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Hot oil temps

Janekom

Janekom

Well Known Member
Patron
A friend's 10 did it's maiden flight today here in South Africa! Everything fine, but oil temp went up to 240 degrees C! He has used the standard oil cooler form Vans. The advise given to him now is to install a second oil cooler on the right side of the cooling baffles. What is the general feeling out there? Vans plan or extra oil cooler?
Much appreciated.
Jan.
 
Jan, some more info on the engine and install might help. Is it injected or carb? Before you go installing a second oil cooler make sure you have good airflow to and across the current oil cooler. It is all about airflow across the cooler, and if it's not there, a second oil cooler won't help.
How ere the cylinder head temps? How long was the flight and at what power settings>

Vic
 
Sorry guys. I should have given more info. This RV10 is as standard as can be as per Vans plans. Lyco IO-540 with Hartzell prop. This is the fourth RV this friend has built so he he knows what to do, but this is the first RV10 he did. Anyway he will go through everything again.
 
RV10inOz said:
Check the temp sender is working correctly!
Click to expand...

Yep - in particular, if you have the sort of oil temp sender included with Dynon and your battery is in the rear, then if the ground between the Avionics bus and the sender (e.g. thread sealant inhibiting connection or poor ground strap connections) then the sender will read "high" in proportion to the total resistance. I bought a 20 year old plane and upgraded to a Dynon, and the oil temps read as much as 50 degrees "hot" due to a corroded ground attach bolt.
 
hi temps

...I'm sure the 'real' mechanics will chime in anytime...
ensure you've plumbed the cooler bottom flow to top, that you don't have an 'air lock' etc. If you're 'breaking in' or running lean, you'll see elevated temps.......but they'll come down.
Fluid (air) dynmics suggest flow can be doubled by using a curved inlet and outlet lip.
..in short, exhaust all the options before adding the weight and plumbing of a second cooler!
best of luck!
 
Hi All,

I was (am) the test pilot.

As stated by Jan, the aircraft has a Lycoming IO-540.

The oil cooler is 100% as per the Van's installation instructions, fitted below the number 6 cylinder with the air feed from the baffle behind no 6.

We are using a temp probe supplied by Van's for the IO-540, being read by the MGL Odyssey glass panel.

We have not checked the probe yet but I can tell you that the oil got HOT.

The motor had run for 45 minutes on a bench prior to take off. Take off normal, CHTs initially all went to around 435. Kept the speed up and mixture rich and within about 15 minutes 4 of them were just below 400 deg and 2 just above - perfect for a new engine!

The oil temp gradually rose to 236 degrees after around 20 minutes into the flight. I joined the circuit to land and as I slowed on final approach, the temp rose to 242 degrees. Just prior to shut down after a short taxi it peaked at 243.

We have 6 10s flying in SA. Two have added another cooler and the problem has gone away.

A third cannot maintain full power (70 hrs on the engine) without the temps exceeding 230. We are planning another cooler into this one as well.
 
ZU-RVZ said:
Hi All,

I was (am) the test pilot.

As stated by Jan, the aircraft has a Lycoming IO-540.

The oil cooler is 100% as per the Van's installation instructions, fitted below the number 6 cylinder with the air feed from the baffle behind no 6.

We are using a temp probe supplied by Van's for the IO-540, being read by the MGL Odyssey glass panel.

We have not checked the probe yet but I can tell you that the oil got HOT.

The motor had run for 45 minutes on a bench prior to take off. Take off normal, CHTs initially all went to around 435. Kept the speed up and mixture rich and within about 15 minutes 4 of them were just below 400 deg and 2 just above - perfect for a new engine!

The oil temp gradually rose to 236 degrees after around 20 minutes into the flight. I joined the circuit to land and as I slowed on final approach, the temp rose to 242 degrees. Just prior to shut down after a short taxi it peaked at 243.

We have 6 10s flying in SA. Two have added another cooler and the problem has gone away.

A third cannot maintain full power (70 hrs on the engine) without the temps exceeding 230. We are planning another cooler into this one as well.
Click to expand...

One piece of info not yet provided is what the OAT was at the time of the flight?
 
Hi All,

I also have the Odyssey in my RV-9 and initally the oil temps were way out of line. I have built some 12 Vans aircraft and never saw high oil temps. Upon further investigations I discovered that the oil temp probe was defective giving me temps some 40 Deg F higher than normal. The use of a IR Temperature device aimed at the cooler after a flight comfirmed my suspicions. A quick check is to remove the probe from the engine insert it in a container of boiling water and see what the Odyssey reads. Also be sure you have the proper setup information in the Oil temperature setup menu.

Good luck,

John Higgins
RV-9 N194JH
 
Mine were hot on the maiden flight and it turned out to be the ramps that go on the upper cowl were on an upper shelf in my garage. When installed the temps were normal.
 
oil temp

My rv10---standard IO540 with standard cowling but put in oil cooler from (http://www.aviationtechproducts.com/html/engine__parts.html)
and also have side louvers. Fly in Florida--in summer climbed to 17,000 feet, max oil temp of 200. during warm weather fly 75% power with temps of 180-185. During winter have installed a butterfly valve on scat tube (http://www.nonstopaviation.com/rv10-controller-cooler-p-14566.html) and maintain temps of 180's. oil cooler has greater cooling than vans and fits in same place. obviates need for 2nd cooler with weight, expense etc. works great. lbb
 
oil temp

don't remember what altitude temps were, but ground temp was 90's with high humidity. I can climb at any speed, low or cruise climb, and have no high oil temps. My only 'problem' was too cool in winter, and fixed that with the adjustable butterfly--which is cheap and easy to install.(rare in aviation to have good product that works well, is made well, and is cheap to boot!!) i suspect with "larger" single oil cooler you will solve problem, but if you add side louvers, you will not have temp problem even in desert (is it one or 2 ss's??) lbb
 
I'm workong on some temp issues as well

I've got 4.5 hours on an 290 HP IO 540, w/ James Cowl and Plenum, 1st and 2nd flight showed oil temps peaking @ 232. OAT 75F 4500 ft, 24.5 sq. I already have the airflow 2006X installed. I removed the left side heat muff and scat tubes, cut the bottom of the lower cowl forward 1" yeilding aprox 4.5 sq in increase in lower cowl exit area, and cleaned up some other obstructions in the lower cowl. 3rd & 4th flight showed oil temps peaking @ 215, OAT 70F 3500 ft 25 sq. The oil temp issue has been reported by several -10 builders, I know of 2 that have plumbed a 2nd oil cooler and it seems to have done the trick. I know of one builder that took extensive differential manometer (pressure) readings at various points in the lower cowl. they all consistently indicated that the lower cowl pressures were too high thus impeeding the flow of air through the oil cooler (complicated by Van's obtuse mounting of the O/C). I have spoken with several who have installed louvers, and it appears to me that this has consistently shown good results. I have concluded (?) that for the james cowl/plenum there is not enough exit area in the lower cowl and that is impeeding exit air and increasing the pressure. Several builders in this situation are also reporting CHT issues.
Today I finished installing louvers to the bottom of my cowl.

DSC07557.JPG


I'll fly again on Monday and report any changes.
 
Hot Oil Temps

This has been discussed many times in the past. I posted the exact same thread after a few flights. I would be careful jumping to two oil coolers right away.

My first thought is that 435 is pretty warm on your CHT's but may be normal when breaking in the engine. I rarely see over 405 now after doing some very detailed baffle sealing. You would think that a 1/4" hole would not do much harm but it does. Tim did a great write-up on this. Read his thoughts on this too (link below). I did not believe it would make a difference but I was shocked. I still have the stock Van's cooler and have never had an issue. My alarm is set to 215 and I will hit that once in a while on hot (95+ deg days) but my CHT will still be at 405. When I do hit 215 I just level out for a few minutes and then continue my climb.
I have heard great results with improved oil coolers as well.

Here are a few more threads on the same issue.

http://www.myrv10.com/N104CD/maintenance/20061022/index.html

http://www.vansairforce.com/community/showthread.php?t=31173&highlight=oil+temp

http://www.vansairforce.com/community/showthread.php?t=28227&highlight=oil+temp

http://www.vansairforce.com/community/showthread.php?t=18781&highlight=oil+temp

http://www.vansairforce.com/community/showthread.php?t=15854&highlight=oil+temp
 
Flew again today, little change in oil temps

Deems Davis said:
I've got 4.5 hours on an 290 HP IO 540, w/ James Cowl and Plenum, 1st and 2nd flight showed oil temps peaking @ 232. OAT 75F 4500 ft, 24.5 sq. I already have the airflow 2006X installed. I removed the left side heat muff and scat tubes, cut the bottom of the lower cowl forward 1" yeilding aprox 4.5 sq in increase in lower cowl exit area, and cleaned up some other obstructions in the lower cowl. 3rd & 4th flight showed oil temps peaking @ 215, OAT 70F 3500 ft 25 sq. The oil temp issue has been reported by several -10 builders, I know of 2 that have plumbed a 2nd oil cooler and it seems to have done the trick. I know of one builder that took extensive differential manometer (pressure) readings at various points in the lower cowl. they all consistently indicated that the lower cowl pressures were too high thus impeeding the flow of air through the oil cooler (complicated by Van's obtuse mounting of the O/C). I have spoken with several who have installed louvers, and it appears to me that this has consistently shown good results. I have concluded (?) that for the james cowl/plenum there is not enough exit area in the lower cowl and that is impeeding exit air and increasing the pressure. Several builders in this situation are also reporting CHT issues.
Today I finished installing louvers to the bottom of my cowl.

DSC07557.JPG


I'll fly again on Monday and report any changes.
Click to expand...

Well, thought I'd report on the results of installing the louvers. I flew again today for 1 1/2 hours MP 28-25 ", RPM 2500. Alt 3500-6500. and oil temps were pretty much the same 215-220,as were the CYL temps. It was about 5-6 deg C warmer at lower levels today. I haven't given up completely on the louvers, and am considering adding a partial set (8 louvers) per side just outboard of the two full sets. My theory is that the existing louvers are all in the 'tunnel' portion of the cowl, and may not be having much effect on the remainder (e.g. like where the oil cooler is located). I did install a baffle inside of the oil cooler wedge mount. I got it from Bill G @ Airflow, he says that their testing shows the most of the air entering the Van's oil cooler exits through the bottom portion of the cooler. This baffle splits the intake air and directs 1/2 of it to the upper 1/3 of the oil cooler. (sorry no pics today). I also did some major work sealing leaks in the plenum/baffles.
 
I also have IO 540 with cold air sam james cowl and Barrett engine. We put 2 louvers on side and 2 on bottom and have not had probe with heat.
 
Their are now more than 200 RV-10's flying and only a hand full have extra louvers on the cowl to attain normal oil temps.
If the oil temps are severe in 65 degree temps (condition provided by original poster of this thread) then the underlying cause should be investigated before modifying the cowling.
 
higher oil temp

Had a perceived high oil temp with my new TMX360. Found my Dynon EFIS to be in error by as much a 30 degrees. Software update solved issue. Isn't 215 degrees nominal with a vernatherm equiped engine? And doesn't temps have to be above 212 to boil water off?
 
agough277 said:
Had a perceived high oil temp with my new TMX360. Found my Dynon EFIS to be in error by as much a 30 degrees. Software update solved issue. Isn't 215 degrees nominal with a vernatherm equiped engine? And doesn't temps have to be above 212 to boil water off?
Click to expand...

Water will evaporate at any temperature over the local dew point. Since blow-by contains a fair amount of water, the dew point in a crankcase can get fairly high, but anything over about 160F for 30 minutes or so should be sufficient. Higher is better, but the practical limit on the high end is the viscosity of the oil.
 
High Oil Temp possible cause

I have seen several instances of poor or no seal between the filter airbox assembly and the under spinner intake scoop allowing ram air that is supposed to all go into the carb or fuel injection throttlebody instead pressurizing the BOTTOM of the cowl, thereby reducing pressure differential and thus total airflow and causing high oil temps and CHTs. In all these cases (including one with NO rubberized attempt at making the seal) when decent seal was installed, dramatically lower oil temps and CHT's were realized. Remember, it's supposed to be high pressure on top of the cylinders, low pressure under. A huge gap in the under spinner scoop to engine carb/injection servo serves to counter that pressure differential that is supposed to force air down through the cylinder fins and also through the oil cooler. I used inner tube rubber attached to the carb airbox in a shape that cusps over the intake tube built into the under spinner scoop in a squeezing fashion that seals the joint quite well. Maybe this will help...Dan Maloney RV-4/ many different RV test flts.
 
high oil temp

I am building an -10 and I have considered not installing the louvers! I had a chance to inspect a few certified airplanes at the local FBO that had the cowlings removed. One thing that I noticed was how big the scat hose was going to the oil cooler compaired to the Vans installation. Maybe just a bigger scat hose would solve this. If you get a chance check out a Piper Cherokee -6 or Saratoga.
 
Ground Cable

breister said:
Yep - in particular, if you have the sort of oil temp sender included with Dynon and your battery is in the rear, then if the ground between the Avionics bus and the sender (e.g. thread sealant inhibiting connection or poor ground strap connections) then the sender will read "high" in proportion to the total resistance. I bought a 20 year old plane and upgraded to a Dynon, and the oil temps read as much as 50 degrees "hot" due to a corroded ground attach bolt.
Click to expand...

I have an Advanced Flight Systems EFIS/Engine monitor and even though I have a #00 ground cable from the engine case to the airframe I did not have a "proper ground" and my Oil Temp Indicator would go off scale on the high side. It all came back to normal after I changed the location of the ground cable.
 
High Oil Temps

Usually this is caused by poor baffling and or an oil cooler that is too small. Check the mark off on the upper cowling. If the baffles are black you should see black mark off all the way around the upper cowling. if you see gaps in the mark off then air is blowing around the baffle. Also make sure if the oil cooler is mounted on the baffling that you seal around it with high temp RTV.

For an oil cooler I recommend the large Stewart Warner. Call Pacific Oil cooler and they will have the exact cooler for the 10. Also check oil pressure and make sure its not adjusted too high.

Most of the time this is a baffling issue so start there.

Pat
 
Problem has been solved many times before

If you have a RV-10 or a Rocket, and you are using a Lycoming IO-540 engine, the oil cooling problems have all been solved many times before and the results posted to this site many times. I can understand the reluctance to make changes to existing, flying airplanes, but if you really want to fix the problem forever, you will need to make some changes.

First, DO NOT install your oil cooler on the firewall. Sorry, but that is an absolutely lousy place to put the oil cooler and a terrible place to try and re-direct the appropriate cooling air. I know, I know, some folks have gotten this to work and some production airplanes do this as well. You want to fix things right? So move the oil cooler to your engine mount on either the left or right side of the engine. I prefer the right side since there's more room between the baffle and the mount. Mount the cooler to the engine mount using cushion clamps and some custom made brackets made out of .063. Angle the cooler down slightly.

Now, build a plenum chamber off the back of the baffle and bolt it to the front of the cooler. Top and bottom of the chamber should not diverge more than 12 degrees lest you create turbulence in the plenum. You won't be able to cover the entire face of the oil cooler. Don't worry, you won't need all of it anyway. Use some chafe seal around the inlet to the oil cooler plenum to provide a tight seal.

Now, just doing this alone will not guarantee you cool oil. You have to have a tight fit of your baffle seals. Better yet, build a plenum for your engine if you haven't done this work yet. If you already have baffles, make sure the seal all around is good. You MUST build a ramp into the floor of the right baffle inlet area. You will be amazed at how much cooler your cylinders will be. That blunt edge where the air just rams into the face of the #1 cylinder just destroys the smooth inlet airflow. I did it on both inlet areas but the right is much worse than the left.

Do you have the ramps molded into the top of the cowling? If not, you need them again to smooth the airflow. Start these ramps as soon as you can just aft of the opening to maximize the size of the opening, particularly in the area between the cylinder and the top of the ramp. If this area is squeezed down too much, it will limit the flow and slow the air.

If you do these things, you will be partially blocking your oil cooler off most of the time because your oil will be too cool. Promise. You don't need another cooler and you don't need louvers. Every problem is unique, but typically, the problem turns out to be getting air to the cooler, not getting the air out of the cowling. Turbulence and leakage will rob you of the maximum cooling effect of the incoming air.
 
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Randy and others, thanks for all the advise and ideas. In the mean time the owner has opted to add the second oil cooler. The one that is included in the 7 kit was added on the RH rear baffles. This did drop the temps as expected, but after reading Randy's advise, I think I am leaning more his way. We are now nearly at the stage where we have to hang the motor and will have to decide soon.

I am just wondering if it is worthwhile trying to run a poll on this forum to find out what the trend is among the 160 or so flying 10s?
 
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