Engine oil running 230 today

[Scrapman1959]

Flying home from work this afternoon my engine oil hit 230 and I had to pull throttle back to 5000 to keep it at 220. DA was 5000 ft, Cruising at 2400ft and OAT was 86 farenheit. Ten gallons total on board and my 160 lbs, so was very light. This was our first warm day this year, so problem may have been there some of the winter and not knowing it. It's a 2011 CTLS just over 500 hours. Everything else was normal temps. CHT's around 235 I think, but can't be sure of that, they were in the green. Any suggestions on what to try after I run hot water through the radiator and oil cooler to clear them of possible dirt and bugs which are not present looking at the front of the radiator. I do land on a grass strip daily and then taxi across a gravel road to hanger it, and this does make for some dust. Of course the winter shutters for the radiator were taken off a few weeks ago, so no tape etc blocking radiator.

[Roger Lee]

The best answer I can give you is 230F is nothing and don't worry about it. Are you using 50-50 coolant? On out CT's prop pitch many times is the problem. You will be better served to make the prop pitch to achieve 5600-5650 rpm at WOT flat and level. This will help with cooling by unloading your engine work load. This will also give you the best balance for flight characteristics. I fly much heavier and with higher OAT's and I'm usually around 220F. Make sure the radiator is up as close as possible to the cowl opening. Make sure the radiator rubber skirt is in the proper position. Make sure no oil or coolant hose have reduced radius's in them.

[Scrapman1959]

I have the prop set at 5550 WOT and had to pull power back from 5250 to 5000 or under to keep the oil temp out of the yellow. If I ran at 5250 it just kept climbing into the yellow. Something is wrong. Nothing has changed on this bird since it was new. Baffling and all is in right place. Hoping it's just a little dirt in the oil cooler.

[Ed Cesnalis]

Some of us have CTs that began 'running in the yellow' and we never figured it out. I have to climb above the altitude where OAT is 70F to get in the greeen.

 

Been that way for years now.

[Roger Lee]

If all you see is 230-235 I wouldn't sweat it. It's only in the yellow. That means just keep an eye on it. This isn't overly hot.

 

Do you have to older paper element air filter? Going to a K&N can help. Re-routing the hose off the bottom of the engine to the oil tank and making it straight out to the left for easier flow may help if it has a reduced radius.

 

There may be absolutely nothing wrong and the VDO oil temp probe could easily be off 5F+. Unless the oil temp was actually tested against the probe temp and nothing has changed this may be my first guess.

[mocfly]

Scrapman,

Along with getting the grounding problems corrected, using various means including the manufacture of a probe body grounding device, we sent the probe and the guage to UMA and had them matched. Cost was minimal. This was for both the cht and the oil. We also made sure both coolers has straight fins, centered in the lower opening, cleaned with a low pressure power washer. We have yet to see the problems that have plagued us since we purchased the aircraft.

 

I say that with caution as summer begins and the temperature begins to rise. We will see.

 

Be mindful of what Roger says about instrument accuracy. I would check the instrument manufacturers information included with your aircraft for the tolerance.

 

One last thing we did was to separate the oil cooler from the water radiator and re-installed it with the hardware required. I believe the early models had the oil cooler welded to the water radiator. If you download the parts manual you will see the different iterations of oil cooler/water radiator mounting. Seems like it couldn't hurt.

 

[CT4ME]

This time of year here in Phoenix, every climb-out can see yellow easily. I just try to keep it in lower side of Yellow... by being less aggressive on the climb... 'kinda fixes itself after gaining several thousand feet.

tim

[Roger Lee]

Is the oil temp bouncing around a little about 4-15F? If so download the Dynon oil temp program fix from our forum I have posted. Then take a look at the temps.

[Scrapman1959]

Temp was rock solid not moving, just up and down with power settings on the trip home last nite. Flew to work this morning in cool air and everything was fine, 208 at 5250 rpm. Washed out the radiator and hopefully the oil cooler with a garden hose only, at work. Flight home OAT was 70 and I ran it 5350 for 15 minutes and it got the oil to 218 rock solid reading. Then went from 5350 to 5550 (WOT) for 4 minutes and it wouldn't pass 220 degrees. Sure seems to be running much cooler, although it was 16 degrees cooler OAT. The fact that the power settings are making very little change now in the temp tells me the oil cooler is working good, I hope.

[Tip]

I flew to Ohio State University on Tuesday. A four hour round trip and still had 6 inches of tape on my radiator. Never read out of the green. I flew in snow on Monday! What's up with your weather up North?

[Doug G.]

We like to surprise people.

[opticsguy]

Seriously, I used tape in 75F weather last weekend (about 2 inches) just to keep my oil above 190F. There seems to be a huge variation in how well these engines cool themselves.

[Roger Lee]

The factors betweeneachplane is influenced by prop pitch, radiator alignment, carb balance, hose radius influenced by bends and routing, cruise rpm , climb rpm, rate of climb, ect...

[mocfly]

It is surprising that radiator alignment, radiator angle, hose length, hose radius and hose routing hasn't been standardized using best practices. It is pretty easy to put together a spreadsheet to collect the data required to come up with the required output. Using one of the ANOVA Six Sigma tools would enable us to analyze the relationship between several inputs and the one output(oil temp). This would enable those who struggle with high oil temps with no visible abnormality, to zero in on one or two items which affect the temperature the most. (I KNOW PROP PITCH)

Unfortunately, my feeling is that the members of this group may not or would not be willing to be part of this type data mining exercise. It does take some time and adjustments to collect and record the data points. So we continue to make individual adjustments with the hope of finding the one adjustment that provides the means to lower the temp. I am also part of that group.

With the above being said, if a majority of the members of this forum agree to gather the data I would be happy to generate the paperwork required to gather the data and then publish the results.

 

 

[207WF]

I have the high oil temp problem, too. Like yours it did not start right away when the plane was new, but came on after maybe 100 hours. I have tried everything Roger suggests, but no joy. We have swapped out the guage and sender, getting the same numbers. I have to reduce power in the climb in the summer, often clawing my way up at only 200 ft/min or so to keep the oil below 250 (I won't let it go any higher than that). WF

[Roger Lee]

Hi Wayne,

 

Since you are at sea level you could go to the #4 clip position on the carb needle which will give you better cooling. If you don't like it you can go back.This can happen with sea level planes when it's hot outside.

[Ed Cesnalis]

I have the high oil temp problem, too. Like yours it did not start right away when the plane was new, but came on after maybe 100 hours. I have tried everything Roger suggests, but no joy. We have swapped out the guage and sender, getting the same numbers. I have to reduce power in the climb in the summer, often clawing my way up at only 200 ft/min or so to keep the oil below 250 (I won't let it go any higher than that). WF

 

I have the same experience. I think the only fix is a higher capacity cooler.

[Roger Lee]

Things I normally reserve for high temps. If you have an oil return line that "S" bends back behind the engine mount, re-route it out to the left under cyls 2-4 and then to the in port on the tank. This will take a new 90 degree fitting for the hose to the tank because the one they use now is straight. The tank will need to be turned about 60 degrees and the hose the out hose to the radiator will need to be slightly longer. Adjust the radiator brackets to make sure the radiator is as close and flat to the opening in the cowl as possible. You may even need to bend them slightly. Make sure you're using a K&N air filter and not a paper one. Move the needle clip down one notch on the carb needle to richen the mixture slightly. This usually drops the EGT's about 80F.

You can try using header wrap to help cooling within the cowl, but I'm not sure how much this might help.

Other things that will may help are zero flap departures (flatter climbs and higher speeds). If you use 15 flaps then flatter climbs and more speed.

 

One thing listed may not cure the problem, but all things should make a difference.We are only talking about lowering high oil temps by about 15-20F.

[mocfly]

Ct,

The oil cooler on out CT's is the largest one available without going to the xtra large cooler offered with the "glider tow package", not sure what the increase is.

 

Aside from that, I believe I have engineered the perfect fix for those who have this issue. I have made all the engineering drawings in Solidworks, come up with a bill of materials and have test data to show it will work. I will be bringing all this information to Oshkosh with me and plan on speaking to the FD guys about it. I would like to see a Fleet Approval on this mod so those long suffering can have some relief.

 

[Ed Cesnalis]

Chris,

 

I wish you success.

[mocfly]

Ct

Thanks. I believe that if given the data along with the engineering they should allow for the modification. Whether or nt ech individual person has to ask is another story. I am going to push for a fleet approval so ALL CT OWNERS that have this issue, such s yourself can get ome relief.

We will see.

 

[techman]

A post in 2010 talked about this problem. A pilot from Austrailia with an MC added cowl flaps to his plane and the problem went away. Another gentleman in South Africa did the same thing and claimed 15 deg C cooler temps in climb and no more "step climbing". The idea was that "The problem comes about because under most flight attitudes the cowling is "pressurized" because the hole for the exhaust and the cooling air outlets are inclined to the relative airflow."

 

While this sounds plausible to me I would think that if this were the case wouldn't every plane have this problem?

 

Any way here is the post from 2010

 

http://ctflier.com/index.php?/topic/322-oil-temp-problems-with-mc/

[mocfly]

Techman,

I have had many exchanges with one of the parties regarding the oil temp issue, and it is a combination of his modification along with my own that has brought forth a perfect engineered solution.(at least that's my opinion) I will be bringing all of my data with me in the hopes of sitting down with the guys at Flight Design and getting a fleet LOA for the mod. This knock on our aircraft really needs to go away.

[S3flyer]

Chris -- is your proposed change CT-specific or does the concept apply more broadly?

[mocfly]

S3,

All of my design was done with the Rotax 912 and our cowl. However I believe it can be applied to other aircraft running the 912....I sent an email with design ideas to some guys building the RV-12..

Interesting that they also have problems from time to time...Not all the -12's have the hot oil temp, just like us...it's more about how the engine oil cooling is right on the edge in both designs. One little difference and you have a problem.

Are you having issues?