt@100° C]
SAE 40 [cSt@40° C]
SAE 40 [cSt@100° C]
95 - 125
11 - 13
135 - 165
13.5 - 15.0
75
9
100
11
160
15
220
19
Unit : cSt (mm
2
/s)
Possible test
method
: ASTM D-445, DIN51562/53018, ISO
3104
Increasing viscosity indicates problems with insolu-
bles, HFO contamination, water contamination, oxi-
dation, nitration and low load operation. Decreasing
viscosity is generally due to dilution with lighter vis-
cosity oil.
2. Flash point
Min. value : 185° C
Possible test
method
: ASTM D-92, ISO 2719
Normally used to indicate fuel dilution.
3. Water content
Max. value : 0.2 %
Unit : Weight %
Possible test
method
: ASTM D4928, ISO 3733
Water can originate from contaminated fuel oil, an
engine cooling water leak or formed as part of the
combustion process. If water is detected also
Sodium, Glycol or Boron content should be
checked in order to confirm engine coolant leaks.
4. Base number
Min. value : The BN value should not be lower
than 50% of fresh lubricating oil value,
but minimum BN level never to be
lower than 10-12 at operating on
HFO!
Unit : mg KOH/g
Possible test
method
: ASTM D-2896, ISO 3771
The neutralization capacity must secure that the
acidic combustion products, mainly sulphur origi-
nate from the fuel oil, are neutralized at the lube oil
consumption level for the specific engine type.
Gradually the BN will be reduced, but should reach
an equilibrium.
5. Total acid number (TAN)
Max. value : 3.0 acc. to fresh oil value
Unit : mg KOH/g
Possible test
method
: ASTM D-664
TAN is used to monitor oil degradation and is a
measure of the total acids present in the lubricating
oil derived from oil oxidation (weak acids) and acidic
products of fuel combustion (strong acids).
MAN Diesel & Turbo
1609533-1.7
Page 1 (2)
Criteria for cleaning/exchange of lubricating oil
B 12 15 0
L23/30S, L28/32S, L27/38S, L21/31S, L16/24S, L23/30DF, V28/32S-DF, L28/32DF,
V28/32H, V28/32S, L16/24, L21/31, L23/30H, L27/38, L28/32H
2015.11.27
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