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Thermostasis Oil Temperature Control For Rotax 912 Ul / Uls / 914Ul

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Part# 08-07212
MFR Model# P6-H


"Thermostat system designed to regulate the oil temperature of engines with oil coolers installed on the suction side of the oil pump, such as Rotax 912 series engines".

We are all aware of the damage which can be caused by running your aircraft engine oil temperature too low, in fact it has always been recommended to get the oil temperature just over 100C during each flight to burn off the water which can contaminate the engine oil, if you are flying time and time again and the engine temperature is only getting to say 85C the water will remain in your oil as a contaminant and can go on to destroy your engine with corrosion problems. Additionally, warmup is achieved very quickly on even the coldest of days because the thermostat diverts the oil flow from the oil cooler.

Made in the USA these special oil thermostat units are designed to quickly allow your engine to reach and maintain its optimum operating temperature even on the coldest of days.

CNC machined from 6061-T6 the unit is anodised with the type 2 surface finish to protect the thermostat long-term against corrosion.

There are a number of benefits in using an oil thermostat in your aircraft which include fuel savings resulting from quick warmup times and engine operation at optimum oil temperature which also increases engine life because the engine is being operated at the correct oil temperature.

Note: Fittings and mounting hardware are sold separately.
    Stage 1
    Cold oil: the internal oil bypass is open, allowing incoming oil to bypass the oil cooler and returned directly to the engine significantly reducing warmup time.

    Stage 2
    As the oil reaches the desired operating temperature the internal bypass partially closes, automatically regulating and controlling flow through both the internal bypass AND the external oil cooler so that desired operating temperature is maintained.

    Stage 3
    Hot oil: the internal bypass closes completely, directing 98% of the total oil flow through the oil cooler. Under these conditions, the all temperature is limited by the cooling capacity of the external oil cooler.
Will it reduce my oil pressure?
The simple answer is no installing an oil temperature thermostat may slightly increase your oil pressure when it is most needed during cold starts. It offers a shorter, less restrictive flow path to the lubricating oil while the engine is cold. The cold oil bypasses the oil cooler and eliminating the small pressure drop that would otherwise occur.

Can it block the flow of oil?
No, it cannot block the flow of oil in any circumstances whether operating normally or in a failed condition, it is impossible for the unit to block the flow of oil or the oil circuit.

What is the warranty period?
The warranty period of the oil thermostat is two years.

How big is the unit?
The unit is really small being 55mm high, 55mm long (without the hose barbs) and just 40mm deep, the unit can be bolted to the firewall or a bracket with the two 3/16" mounting holes.

Download the ThermoStasis Installation Instructions (PDF)

California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.


Asked for some information before I ordered, got a reply within hours. After ordering, I received the product within a few days on the other side of the world. Very impressed

Alistair J
December 23, 2019

This device works great and as described. After cooling issues with my Rotax 912 ULS in Florida summer time heat I installed the large oil cooler and Thermostais oil thermostat and now oil temperatures are perfect in climb, cruise and low power descents.

Garrett W
July 5, 2019

This really works well. I just installed it on my Ultravia Pelican with a 912ULS. Its a compact unit so finding space was no issue. Installation was straightforward but of course you have to purge the air afterwards. The plane was taking 8 or 9 minutes to come up to 120 degrees, and then running cool at cruise. Today the oil was at 120 in 4 minutes and it maintained around 190 deg for the rest of the flight.

Barry H
January 7, 2019

Excellent addition to my 912ULS. Engine oil gets to temperature in 1/3 the time it used to take and stays at 190 degrees at lower power settings.

Mike S
November 5, 2018


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Is this the P6-H-190 or the P6-H-205?

Our part number 08-07212 is P6-H-190.

Q: How much does this Thermostasis oil temperature control for Rotax 912 UL / ULS weigh?

This unit weighs approximately 0.55 lbs.

Q: What is the temperature at which the oil flow to the cooler is closed off?

Per the supplier: The oil flow is never closed off.

Q: What size are the mounting holes drilled in the body?

The mounting holes are 3/16" diameter.

Q: Will this unit work on a 914UL or is there another part #?

This will work on all 9 series Rotax engines.

Q: Could it be ordered as TSOd part?

No, we do not offer this item as TSO Approved.

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