Thermo-oxidation Engine Oil Simulation Test

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.

Models Available

TEOST Turbo®

ASTM D6335 | Dual/33C Model (Chinese SH/T0750)
ASTM D7097 | MHT Model (Moderately High Temperature)
ASTM D8447   |   TEOST Turbo®


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

Dimensions: (W x D x H) Bench-top: 33 x 50 x 56 cm, 13 x 19.5 x 22 inches
Weight: 30 kg | (64 lbs.)
Voltage: 120 or 220 VAC , Single Phase, Power Draw – 5 amp.
Frequency: 50/60 Hz.
Depositor Rods: 33C: Precision steel, MHT™: Precision steel with specially treated wire winding
Sample Volume: 33C: Total – 250 mL — Actual Volume Tested – 116 mL (100 mL plus 16 mL left in lines after flushing), MHT™: 8.5 grams (± 0.001 g)
Operating Temperatures: 33C: Reactor Temperature: 100°C (±1°C), Depositor Temperature Cycle: 200°C to 480°C at designated time intervals, MHT™: Constant 285°C
33C Test Parameters: 12 Heating Cycles: 9.5 minutes/cycle, 114 minute total test time, Pump Rate: 0.45 mL/min. or 0.40 g/min., Moist Air Flow Rate: 3.6 mL/min. through H2O
N2O Flow Rate: 3.6 mL/min. through H2O, Iron Naphthenate: 100 ppm
MHT™ Test Parameters: Test Time: 24 hours, Pump Rate: 0.25 g/min., Dry Air Flow Rate: 10mL/min., MHT Catalyst: Refer to bottle
Safety: CE Mark, Current Limiting Fuses & Over-temperature Cut-out Fuse, Protective Heat Shield
Shipping Weight: MHT™ or 33C: ~60 kg | (132 lbs.), Dual: ~82 kg | (180 lbs.)
Shipping Dimensions: (W x D x H) MHT™ or 33C: 1 Pallet | 61 x 81 x 89 cm, Dual: 2 Pallets | 84 x 61 x 84 cm | 79 x 61 x 71 cm

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):
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 the cabinet (P/Ns 500610, 500611, 500613)

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.