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Tannas Co. & King Refrigeration, Inc. Precision Laboratory Instruments for Routine Testing and Advanced Research & Development of Engine Oils, Lubricants, and Related Fluids


Thermo-Oxidation Engine Oil Simulation Test

Test Methods

ASTM D6335   |   Dual/33C Model  (Chinese SH/T0750)
ASTM D7097   |   MHT Model (Moderately High Temperature)

Models Available






The TEOST 33C test simulates the effect of engine operating conditions on the oxidation and deposit-forming tendencies of engine oils, especially in the high-temperature Turbocharger area. The TEOST MHT® test simulates similar effects and conditions found in the ring belt and piston ring areas of the engine.

Oil samples treated with catalysts are pumped over a heated 33C Depositor Rod or a coiled MHT Depositor Rod on which deposits form. The weight of the Depositor Rod after the test is subtracted from its pre-test weight and added to the particulate weight collected by filtering the oil remaining. The results are reported in milligrams.

Features & Benefits

  • Adjustable temperature zones and pump speeds.
  • Clear Glass Mantle for easy viewing of depositor area during the test.
  • Ability to collect the volatilized material for further analysis and investigation.

Reference Oils & Catalysts

33C Reference Oils | ASTM D6335 MHT Oils & Catalyst | ASTM D7097 TEOST® Calibration Oil
CG-1 LDF-4 TPC-1
T33C-1 MDF-4

For a complete listing of part numbers and available container sizes of TEOST™ Reference Oils & Catalysts, please review the Tannas Reference Oils & Catalysts Parts List.

Visit our Certified Reference Materials page to download SDS sheets or Oil Certificates.

Parts & Accessories

500700: TEOST™ Dual, 110V, 50/60 Hz Power
500800: TEOST™ Dual, 220V, 50/60 Hz Power
500400: TEOST™ 33C, 110V, 50/60 Hz Power
500500: TEOST™ 33C, 220V, 50/60 Hz Power
500100: TEOST MHT™, 110V, 50/60 Hz Power
500200: TEOST MHT™, 220V, 50/60 Hz Power

Depositor Rods:
500012:  TEOST® 33C Depositor Rods (10 rods/box)
500993:  TEOST MHT® Depositor Rods (10 rods/box)
Optional Accessories:
500990:  33C/Dual Mass Flow Controller
500995:  MHT® Mass Flow Controller
500075:  Thermocouple Depth Gauge
500070:  Two-Channel Chart Recorder - R
500065:  Chart Recorder Paper - R
500024:  Chart Recorder Pen - Black
500067:  Chart Recorder Pen - Red
Spare Parts & Consumables (for either Test):
501000: TEOST Turbo Parts Assembly
500030:  TEOST Filter Cartridges w/Caps
500612:  T/C Main (J-type)
500614:  T/C Over-Temp. (K-type)
500409:  Depositor Rod O-Rings (20/pack)
500892:  Filtering Flask Funnel
500856:  Filter Tube Assembly
500016:  Steel Wool
500019:  Pipe Cleaners (100/box)
500084:  Disposable Pipette
500428:  #8 Rubber Stopper
300995:  Combination Wrench 7/16
500872:  Thermocouple Collar Assembly
020044:  TPC Calibration Oil (0.47 L | pint)
200103:  Syringe (100 microliters)
500076:  Weighing Boats
300815:  Tool Box
500822:  Spare Fuse Set (for either 110V or 220V)
500085:  Plastic Depositor Rod Holder
500715:  Protective Shield
Allen Keys for cabinet (P/Ns 500610, 500611, 500613)
Contact Tannas for additional spare parts, reference oils, and accessories to run the MHT® and 33C tests.


TEOST Rods with description.JPG

Depositor Rods crafted from precision machined steel meet Tannas specifications for exclusive use in TEOST® tests.  All rods undergo a rigorous inspection and measurement process prior to acceptance.


Mass Flow Controllers, utilized for both TEOST® 33C and MHT® tests, introduce various components to the test oil such as reactive gases and air.  The MHT® Mass Flow Controller solely operates with the D7097 test, while the 33C/Dual Mass Flow Controller operates with both ASTM D6335 & D7097 tests.


The TEOST MHT® test utilizes Depositor Rods with a wire-wound center.