Oil cooler sanity check

[riseric]

This is in “Temporary” as it concerns a friend’s airplane (not RV).
I’m reaching out to the collective mind in hope of opinion, especially if one here has or had a 1975 or similar Piper Warrior.
Mods, remove this thread if inappropriate.

For a while now, the pilot (not new to this plane) complains of high oil temps. 235F in climb, 220F in cruise.
STD O-320

Talked to me about it, first thing I asked, “Is the winter kit removed?”
He says that it is.
He mentioned this high temp to his mechanic and he changed the Vernatherm “for diagnostic purposes”.
No improvement in temps.
I suggested to check the temp sensor in hot water. Not done yet.
The owner is also suspecting the cooler.
I went for a short flight with him and I confirm the high temps. In cruise, reducing the RPM by 100 produced a 10F drop.
8C at 4500 ft
(boy this is slow compared to the 8 !!)

POH says oil temps are “green” all the way to the red line at 245F. Typical Lycoming data.
After landing, I popped the cowl open and saw this !!
Owner is convinced that this is not part of the winter kit.
The mechanic might not have seen this, or maybe he has, I don’t know.

I never owned a Warrior, although I flew one decades ago and never worried about high oil temps.
If this were mine and I was concerned about high oil temps, I’d remove or have remove this plate for “diagnostic purposes”.

Ready to receive opinions, especially if you know about Warriors.
Thanks
(edited to add info)

 

[lr172]

regardless of what you call that cover, it is going to seriously reduce airflow through the cooler (massive turbulence at exit) and thus seriously reduce its cooling capacity. know nothing about warriors, but do believe i understand restrictions to airflow, albeit not an expert. can definately see why one would put that on for winter ops.

 

[Sam Buchanan]

Due to all the paint scratches it was probably removed seasonally.

 

[rmarshall234]

High oil temps??….he should take that stupid plate off the back of the cooler and go fly and see what changes. Larry is right about it reducing cooling capacity.

 

[Hotstart]

We had a 1975 Warrior for over a quarter of a century.

I’ve attached the page of the Service Manual that shows the baffle on the back of the oil cooler as part of the airplane’s design equipment.

We never had issues with high oil temperatures, but did have issues with low oil temperatures in the winter. There is a blanking plate that fits over the front of the cooler which we installed for winter ops.

There’s likely another reason for the high oil temperature.

The Lycoming SSP-475 Troubleshooting Guide provides a list of possibilities on page 19.

 

[PhatRV]

I flew a rental Warrior for 120 hours while building my RV8. I think it's difficult to compare the Warrior to the RV8 because the Warrior's cowl is so leaky. Of all the RVs in the very warm SoCal that I had a chance to look at, none of them has the blocker and none of them has any hot oil issue.