English French German Italian Portuguese Spanish Swedish

 

Oil Temp Increases on 912UL

  • indaloamman
  • indaloamman's Avatar Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
3 years 7 months ago #10093 by indaloamman
Oil Temp Increases on 912UL was created by indaloamman
After I installed the larger Rotax oil cooler on my Zenith 701 with a 912UL (about 350 hours) the oil temp was dependably never about 190F. Flights were first in hot/humid conditions in Florida and now central Africa. Pressure would start off in the 60s, and settle at 53 or so. These conditions (180-190 and 53 psi) seemed like benchmarks.

About three weeks ago I was climbing from 2000MSL to 3000MSL and the oil temp drifted up to 230F, and did not reduce after I stabilized at altitude.

The high oil temp issue now occurs every time I fly. Yesterday in a test flight the oil temp rose above 240, and the pressure dropped to the 40s, maybe due to viscosity issues at the higher temperatures. Quick return to the airport.

In what may be a separate issue, I experienced diminished climb performance. Yesterday, after renewing air filters and making certain plugs were cleaned and gapped properly, I did see some improvement, reaching 750 fpm at DA of about 2500.

Ideas about courses of action welcomed!

Please Log in or Create an account to join the conversation.

  • indaloamman
  • indaloamman's Avatar Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
3 years 7 months ago #10095 by indaloamman
Replied by indaloamman on topic Oil Temp Increases on 912UL
Also, forgot to note that there is now a 200-300 degree delta between the EGTs, but one of these shows very erratic temp traces so i assume a sensor (grounding or wiring issue)

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
3 years 7 months ago #10096 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
What is the out side air temp?

One thing I always think of when something changes after maint. is what did the mechanic work on that may cause this issue?

Oil temps that climb to 230F-240F are not uncommon in hot climates. We have the same issue here in Southern Arizona during the spring and summer months. They should however go back down to somewhere between 215F-220F during a flat and level flight after about 10-15 minutes in a hot climate. Oil pressures seem to be between 45-55 psi. Most of the people I know seem to be using Aero Shell Sport Plus 4 oil
(10-40W). What I have found with many of the high oil temps around 240F-250F on climb is a reduced radius in one of the 13mm (1/2") oil hoses. Many have been the hose that comes off the oil cooler and goes into the oil pump housing. The other I have seen is the return line off the bottom of the engine back to the tank. The fix for this was quite easy. I took a 1/2" OD spring and inserted it into the hose where it made a bend. Now when the hose bends it keeps its full open radius and doesn't slow oil flow. When the hose gets hot it reduces it radius and slows the oil flow making temps hotter. I have now fixed maybe 20 aircraft with this technique and know others that have used it with success. Works for coolant hose too. I personally had 1 year old engine this happened to out of the blue. One day I was at 230F on climb out and then one year later I had a couple of flights that went up towards 245F+. I inserted the spring and I never see over 230F on a climb on a hot day any more and have about a 210F-220F during flat and level flight at 5200 rpm. Most people I see add the spring drop 15F-20F in temps.


Oil pressure drops can be a poor ground for the sending unit or a bad sending unit. These two are the most common. Higher oil pressures on start and then dropping after operating temps are reach is normal. If the pressure goes up and down with throttle then take a hard look at the grounding.

The wide gap in EGT temps could be the same as the oil, but more likely it could be a difference in fuel to each carb. Have you synced the carbs recently? Is the mag drop fairly equal between the ignitions?
Double check all the plugs that you installed and make sure you didn't accidentally pull an ignition wire slightly out of the boot, but this should show up in the mag check..

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

Please Log in or Create an account to join the conversation.

  • indaloamman
  • indaloamman's Avatar Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
3 years 7 months ago #10113 by indaloamman
Replied by indaloamman on topic Oil Temp Increases on 912UL
OAT here is 85-95F. Thanks for the tip on the springs--will give that a shot. Have not synced carbs in since the aircraft was first flown in late 2013, so I will do that. Mag check drop is minimal and equal. Using Aeroshell Sport Plus 4.

Will revert in 3 weeks--traveling soon. Many thanks for your suggestions.

Please Log in or Create an account to join the conversation.

  • indaloamman
  • indaloamman's Avatar Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
3 years 7 months ago #10114 by indaloamman
Replied by indaloamman on topic Oil Temp Increases on 912UL
Roger, quick one--is there a spring recommendation--somewhat overwhelmed by choice and not sure what is appropriate. tsk...

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
3 years 7 months ago #10117 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
Hi Adam,

A 230F oil temp at take off climb rate, WOT with an OAT of 85F-95F is quite normal. I would think that after you level off and maybe reduce throttle to 5100-5200 that the oil temps would drop 10F-15F to around 215F-220F on a hot day. I live in the same hot dry climate. The springs are 1/2" OD and are usually 5"-7" long. Nothing special about them. I do use stainless, but in an oil bath and given your more remote buying opportunities a standard steel spring would work. If you need to use two of them because of length and or the area of the bend that won't hurt a thing.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

Please Log in or Create an account to join the conversation.

More
1 month 2 weeks ago #20102 by udih
Replied by udih on topic Oil Temp Increases on 912UL
Hi Roger,
do you install the spring inside the hose or just insert the hose into the spring to keep the Curve strong?
I just wonder, if inserting the spring into the hose couldn't reduce the oil flow as well

I also have a high oil Temp issue.. at 4150RPM (during a flat and level flight ) I get 105-115c (OAT 30C) while my friends gets around 90C at exact same time and same aircraft&engine

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
1 month 2 weeks ago - 1 month 2 weeks ago #20103 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
Higher oil temps may be caused by other issues. Over pitched prop. What is your WOT in level flight? Poor air flow through a cowl and or though the oil cooler. Crud built up in the oil cooler (needs flushing). Do the temps go down if you cruise at 5000-5300 rpm?

If you don't have a reduced radius hose then just adding a spring will not help anything.
I put the spring inside the hose. I have been doing it for 15 years like this. I get to see every 5 or so years these springs at hose changes and they all look like new. I just push the spring inside the hose where the bend is. We're not talking too ridged thick heavy duty spring. Just a loose wide coil easy to bend spring. It just keep the diameter of the hose open so you don't get a reduced radius at the bend. I've never seen temps ever go up because of a spring and they have always gone down if the reduced radius area was an issue.I'm just finishing a Remos and had to install two springs in two of the 17mm coolant hoses to keep them from pinching down.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
Last edit: 1 month 2 weeks ago by Roger Lee.
The following user(s) said Thank You: udih

Please Log in or Create an account to join the conversation.

More
1 month 2 weeks ago #20118 by udih
Replied by udih on topic Oil Temp Increases on 912UL
Hi Roger, I'm not sure if the Temp at 5000-5300 rpm go down (but in my PPG this RPM its not cruise but climbing:-) )
I'll check this

The highest temp is during cruise flight at 4150RPM, but it comes after 15-20 min of flight (105-115C)

Exceptional temp reading comes before I shut down engine after landing, last flight it goes to 117C (OAT 29C)

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
1 month 2 weeks ago #20119 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
Hi Udih,
What type of aircraft are you flying with such a low rpm in cruise? Most of us in airplanes use 4100 as we approach a pattern or in the pattern.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

Please Log in or Create an account to join the conversation.

More
1 month 2 weeks ago #20120 by udih
Replied by udih on topic Oil Temp Increases on 912UL
I'm flying PPC:
powrachute.com/airwolf/

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
1 month 2 weeks ago #20123 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
A PPC. That explains it.
Thanks

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

Please Log in or Create an account to join the conversation.

More
1 month 2 weeks ago #20127 by udih
Replied by udih on topic Oil Temp Increases on 912UL
So what else could be the reason to the high oil temp?

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
1 month 2 weeks ago - 1 month 2 weeks ago #20129 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
Ask yourself if any of these may be a contributing factor.
Over pitched prop. Any thing at WOT in level flight under 5500 rpm is over pitched and the lower the WOT rpm the worse it is. For you that would be a little tougher to determine, but know what the take off climb WOT is would tell you.
Any oil hose with a tight bend that slows oil flow.
An older oil cooler that may need flushing.
Blocked air flow to the oil cooler.
Just had one in my shop: Too small an ID of oil hose which slows the flow.


With a Powered Parachute and an open air engine I would think temps would be in good shape. Temps can run a little warmer in the mid 4K's.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
Last edit: 1 month 2 weeks ago by Roger Lee.
The following user(s) said Thank You: udih

Please Log in or Create an account to join the conversation.

More
2 weeks 3 days ago #20421 by udih
Replied by udih on topic Oil Temp Increases on 912UL
I still have an oil temp issue..
On my last flights I realized that the oil temp goes up when I Reduces rpm speed and go down a little when increase...
The Worst I got is 130C..in 4300RPM and when reduced speed (even to 2000) it doesn't go down...

my oil cooler installed under the engine level in my PPC so it is getting airflow but not free
Should I try to move the cooler over the engine where it gets free air?

another issues I found:
In MAG check there is a different of 280 RPM + Light oil leakage in rear oil return zone
Is that could say something about oil temp?

Please Log in or Create an account to join the conversation.

  • Roger Lee
  • Roger Lee's Avatar
  • Away
  • Administrator
  • Administrator
More
2 weeks 3 days ago #20425 by Roger Lee
Replied by Roger Lee on topic Oil Temp Increases on 912UL
266F is fairly hot. You may not be getting good cooling because you're flying so slow and the air flow as you described is being obstructed. If it can be moved to an open air flow area it could help. A test would answer that question. The slower you went the less air flow. Almost like pilots sitting on the ground for long periods. No real air flow.
You should not have a 280 rpm mag drop differential. You do need to look at trouble shooting that and it is probably something minor.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
The following user(s) said Thank You: udih

Please Log in or Create an account to join the conversation.

More
2 weeks 2 days ago #20434 by udih
Replied by udih on topic Oil Temp Increases on 912UL
Is it a problem to install the oil cooler above the engine?
I saw a scheme in Rotax manual installation, that give this solution as an option, and just some lines after that, it was written: "the oil cooler should always installed below the engine oil pump"...

Please Log in or Create an account to join the conversation.

More
2 weeks 1 day ago #20443 by PeterKl
Replied by PeterKl on topic Oil Temp Increases on 912UL
An installation above the engine may „help“ to collect and/or keep air in the cooler. That‘s the opposite of what you want. Thus keep it below the engine (the installation manual is a sound source of information).

Please Log in or Create an account to join the conversation.

More
2 weeks 1 day ago #20446 by garrett
Replied by garrett on topic Oil Temp Increases on 912UL
Could you add a electric fan on the oil cooler?

Please Log in or Create an account to join the conversation.

More
2 weeks 11 hours ago #20449 by udih
Replied by udih on topic Oil Temp Increases on 912UL
Why did you say it's the opposite? I need the cooler be more cold cause I have higher oil temp
installation above the engine give it more air flow

Did I miss something? :-) or you confused :-)

the question was : Is it ok to install the cooler above the engine oil pump or not

Please Log in or Create an account to join the conversation.