[foxmoth]

We are getting high oil temps on our Ma5 Charger - IO360 engine, still within limits but worryingly close, anyone any clues?
Compressions are all good and nothing obvious that we can find.

[riverrock]

https://www.google.com/amp/s/www.thesun ... atwave/amp ?

Does your oil cooler have a thermostatic bypass valve (so when oil is cold it skips the cooler)?
Check if guage is reading correctly.
You should also notice temperature drop on exit of oil cooler, but hard to measure.

[Rob L]

Check the oil filters for flow restriction? That was my symptom also :



(it's an old story now, but can be found here )

[Charliesixtysix]

Are temps high all the time, or when just when the oil is older?

I change every 25hrs and notice lower oil temps with new 15w-50 oil in high ambient temps such as recently experienced in UK and France this summer.

E.g Sunday, indicated 99C in climb and 91-92C at cruise before change - Monday, 92C climb dropping to 86-88C with new oil at same oil qty, cruise power, speed and near enough the same oat.

[foxmoth]

Are temps high all the time, or when just when the oil is older?

We wondered if that might be the case, just done an oil change (and changed/cleaned the filters) but no change

[Charliesixtysix]

Are the symptoms worsening with time or has it always run hot?

What pressures do you see - range tick over to full power, and have they been constant with time?

[foxmoth]

It used to be ok, all else seems normal

[T67M]

I think this thread on high oil pressure, normal temperature gives all the reasons you could ever need as to why any abnormality should be investigated by an experienced engineer.

[Charliesixtysix]

Something must be changing (or have changed) to cause the increase in temperature. It looks like you have taken account of recent high ambient temperatures and have checked the obvious things already, so now is probably the time to do a bit more diagnostic work on the engine and oil cooler system before it gets any worse.

[PeteSpencer]

Just noticed this: We had a similar problem with our IO360 in our Arrow last summer:
Turned out the stem of the Vernatherm valve had become distorted: Replacing the Vernatherm cured the problem instantly/

Peter

[Charliesixtysix]

Any progress with solving the Charger’s problem?