Oil temps back to new after all these years

[FlyRatz]

We have a CTSW which offended me all the time with high oil-temp readings. It was one of the machines, which had high temp readings and nobody could tell me why. After a lot of investigations, I found that the temp probes are NTC types. This means, the higher the temperature, the less accurate the reading. At the end, I bought Westach probes from Spruce which are 2-wire and PTC. Dynon supports this probe with type "9" in the setup. (as far as I remember). After this little change, the readings do not rise obove 220°F, even not in glider towing at hot summer days.

 

Maybe it is worth a try for CT

[Ed Cesnalis]

If all you can get at WOT at your altitude is 5500 then flatten the pitch more and unload the work on the engine. This may help bring the temps down a little more.

 

This solution is similar to throttlling back to 5200. It would produce less unwanted heat only because it produces less power. It would mean throttling back to 5500.  In both cases I would be cruising at altitude with a partial throttle and leaving otherwise available power not-accessible.  I want to enhance my cooling not detune my engine because I need every bit of power I can get from a 100hp motor. 

 

Same old story, flying around at 10,000' with a partial throttle is like flying with a partially clogged air cleaner.  There is no benefit.

 

We have been searching for the cause since 2008 and now that we are back to new you changed the goal post.  Notice how you say some need 266 but 240 is where we need to be.  What about the 26 degrees in between?  That's a really big jump and once again the reason is to keep my Dexcool from boiling but the Dexcool doesn't get hot.  That's a BS reason.

 

I'm happy hitting 250 for a few minutes instead of 265 for 15 minutes.  If the former is so bad how is it the latter has worked and been ok for 8 years? 

[FlyingMonkey]

Roger, I'd like to see a pic of your trimmed radiator opening so I get an idea of what it should look like when done.  If I could get it cooled by 10°F I'd be a happy camper.

[Tom Baker]

Hi Tom,

 

Those are UL temps and not ULS. Remember the manuals are written for 3 basic engines. ULS max CHT head temp is 275 and coolant is 248. Max oil is 266, but with 50/50 it should be held to 248.

 

OK, I concede, I pulled the numbers for the wrong engine. That being said, the Rotax number is still 266F for max oil temp, not 248F.  For the coolant to boil it is the coolant temperature that you have worry about, not the oil temp. Having a high oil temp shouldn't be an issue that would cause the coolant to boil, unless the coolant temp was also high.

[Roger Lee]

If his temps go that high he has a problem or he has a setup issue with the engine or prop. None of the rest of us go that high. Even 250 here has been rare.

Going to max temps on a regular basis is just asking for an expensive issue.

[Tom Baker]

If his temps go that high he has a problem or he has a setup issue with the engine or prop. None of the rest of us go that high. Even 250 here has been rare.

Going to max temps on a regular basis is just asking for an expensive issue.

 

I don't disagree with any of that. What I am saying is having a high oil temp like that has nothing to do with boiling the coolant. To boil the coolant you have to have a high coolant temperature independent of the oil temp.

[Ed Cesnalis]

If his temps go that high he has a problem or he has a setup issue with the engine or prop. None of the rest of us go that high. Even 250 here has been rare.

Going to max temps on a regular basis is just asking for an expensive issue.

 

The new condition that I have produced 250 for a few minutes when in the past it would have produced 265 and interrupted my climb.

 

After 8 years I realize this big improvement but its too hot, yet it happens there and you guys are the standard.

 

I say 250* oil in CA is the same as 250* oil in AZ.  

[Roger Lee]

I was just stating the max temps and usually when one temp is off the charts others follow and there is no reason to settle for those high temps. There has to be something going on since the other 370 or so CT's aren't seeing those temps. He is one of the very few that flies at 5500 WOT all the time.

[Ed Cesnalis]

I was just stating the max temps and usually when one temp is off the charts others follow and there is no reason to settle for those high temps. There has to be something going on since the other 370 or so CT's aren't seeing those temps. He is one of the very few that flies at 5500 WOT all the time.

 

My new max is 250*, hard to see how that is off the charts when others have same or worse and its 16* shy of redline.  Also now cruising at 220* instead of 230*.  I'm no longer a hot running outlier. 

[Roger Lee]

Those temps aren't terrible. The climb of 250 is a tad high, but not terrible and livable. 220 in cruise at your rpm would be very normal.

 

Now ask yourself what changed that hadn't changed before?

 

Inquiring minds want to know.

[Ed Cesnalis]

Those temps aren't terrible. The climb of 250 is a tad high, but not terrible and livable. 220 in cruise at your rpm would be very normal.

 

Now ask yourself what changed that hadn't changed before?

 

Inquiring minds want to know.

 

The rubber seals at the coolers.  They were deteriorating and Jeremy replaced them and the temps came down immediately.  Oil and coolant both came down.  We never suspected the rubber before because it looked good until recently.

[Roger Lee]

The rubber seals must be firm enough and up against the cowl walls for them to work properly and channel the air. If not air just blows around and not as well through them. You may also benefit from opening the cowl up a tad in front of the radiator.

[SportFlyer1]

I took off from KGYR Monday and at 500 feet I got a high CHT alarm. I reduced throttle some continuing to pattern altitude and requested a return. The engine alarmed all through the downwind and finally cooled enough on short final for the alarm to shut off. That was a first for me with this plane, the outside temp was an even 100.

 

After inspecting hoses, coolant and oil levels all looked good and there are no leaks. On ground runup the CHT is still alarming at 250, with one of the CHT's persistently higher than the other. I'm baffled, unless you just can't run this engine at over 100 degrees.

[Ed Cesnalis]

I think there is an ambient temp, for me its around 100 degrees where you have to shut down if your  in line for take off and the take off and initial climb are all at oil redline but as you get some altitude temps begin to normalize.  I'm sure if you have Dynon warnings they would be going off before you got off the ground.

 

When the line gets fine consider what kind of oil you are running.  If your CHT's are at boiling I wouldn't do it.

[Tom Baker]

I took off from KGYR Monday and at 500 feet I got a high CHT alarm. I reduced throttle some continuing to pattern altitude and requested a return. The engine alarmed all through the downwind and finally cooled enough on short final for the alarm to shut off. That was a first for me with this plane, the outside temp was an even 100.

 

After inspecting hoses, coolant and oil levels all looked good and there are no leaks. On ground runup the CHT is still alarming at 250, with one of the CHT's persistently higher than the other. I'm baffled, unless you just can't run this engine at over 100 degrees.

 

The coolant thermostat is likely stuck closed. I had a customer airplane do this a couple years ago. You can check by feeling the radiator, if it does not feel like 250° then coolant isn't flowing through it. With the top cowling off you can reach down and tap the thermostat with a wrench, and it might pop open. Check with Flight Design USA. I think they have a NAPA number that will work as a replacement.

[Anticept]

The termostats, if it's the rotax one (upper right corner as pictured), are serviceable. Mine just had a leaky o-ring. They are pretty inexpensive already, but it's stupidly easy to replace the vernatherm inside of them if you don't want to deal with the mess of disconnecting everything. Here's the company that makes them, just call and ask: http://shop.perma-cool.com/Oil-Thermostats_c10.htm

[Tom Baker]

The termostats, if it's the rotax one (upper right corner as pictured), are serviceable. Mine just had a leaky o-ring. They are pretty inexpensive already, but it's stupidly easy to replace the vernatherm inside of them if you don't want to deal with the mess of disconnecting everything. Here's the company that makes them, just call and ask: http://shop.perma-cool.com/Oil-Thermostats_c10.htm

Sport flyer 1 was talking about high CHT. That would be the coolant thermostat not oil.

[Anticept]

Hey i just got back a few hrs ago from an aircraft recovery on the other side of the state in the hot and humid ohio weather. Give me a break

[Tom Baker]

Hey i just got back a few hrs ago from an aircraft recovery on the other side of the state in the hot and humid ohio weather. Give me a break

 

I did the recovery thing earlier in the week. A pair of tires and tubes, then dodging thunderstorms on the flight home. On the bright side it was just an hour drive, and not all the way across the state.

[Anticept]

This was a trailered recovery. Sprag broke. Then we too got hit by a thunderstorm on the way back. Winds picked up to 40 mph, 70 in a few places. We huddled right up next to a home depot and it made a lot of conversation while we stayed inside.

[207WF]

So, Ed,

 

I infer that having your oil radiator pressure cleaned had no significant effect? 

 

I am on the verge of going ELSA, just so I can install the new larger rotax oil cooler.  Has anyone done that?  Do you know if it will fit in a CT without changing the cowling? 

 

On a trip to Utah last week I saw 40C (104F) air temp in the climb out of the LA basin due to an inversion, and my "new" technique of keeping the power full in and using the RPM gauge as primary for pitch (holding 5300 rpm in the climb) was inadequate.  I had to fall back on my previous technique of powering back, trowing out flaps 0, and slowing.  It took me a full hour to get to 9500 feet, and even then the oil temp was briefly as high as 252 (I use 250 as my max before I have to do something).  I also saw oil temps as high as 245 during cruise on this trip.  WF

[gbigs]

So, Ed,

 

I infer that having your oil radiator pressure cleaned had no significant effect? 

 

I am on the verge of going ELSA, just so I can install the new larger rotax oil cooler.  Has anyone done that?  Do you know if it will fit in a CT without changing the cowling? 

 

On a trip to Utah last week I saw 40C (104F) air temp in the climb out of the LA basin due to an inversion, and my "new" technique of keeping the power full in and using the RPM gauge as primary for pitch (holding 5300 rpm in the climb) was inadequate.  I had to fall back on my previous technique of powering back, trowing out flaps 0, and slowing.  It took me a full hour to get to 9500 feet, and even then the oil temp was briefly as high as 252 (I use 250 as my max before I have to do something).  I also saw oil temps as high as 245 during cruise on this trip.  WF

 

Try climbing at full power, flaps -6 and pitch  for 60kts.

[Ed Cesnalis]

So, Ed,

 

I infer that having your oil radiator pressure cleaned had no significant effect? 

 

I am on the verge of going ELSA, just so I can install the new larger rotax oil cooler.  Has anyone done that?  Do you know if it will fit in a CT without changing the cowling? 

 

On a trip to Utah last week I saw 40C (104F) air temp in the climb out of the LA basin due to an inversion, and my "new" technique of keeping the power full in and using the RPM gauge as primary for pitch (holding 5300 rpm in the climb) was inadequate.  I had to fall back on my previous technique of powering back, trowing out flaps 0, and slowing.  It took me a full hour to get to 9500 feet, and even then the oil temp was briefly as high as 252 (I use 250 as my max before I have to do something).  I also saw oil temps as high as 245 during cruise on this trip.  WF

 

Wayne,

 

The hot flush was effective, and the rubber seals more so.

 

I'm going to go experimental and change the coolers, its pretty cheap that way.

 

Here's a picture of the upgraded oil cooler.  If I remember correctly its the same size it just has more  rows.  FD coolers are welded together but these look easy to bolt together, forget where I saw brackets for that.

 

We should probably have Jeremy do both of ours, lets face it more capacity is needed even if others say we are crazy.

 

 

 

Edit:  I see Lockwood on that image so it might not be the right one.  I found the right one by talking to the manufacturer. 

[Brucegoose]

I went experimental and separated my oil cooler from the radiator and configured to the same as the Sling LSA built here in SA.

In all weather conditions my temps are rock solid 185 to 203 deg F. I had to install coolant and oil thermostats as I had over cooling in winter

with OAT of 40 deg F. Summer OAT's in the 100 deg plus not a problem. No rubbers to channel more air flow as the intake is a pocket and air is forced through the radiator.

Happy flying to all.

Regards

Bruce

[Ed Cesnalis]

I went experimental and separated my oil cooler from the radiator and configured to the same as the Sling LSA built here in SA.

In all weather conditions my temps are rock solid 185 to 203 deg F. I had to install coolant and oil thermostats as I had over cooling in winter

with OAT of 40 deg F. Summer OAT's in the 100 deg plus not a problem. No rubbers to channel more air flow as the intake is a pocket and air is forced through the radiator.

Happy flying to all.

Regards

Bruce

 

 

Any photos?