COMPOSITION AND OXIDATION STABILITYOF
SAE 5W-40 ENGINE OILS
Department of Petroleum Technology and Petrochemistry, Institute of Chemical Technology
Technicka 5, 16628 Prague, CZECH REPUBLIC; e-mail:
[email protected]
Composition of base oils was studied by gas and liquid chromatography techniques after separation of additives from
SAE 5W-40 engine oils. Ratio between hydrocracked oil and synthetic PAO was assessed from the GC chromatograms
for semisynthetic engine oils or the fully synthetic basis of engine oils was confirmed. FTIR spectroscopic analysis of
engine oils revealed a presence of esters as a part of base oils in some of the engine oils and approximate concentration
of the esters was determined. Oxidation stability of the SAE 5W-40 engine oils was examined by using a modified high
temperature oxidation test IP 48. Evaluation of oxidation tests was done by determination of some standard engine oil
parameters, such as viscosity, carbon residue, and acid number. FTIR spectroscopy was used for determination of
concentration increase of carbonyl bonds after oxidation tests. Fully synthetic engine oils mostly showed a better
oxidation stability than semisynthetic oils. However, some fully synthetic engine oils exhibited decreased oxidation
stability even in comparison with semisynthetic oils most likely due to an inappropriate choice of additive package
All 5w-40 Synthetic Oils. API, SJ. ACEA, A3, B3
Composition, 1st No PAO ( %rel), 2nd No HC (%rel) 3rd No Ester (wt%)
BP Visco 5000
40, 60, 0
Castrol TXT Softec Plus
25, 75, 0
Elf Synthese
100, 0, 0
ESSO Ultron
100, 0, 10.0
Mobil 1
100, 0, 0.23
Shell Hellix Ultra
0, 100, 8.5
Total Quartz 9000
100, 0, 8.5
Texaco Havoline Formula 3
100, 0 , 0
Pennzoil Performax
100, 0, 0
Mogul Forte Racing
100, 0, 4.0
Mogul Forte Racing New
75, 25, 0
Old rating but to me gives some idea of the mix of base oils.
