MikeOH Posted February 12, 2019 Report Share Posted February 12, 2019 I’d like to track down why my oil temps run high, 220 in the summer, a bit over 200 now (OAT 55). I have the Lycoming guide to troubleshooting high oil temps and one of the tests is to check the temp of the oil cooler compared to the sump (should be the same with no cool ‘spots’). So, after my flight today I shut down (about 5 minutes after landing with OAT around 55) and within a couple of minutes put my hand on the oil cooler and it was pretty much the same temp as the surronding cowling! That is to say, like 55 degrees! Am I on to something, or did my descent, landing, 5 minutes of taxiing allow the oil cooler to drop that much in temp? Thanks! Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 12, 2019 Report Share Posted February 12, 2019 1) IR thermometer from Harbor freight? 2) Testing the OilT thermistor in a pot of water? 3) Testing the temp sensitive oil flow control valve (there’s a name for that...) that is done in a pot of water as well... 4) Flushing the radiator is often done after the other devices are proven to work... 5) Inspect the oil cooler fins first... all open and not dirty? It can be cleaned as well... PP thoughts to get you started, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 12, 2019 Author Report Share Posted February 12, 2019 Yep. Those are the steps in the Lycoming document. Getting the Vernatherm out is a bit of a project, so I’m trying the simple stuff first. I have both the factory oil temp gauge and a G3 engine monitor with a separate thermistor; they agree pretty well, so I don’t think it’s a gauge problem. The cooler fins are open and clean. The IR thermometer is a good idea, but the cooler was not even warm after today’s flight. I’m trying to understand if that could be ‘normal’ after a low power descent and 5 minute taxi, or if it should still be at least warm to the touch. If it should be warm, then I’ve narrowed the problem to the cooler, lines, or Vernatherm. I’m hoping someone has some experience that I can draw on. Thanks! 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted February 12, 2019 Report Share Posted February 12, 2019 The oil cooler should be warmer than what you’re experiencing. It sounds like no flow to the cooler, failed vernatherm valve, or lack of flow to or thru the cooler. Clarence Quote Link to comment Share on other sites More sharing options...
Bob_Belville Posted February 12, 2019 Report Share Posted February 12, 2019 If you have an EDM from which you can download data you can plot the oil temp. The rising temp on climb out should show a change in the slope of the curve when the vernatherm closes at about 185F directing oil through the cooler. Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 12, 2019 Author Report Share Posted February 12, 2019 3 hours ago, M20Doc said: The oil cooler should be warmer than what you’re experiencing. It sounds like no flow to the cooler, failed vernatherm valve, or lack of flow to or thru the cooler. Clarence Thanks! That's just what I was wondering. I suppose the easiest thing would be to pull the cooler and send it out to Pacific Oil Cooler and see if that fixes the problem... Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 12, 2019 Author Report Share Posted February 12, 2019 1 hour ago, Bob_Belville said: If you have an EDM from which you can download data you can plot the oil temp. The rising temp on climb out should show a change in the slope of the curve when the vernatherm closes at about 185F directing oil through the cooler. Excellent idea! I'll pull the data tonight and see if there is a slope change. Quote Link to comment Share on other sites More sharing options...
1967 427 Posted February 13, 2019 Report Share Posted February 13, 2019 When I had a high oil temp indication, on landing I checked the oil cooler by touching it and found it dead cold. Being methodical I pulled the TC and placed it in boiling water along with a multimeter that has a thermocouple. Both multimeter and the aircraft gauge correlated. Next the vernatherm was pulled and placed in the same water, it didn't open, problem solved. It was replaced with a new 85C or 185F vernatherm. After the vernatherm was replaced, life was good. (now that I think about it the old vernatherm might have had an AD on it) 1 Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 13, 2019 Author Report Share Posted February 13, 2019 5 minutes ago, 1967 427 said: When I had a high oil temp indication, on landing I checked the oil cooler by touching it and found it dead cold. Being methodical I pulled the TC and placed it in boiling water along with a multimeter that has a thermocouple. Both multimeter and the aircraft gauge correlated. Next the vernatherm was pulled and placed in the same water, it didn't open, problem solved. It was replaced with a new 85C or 185F vernatherm. After the vernatherm was replaced, life was good. (now that I think about it the old vernatherm might have had an AD on it) Thank you! I’m wondering if I should just bite the bullet and pull the vernatherm; how difficult was it? It looks like a pain vs pulling the oil cooler. Quote Link to comment Share on other sites More sharing options...
1967 427 Posted February 13, 2019 Report Share Posted February 13, 2019 My is a 1966 M20C, as I recall, it was a piece of cake. I prepared it for my mechanic. Didn't have to touch either mag or prop governor, just pulled battery and battery tray. I might have also pulled oil filter, but wouldn't bet a lot of money on the oil filter. (FYI, I do have a gambling problem) Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 13, 2019 Author Report Share Posted February 13, 2019 1 hour ago, 1967 427 said: My is a 1966 M20C, as I recall, it was a piece of cake. I prepared it for my mechanic. Didn't have to touch either mag or prop governor, just pulled battery and battery tray. I might have also pulled oil filter, but wouldn't bet a lot of money on the oil filter. (FYI, I do have a gambling problem) Thanks, again! I’m going to pull the upper cowl and have a look. Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 13, 2019 Author Report Share Posted February 13, 2019 (edited) 12 hours ago, Bob_Belville said: If you have an EDM from which you can download data you can plot the oil temp. The rising temp on climb out should show a change in the slope of the curve when the vernatherm closes at about 185F directing oil through the cooler. Looking at several recent flights and I don’t see any change in slope...just ramps up to around 210 F. I’m beginning to think the vernatherm isn’t routing oil to the cooler... Edited February 13, 2019 by MikeOH Quote Link to comment Share on other sites More sharing options...
Bob_Belville Posted February 13, 2019 Report Share Posted February 13, 2019 10 hours ago, MikeOH said: Looking at several recent flights and I don’t see any change in slope...just ramps up to around 210 F. I’m beginning to think the vernatherm isn’t routing oil to the cooler... There are several possibilities. The vernatherm may be bad, the vernatherm valve seat may need resurfacing to get a tight seal, or it is also possible that the seat has been reamed so deep that the travel of the v'therm valve stops short of making a tight seal. https://www.lycoming.com/content/understanding-oil-flow Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 13, 2019 Author Report Share Posted February 13, 2019 1 hour ago, Bob_Belville said: There are several possibilities. The vernatherm may be bad, the vernatherm valve seat may need resurfacing to get a tight seal, or it is also possible that the seat has been reamed so deep that the travel of the v'therm valve stops short of making a tight seal. https://www.lycoming.com/content/understanding-oil-flow Bob, As I don't have the history on the seat and valve (logbook doesn't have anything noted, but I'm not betting that everything was recorded!), those are excellent suggestions to check. I never would have thought about the seat being reamed too many times and, therefore, too deep. I'd really like to get this solved before warmer weather rolls around... I was pushing 230 F last summer Thanks for the link, very informative! Quote Link to comment Share on other sites More sharing options...
orionflt Posted February 13, 2019 Report Share Posted February 13, 2019 If you pull the filter you will have easy access to the vernatherm. 1 Quote Link to comment Share on other sites More sharing options...
Bob_Belville Posted February 13, 2019 Report Share Posted February 13, 2019 My OT has improved with the last modification of the SabreCowl but if I see temps over 220F again this summer my next effort will be to replace the oil filter adapter. I've already swapped out oil coolers, replaced the vernatherm, and had Triad resurface the valve seat. Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 13, 2019 Author Report Share Posted February 13, 2019 3 hours ago, orionflt said: If you pull the filter you will have easy access to the vernatherm. That's a good idea. I was thinking of coming in from the side, but with the filter removed it would be easier access. Quote Link to comment Share on other sites More sharing options...
MikeOH Posted February 13, 2019 Author Report Share Posted February 13, 2019 3 hours ago, Bob_Belville said: My OT has improved with the last modification of the SabreCowl but if I see temps over 220F again this summer my next effort will be to replace the oil filter adapter. I've already swapped out oil coolers, replaced the vernatherm, and had Triad resurface the valve seat. Sorry to hear all of those 'fixes' were not completely effective I'm a bit concerned that maybe my situation, as well....no new cowl, but I did replace the baffles which helped a little (helped my CHTs a bit more) Quote Link to comment Share on other sites More sharing options...
orionflt Posted February 13, 2019 Report Share Posted February 13, 2019 1 minute ago, MikeOH said: That's a good idea. I was thinking of coming in from the side, but with the filter removed it would be easier access. you will get some oil spillage so have rags/catch pan underneath, depending on how many hours are on the filter it can be reinstalled. if you are close to an oil change, I would just do the oil change at the same time. Brian Quote Link to comment Share on other sites More sharing options...
MikeOH Posted March 1, 2019 Author Report Share Posted March 1, 2019 Wanted to get back with outcome. Turned out to be plugged oil cooler; vernathrem checked ok. Sent off to Pacific Oil Cooler. Decided on new oil lines/fittings just 'cause I was in there anyway Oil cooler is now getting hot and OT is stabilized at 180ish. Another AMU+... oh, well! 4 Quote Link to comment Share on other sites More sharing options...
carusoam Posted March 1, 2019 Report Share Posted March 1, 2019 Great follow-up, Mike! Did you see the sludge that came out? Any missing engine parts show up in the old hoses? Just wondering what that looks like... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
MikeOH Posted March 1, 2019 Author Report Share Posted March 1, 2019 Mechanic said it was 'a gray sludge'...no engine parts, but I wasn't missing any... I don't think Anyway, I should be all set for summer. I'm excited to see if my CHTs drop a bit; I'm always fighting #2 that will head north of 400 in a climb in warm weather if I don't back off power a bit. We shall see. 1 Quote Link to comment Share on other sites More sharing options...
Marauder Posted March 1, 2019 Report Share Posted March 1, 2019 Mechanic said it was 'a gray sludge'...no engine parts, but I wasn't missing any... I don't think Anyway, I should be all set for summer. I'm excited to see if my CHTs drop a bit; I'm always fighting #2 that will head north of 400 in a climb in warm weather if I don't back off power a bit. We shall see. Gray sludge sounds like lead build up. How frequently do you change the oil?Sent from my iPad using Tapatalk Pro 1 Quote Link to comment Share on other sites More sharing options...
neilpilot Posted March 1, 2019 Report Share Posted March 1, 2019 1 hour ago, Marauder said: Gray sludge sounds like lead build up. How frequently do you change the oil? Gray sludge sounds like synthetic oil. Quote Link to comment Share on other sites More sharing options...
MikeOH Posted March 1, 2019 Author Report Share Posted March 1, 2019 (edited) 3 hours ago, Marauder said: Gray sludge sounds like lead build up. How frequently do you change the oil? Sent from my iPad using Tapatalk Pro Never more than 50 hours. But, remember, this is what came out of my PLUGGED up oil cooler; no telling how long that 'oil' had been festering in there since I've had the plane for a year and a half and have always had the oil temp run high (i.e., oil cooler has been plugged the entire time I've owned). Log history does show the oil was changed at less than 50 hour intervals. Previous owner (for 13 years) ran, and I have continued to run, Aeroshell 100W+ Edited March 1, 2019 by MikeOH 1 Quote Link to comment Share on other sites More sharing options...
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