Hi gang.
I have the Stewart Warner oil cooler on the baffle behind cyl # 4 (IO-360) per Vans plans.
In front of the cooler, I have installed the oil cooler shutter from Vans.
Up until now, (210 hrs) it's been working ok, but Fall has come to Norway now, and the OAT's are dropping.
During the last few flights, I have noticed that I'm not able to keep the oil-temp to where it has been up until now; 180-200*F during cruise.
Temps are in the 150-160*F range with OAT's around 35-40*F and a powersetting at 55% (21/2100).
So far, it looks like the oil temp is dropping along with the OAT as they are getting lower.
For example: I can take off on the first flight of the day with the shutter fully closed and a oil-temp around 100*F and increasing.
Then, at for example 5000', the oiltemp is 180-190 and when reducing to cruise-setting, the oil-temp start dropping to the 150-160 range.
This is NOT the way the oil temp has been during low OAT's before, because the shutter has always been able to keep the oil-temps up, even on low powersettings.
Therefore I'm wondering if anything has happened with the oil-cooler.
It has some kind of thermostat inside, right? Vernaterm valve or something?
I think I've read somewhere that this valve in the cooler never goes to fully closed; there's always some oil flowing past the valve, even in low OAT's.
But seeing that I'm not able to keep up then temps like before, I'm wondering if that valve has failed to full open? Or is such a failure not possible?
I don't have a clue of the inside of a cooler, but hopefully there's someone out there who knows more than me about this.
What I do know however, is that something prevents the oil-temps to be in normal range. I've not had any problems keeping the oil temp up during the last three winters I've had the RV.
Any good ideas where to start looking?
I have the Stewart Warner oil cooler on the baffle behind cyl # 4 (IO-360) per Vans plans.
In front of the cooler, I have installed the oil cooler shutter from Vans.
Up until now, (210 hrs) it's been working ok, but Fall has come to Norway now, and the OAT's are dropping.
During the last few flights, I have noticed that I'm not able to keep the oil-temp to where it has been up until now; 180-200*F during cruise.
Temps are in the 150-160*F range with OAT's around 35-40*F and a powersetting at 55% (21/2100).
So far, it looks like the oil temp is dropping along with the OAT as they are getting lower.
For example: I can take off on the first flight of the day with the shutter fully closed and a oil-temp around 100*F and increasing.
Then, at for example 5000', the oiltemp is 180-190 and when reducing to cruise-setting, the oil-temp start dropping to the 150-160 range.
This is NOT the way the oil temp has been during low OAT's before, because the shutter has always been able to keep the oil-temps up, even on low powersettings.
Therefore I'm wondering if anything has happened with the oil-cooler.
It has some kind of thermostat inside, right? Vernaterm valve or something?
I think I've read somewhere that this valve in the cooler never goes to fully closed; there's always some oil flowing past the valve, even in low OAT's.
But seeing that I'm not able to keep up then temps like before, I'm wondering if that valve has failed to full open? Or is such a failure not possible?
I don't have a clue of the inside of a cooler, but hopefully there's someone out there who knows more than me about this.
What I do know however, is that something prevents the oil-temps to be in normal range. I've not had any problems keeping the oil temp up during the last three winters I've had the RV.
Any good ideas where to start looking?