Underhood Temperature Near Oil Filter

Underhood Temps Near Oil Filter

Background:

As one theory goes the opening on the passenger side of the intake duct is there to assist with generating airflow in the area of the oil filter.

Mk7 GTI Inlet Duct Test
Mk7 GTI Inlet Duct Test

The Test:

To test this idea the GTI was equipped with a temperature sensor that is placed near the oil filter, directly behind the opening in the intake duct.

Temperature Probe - Open Duct Test
Temperature Probe – Open Duct Test

The GTI is driven on a route that is conducive to maintaining steady speeds.

Intercooler Test Route
Intercooler Test Route

The temperature at the underhood location is recorded under two conditions, the first with the stock intake duct closed, and the second with an Eventuri intake installed that allows the passenger side to be open.

The Results:

Temperature readings from the two drives are shown on the chart below.  Ambient air temperature was the same during each drive.

Underhood Temperature Near Oil Filter
Underhood Temperature Near Oil Filter

From approximately time 900 onward the air temperature is slightly cooler with the passenger side of the intake open.

Oil temperature during the drives was also recorded and is shown on the next chart:

Oil Temperature During Loop Drive
Oil Temperature During Loop Drive

There is no indication that oil temperature is affected by the state of the intake opening.

Conclusion:

Underhood temperature near the oil filter is slightly lower when the passenger side intake is open to allow airflow into the engine compartment.  Oil temperature does not show signs of being affected by the state of the opening.

8 thoughts on “Underhood Temps Near Oil Filter”

    1. The car has had one of those for a while. I doubt it does anything other than add a shiny part under the hood.

  1. Nice work – this one always gets brought up as to the reason for that opening.

  2. Aaron Chamberlain

    Not surprising, the “oil cooler” is an oil/water heat exchanger. In this scenario of just normal driving around, coolant temp is probably going to have the biggest impact on the minor deviations in oil temp–that should have been used in the graph as well IMO. Either way, I’m glad we can put this one to rest, lol.

  3. only way ti decrease oil temp is by oil cooler or bigger oil pan made of steel or aluminium.

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