Oil temp too high?

[bonal]

I know there has been much on the subject but I'm posting as specific to my temp. First before I had the cluster overhaul I was at 180 but I think that was just a stuck indicator. After OH temp would peg at redline after just a few minutes this was traced to a bad connection at the sending unit and fixed sending unit was also tested to be fine. So now I am seeing a gauge that appears to be functioning fine but temp is at around 220 still green but close to the edge. My pressure at cruise is just under 75 and CHT is between 350 and 375. So am I too hot and if so what should I be looking for. On an O360 with the screen where is the Vernatherm located and can an oil cooler just get gummed up with thousands of hours crud build up that it prevents good heat transfer. Thanks in advance for any suggestions 

[Yooper Rocketman]

I just posted on another thread the importance of an engine monitor.  

I have found a pile of useful information from my engine monitor, on both my Mooney's and on the two Bonanza's I flown.  I know there's some cost, but hate to say I think they are essential equipment today.  I even recently found the engine monitor tach was reading 100 RPM's lower than my mechanical tach (which should be almost bullet proof), and upon a check by my IA, we found the engine monitor was the one reading correctly.

[par]

To echo the response above, I too agree after spending the dough for one against my willingness. High indicated oil pressure was one of the primary reasons I went this route. As it turned out, it was the gauge that was at fault and that was easily confirmed by the engine monitor. 

[M204ever]

18 hours ago, bonal said:

On an O360 with the screen where is the Vernatherm

There is no vernatherm, there is an oil cooler by-pass valve just above the screen housing under the plug of the boss.

If you like a vernatherm you need to convert to spin-on oilfilter adapter Get Lycoming SSP 885-2, it gives you all of the information you need to make the change.

[Guest]

3 minutes ago, M204ever said:

There is no vernatherm, there is an oil cooler by-pass valve just above the screen housing under the plug of the boss.

If you like a vernatherm you need to convert to spin-on oilfilter adapter Get Lycoming SSP 885-2, it gives you all of the information you need to make the change.

Unless it has the vernatherm valve in the end of the screen housing.  I have a basket of them left over from filter conversions.

Clarence

[bonal]

OK I know that a full blown monitor system is preferred but since I just had the gauge serviced and calibrated And the sending unit tested to be good I'm thinking the temp is pretty close it heats up to just a nudge under the 220 mark so assuming this is correct is that too high?  I think there is a Vernatherm on the back of the screen housing so perhaps this needs to be tested. As I mentioned above CHT is just below 375 and pressure at 75 both of these gauges were also just rebuilt and calibrated. I'm thinking of 2 things I might do that won't break the bank first install a spin off filter as it will increase my capacity also JPI has a certified digital temp gauge that is also affordable. I would like to use it in addition to the existing temp since I don't like having inop placards on my panel. 

[N201MKTurbo]

Does it stay at 220 during cruise? Here in the hot land hitting 220 on climb out is not unusual. My current J will settle back to 180 ish in cruise. My old F model would run a bit higher.

Next time you have your oil screen off for cleaning inspect the vernatherm seat. If it has a ring wore in the cone you might want to replace it. If there are any nicks or scratches in the seat on the engine side, Lycoming has a reamer you can use on the engine to clean it up in place. My local engine shop loaned me the tool a few years ago and I did it. It only took a few minutes and helped a little.

[Bob_Belville]

Just now, N201MKTurbo said:

Does it stay at 220 during cruise? Here in the hot land hitting 220 on climb out is not unusual. My current J will settle back to 180 ish in cruise. My old F model would run a bit higher.

Next time you have your oil screen off for cleaning inspect the vernatherm seat. If it has a ring wore in the cone you might want to replace it. If there are any nicks or scratches in the seat on the engine side, Lycoming has a reamer you can use on the engine to clean it up in place. My local engine shop loaned me the tool a few years ago and I did it. It only took a few minutes and helped a little.

We sent the vernatherm base to our friendly engine shop who reamed the seat and returned in in a couple of days. My A&P does a lot of business with him and I don't think he charged us. 

We had previously sent the cooler to Pacific along with the vernatherm valve seeking better oil temps. Meanwhile I tweaked the baffle seals about every time I had the top cowl off. I kept finding gaps I could close off with RTV. 

In my case I think it was just a combination of smaller factors. During my last 6 flights MRN-M40-QQQ-ERV and return oil temps never hit 200 even in climb. With the OAT we had I think we'd have seen 220+ in cruise climb and I would have had to crack the cowl flaps to keep OT below 200 in cruise @ 75% power. 

[N201MKTurbo]

I have found the best way to flush the oil cooler is to use a parts washer. Drain as much oil from the cooler as you can by twisting it every witch way until you can't get any more oil to drain out. Then fill it about 3/4 with solvent and turn it every witch way to try to wash as much oil out as you can. Drain this oil rich solvent into a waste container. Next stick the flexi tube from the parts washer into one of the fittings and let it pump solvent through the cooler for 10 min or so. then stick it in the other fitting and let it pump for another 10 min or so. Then drain as much solvent as you can from the cooler. Next blow it out with compressed air until no more solvent spittle comes out of the cooler. blow the compressed air both directions.

FWIW, I have never seen this have a significant impact on oil temperatures.

Cleaning the outside of the fins, straightening the fins and making sure the baffling is good has the most effect.

I found on my old F model that flying through the rain would bend all the fins over and restrict the already poor airflow.

I used a dull pair of 3C tweezers to straighten the fins along with a good dose of patience.

Adding a Laser cowl closure improved the oil temps quite a bit.

[Yooper Rocketman]

1 hour ago, bonal said:

OK I know that a full blown monitor system is preferred but since I just had the gauge serviced and calibrated And the sending unit tested to be good I'm thinking the temp is pretty close it heats up to just a nudge under the 220 mark so assuming this is correct is that too high? . 

Bonal,  When you "calibrated" the gauge, did you actually install the sender in oil or water, heat it up, and verify the temp on the gauge is reading the same as what the actual temp was at the sender?  I used to do that a lot back in the 70's-80's on OTR trucks.  I had a metal cup with a pipe coupler welded to it that I would screw the sender into, wire it up and ground it, and use a propane torch to heat oil or water in the cup.  Now a days with IR guns so cheap, I use that a lot to verify temps.  You could shoot the oil pan right after landing and see how the IR reading compares to the gauge.  I'm with Bob, 220 degrees not too bad in climb, but too much IMHO for cruise.

41 minutes ago, N201MKTurbo said:

Cleaning the outside of the fins, straightening the fins and making sure the baffling is good has the most effect.

I found on my old F model that flying through the rain would bend all the fins over and restrict the already poor airflow.

I used a dull pair of 3C tweezers to straighten the fins along with a good dose of patience.

I bought one of these maybe 35 years ago.  I would imagine they are still available for any good tool supply.  I've used it a lot over the years and it reduces the time to straighten fins a bunch.  You can see there are several "fins per inch" options on the tool.

 

[tony]

Bonal, do you have the LASAR STC where the oil cooler has been relocated to the baffle behind the number 4 cylinder?

[bonal]

Took it out today OAT about 80f 220 in climb 400CHT pressure rock solid on 80 once in cruise CHT comes down to 370 pressure stays at 75 but OT never comes down even with a reduction in MP to 20 and RPM at 2400 stays at 220 with C flaps wide open. When I had the garwin cluster overhaul a few weeks ago the gauges were calibrated then but not on the airplane. I am going to find out if this is instrument or actual and then fix the problem. 

[bonal]

3 minutes ago, tony said:

Bonal, do you have the LASAR STC where the oil cooler has been relocated to the baffle behind the number 4 cylinder?

Sadly that mod does not apply to the C model was one of the first things I looked into

[bonal]

4 hours ago, Hyett6420 said:

FWiW read the thread I have going on baffles in Annual guess the AMUs?  A lot of advice has been given to me over re keeping the oil temp down.

Andrew

Yes I have but then I read all the threads. 

[bonal]

So my first task is to just confirm gauge accuracy. I have ordered a thermometer with a 16 inch probe this should reach into the top 2 inches of oil level in the dip stick tube. Once I confirm thermometer accurate I intend to insert it into the oil tube to take a measurement. My question is how long after shutdown does it take for the majority of oil to accumulate in the sump allowing me to reach the top of the oil to get a read.

[Guest]

7 hours ago, bonal said:

So my first task is to just confirm gauge accuracy. I have ordered a thermometer with a 16 inch probe this should reach into the top 2 inches of oil level in the dip stick tube. Once I confirm thermometer accurate I intend to insert it into the oil tube to take a measurement. My question is how long after shutdown does it take for the majority of oil to accumulate in the sump allowing me to reach the top of the oil to get a read.

The oil in the sump will be a different temperature than the location in the oil screen or filter housing. Simply remov the temperature thermocouple from the engine and boil it in a tin can full of water with your thermometer to confirm accuracy.

Clarence

[bonal]

Thanks doc I was just hoping to not have to remove all those darn screws. I knew that is the right way to go. Oh well 

[tony]

10 hours ago, bonal said:

Thanks doc I was just hoping to not have to remove all those darn screws. I knew that is the right way to go. Oh well 

I must be missing something,  Mine just screws out of the oil adapter. 

[Guest]

27 minutes ago, tony said:

I must be missing something,  Mine just screws out of the oil adapter. 

I believe he is referring to the hundred or so screws to remove the engine cowls.

Clarence

[Bob_Belville]

13 minutes ago, M20Doc said:

I believe he is referring to the hundred or so screws to remove the engine cowls.

Clarence

Slightly hypertbolic. 

[bonal]

35 minutes ago, M20Doc said:

I believe he is referring to the hundred or so screws to remove the engine cowls.

Clarence

Yep

[bonal]

Went to heat test the probe/gauge but did not have a fresh crush washer so didn't want to open it up till we could put it back together correctly try again Monday 

[jetdriven]

Heat the crush washer to cherry red and then it's annealed to be re-used. 

[Guest]

5 hours ago, bonal said:

Went to heat test the probe/gauge but did not have a fresh crush washer so didn't want to open it up till we could put it back together correctly try again Monday 

Most times its an MS35796-11 or an AN900-10.

Clarence

[1964-M20E]

Bonal try this take your oil temp probe remove from the engine leave the electrical connection to the plane and put it in an oil bath with a hot plate and your new independent thermometer heat up it about 200F get it stabilized and then check the cluster gauge.  This way you do not have to worry about different temps in different places.  This will tell you what is going on.  To do an accuracy check on the new thermometer do an ice bath check for 32F and a boiling water bath and check for 212F.