Jim Meade Posted January 1, 2015 Report Share Posted January 1, 2015 Are any of you using oil or water thermostats? Which ones? Are you satisfied with the results? Why did you decide to install one? Who installed it? Is it covered by an LOA or are you experimental? The intent of this thread is to discuss oil and water thermostats. If you would like to discuss whether they are necessary or appropriate, perhaps you would prefer to start a different thread to reduce the chances that this one will fall afoul of thread drift. Have any of you modified the shape or size of the air intake to the radiators? Have you relocated or segregated the radiators? If so, where did you mount them? Did you have to modify the cowling? Have any of you installed shutters or other methods of adjusting the air intake in flight? If so, please describe your installation and tell us how well it works and your level of satisfaction. TIA Link to comment Share on other sites More sharing options...
Anticept Posted January 1, 2015 Report Share Posted January 1, 2015 I don't recall seeing people using water thermostats, but I do know oil thermostats are popular. They significantly decrease the warmup time. EDIT: http://ctflier.com/index.php?/topic/3106-temperature-management/#entry41036 Link to comment Share on other sites More sharing options...
Roger Lee Posted January 1, 2015 Report Share Posted January 1, 2015 They use both thermostats (oil and coolant). Part of the problem in doing so is that most people don't know or understand that Rotax doesn't have a minimum CHT or coolant temp and it really doesn't help engine heating as much as most want to think. The coolant only cools the heads so the entire engine and very little oil isn't affected. The oil thermostat may help some, but when I'm warming up with them they might reach 120F oil temp about 1 minute before me without one. Flying is where the oil thermostat would help more and not during warm up with relatively little air flow over the radiators. The oil thermostat cost any where from $300-$500 for an install and it's a PITA to work around. Cost more during a hose change and only keeps temps to 180F-190F where a piece of 2" aluminum tape cost 5 cents and keeps my temps up at 205-215F and took me 1 minute to install it. How many winters would it take and pieces of tape to equal $500. Many who go through all the trouble of installing a coolant thermostat would swear it gives them great and quick results, but most of that compared to real research is more wishful thinking. You put it in it has to be faster and better. The digital instrument world has given us more data than most are used to and those same people don't know exactly what to do with all the data or interpret its data. Link to comment Share on other sites More sharing options...
N89WD Posted January 1, 2015 Report Share Posted January 1, 2015 Ball parked it Roger, as usual. Carry on. Link to comment Share on other sites More sharing options...
Jacques Posted January 1, 2015 Report Share Posted January 1, 2015 In MY case,,installing the oil thermostat [ Permacool ] greatly reduced the warmup time (in cold weather) . But it open at 180°F,so the 'tape on radiator' was still needed. I changed it for the ThermoStasis which open at 205°F but haven't tried it yet...but I think I still will need the tape. Having the coolant thermostat is not usefull on a CT, ...although, I have seen it (factory installed) on CTSW and CTLS. If I had a cabin heater working with coolant.. [ or carb heat using coolant ], I 'may' have one... Link to comment Share on other sites More sharing options...
Roger Lee Posted January 1, 2015 Report Share Posted January 1, 2015 If FD would have researched the coolant and CHT no minimum temp they might have seen it wasn't necessary. Link to comment Share on other sites More sharing options...
Anticept Posted January 1, 2015 Report Share Posted January 1, 2015 They use both thermostats (oil and coolant).Where is the coolant thermostat? EDIT: brainfart. It's the barrel thing on the left running from the coolant spider (reservoir assembly). Never messed with it and just now realized i have been thinking it was just a junction fitting since before I went to A&P school 3 years ago. Link to comment Share on other sites More sharing options...
Runtoeat Posted January 1, 2015 Report Share Posted January 1, 2015 The tape trick using two 1" strips of aluminum tape across my radiator works for most days here in Michigan. The later Fall and early Spring flying here can have temp swings of 50 to 60 degrees and sometimes requires me to add a third strip or remove one of the two strips to be in the optimum temp range. Before I bought my CT, I flew a Remos and this had a bowden cable controlled shutter for it's radiator. The Pros of this is it worked well but the Cons is the obvious need to monitor coolant and oil temps because CHT will climb fast when the radiator is completely blocked. I'm glad my 2006 CT doesn't have the oil/coolant thermostat system due to cost and weight of a system which falls short of getting the fluids up to good operating temps. One might suggest I install a engine heater kit but this doesn't provide warm ups when I fly and park for a few hours at other airports. All in all, I would like to have a shutter setup on my CT for faster warm ups during cold temps but this will not happen unless I convert my CT to experimental. Link to comment Share on other sites More sharing options...
Jacques Posted January 1, 2015 Report Share Posted January 1, 2015 Where is the coolant thermostat? EDIT: brainfart. It's the barrel thing on the left running from the coolant spider (reservoir assembly since a picture worth a thousand words Link to comment Share on other sites More sharing options...
Roger Lee Posted January 1, 2015 Report Share Posted January 1, 2015 Temps don't have to be exact. It's a range and so long as you are in the ballpark don't worry about them, especially if descending for a landing. Link to comment Share on other sites More sharing options...
Jim Meade Posted January 1, 2015 Author Report Share Posted January 1, 2015 Well, here we go. There are numerous thread on this and other sites about Rotax 912 water and oil thermostats and they usually end up being about what each poster likes and why the other posters should like the same thing. My hope here was simply to get people to post their results, per the OP. Let's try it again, please, without the advocacy which you can do in another post. What do you have and how well does it work? Thanks to those who have already answered per the OP. Link to comment Share on other sites More sharing options...
FastEddieB Posted January 1, 2015 Report Share Posted January 1, 2015 Cross-brand data point: My Sky Arrow came equipped with cooling fans and a baffle that's controlled from the cockpit: (clicking on it should give a larger, clearer view) No thermostat for oil or water are mentioned in the POH. The "Removable Radiator Shutters" shown was not delivered with the plane - maybe I should ask the dealer about that. Anyway, even with the baffle closed, warmup takes a long time in the winter and inflight temps are still very low on cold days: Even on hot days, I can close the baffle once in cruise and stay in the green. I do so since, in theory, I'd have a tiny bit less "cooling drag" with the baffle closed - though I don't think I've ever noticed a performance increase. For extra credit, anyone care to guess what the yellow line on the right of those three gauges indicates? Link to comment Share on other sites More sharing options...
WmInce Posted January 1, 2015 Report Share Posted January 1, 2015 . . . "anyone care to guess what the yellow line on the right of those three gauges indicates?" . . . Appears to be slippage marks for the instrument lens. Link to comment Share on other sites More sharing options...
Anticept Posted January 1, 2015 Report Share Posted January 1, 2015 Appears to be slippage marks for the instrument lens. Yup. Old school style instrument setup. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted January 1, 2015 Report Share Posted January 1, 2015 Coming home from Page in October about 7 years ago I learned a temperature lesson. I departed Page and couldn't stay warm without cabin heat and couldn't find a place to land for hours. When I landed in Tonopah I was hypodermic. Since EGT drives cabin heat I would have thought oil and coolant temps were unrelated but it worked instantly. As soon as I took off I had to land a 2nd time in the 40kt wind to remove some tape and then all temps were in the green and cabin heat was ample. Link to comment Share on other sites More sharing options...
FastEddieB Posted January 1, 2015 Report Share Posted January 1, 2015 Appears to be slippage marks for the instrument lens. Too easy! Note that they're only on the instruments with markings on the lens. Otherwise you might not be aware of the lens having rotated and all the markings being off. Good job! Link to comment Share on other sites More sharing options...
FastEddieB Posted January 1, 2015 Report Share Posted January 1, 2015 When I landed in Tonopah I was hypodermic. Are you sure you're not just needling us? Anyway, glad you didn't get stuck there! Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted January 1, 2015 Report Share Posted January 1, 2015 I had it spelled hypo-thermic then hypothermic. Then I fixed it with spell checker Link to comment Share on other sites More sharing options...
Philip Welsch Posted January 1, 2015 Report Share Posted January 1, 2015 My 2008 CTLS came from FD with both coolant and oil thermoststs. Pro: neither has failed (660 hrs). I expect they will eventually fail - closed. Con: The coolant thermostat apparently is not useful at all and the oil unit will not keep temp above 180 degrees without tape even here in SW New Mexico. Maint. is more difficult with the thermostats - some spark plugs are difficult to get to and as Roger mentioned hose change is more of a pain. Philip Link to comment Share on other sites More sharing options...
Anticept Posted January 2, 2015 Report Share Posted January 2, 2015 My 2008 CTLS came from FD with both coolant and oil thermoststs. Pro: neither has failed (660 hrs). I expect they will eventually fail - closed. Con: The coolant thermostat apparently is not useful at all and the oil unit will not keep temp above 180 degrees without tape even here in SW New Mexico. Maint. is more difficult with the thermostats - some spark plugs are difficult to get to and as Roger mentioned hose change is more of a pain. Philip The oil thermostat has a failsafe, it never completely closes for this reason. Had one of ours fail at 2,200 hrs closed, but it never overheated. Got close and the dynon fired off the warnings, but no overheats. As for worrying about the coolant failing closed: these engines will run even without coolant at all. It was demonstrated recently when a pilot had an aircraft with a flawed reservoir layout (the hose went in through the top, and only stuck through 2-3 inches. Coolant flows out, but not back into the system). It was run for 3 hours in a significantly overheated condition through rigorous touch and goes and other landing practice, and the pilot ignored the CHT thinking it was a faulty indication. The CHTs melted out of the cylinder heads, and now the engine is used as a training engine at leading edge air foils (it's a bitch because everything is warped). When the engine was removed from the aircraft, there was only a little bit of coolant left in the bottom hoses as most was boiled off. The pilot did not know until the next day when he/she did their runup and noticed significant difficulty in reaching rated power. This was one of the motivations for the newer cylinder heads having the CHT holes on top now, and they are in the water jacket instead of just in the block. By the time the engine gets hot enough to melt the CHTs, there's no water left anyways. Link to comment Share on other sites More sharing options...
Doug G. Posted January 2, 2015 Report Share Posted January 2, 2015 Not sure if that is correct as I have heard of two engines that are being used as tear downs for Rotax line maintenance (on of which was used in the class I took at LEAF) that had overheated enough to need replacement. They both ran low on water because only the overflow was checked, not the fill reservoir. You may get away with it for a while, but they are not invulnerable. Link to comment Share on other sites More sharing options...
Doug G. Posted January 2, 2015 Report Share Posted January 2, 2015 On the other hand, I don't know that the engine quit, or refused to start. Link to comment Share on other sites More sharing options...
Tom Baker Posted January 2, 2015 Report Share Posted January 2, 2015 The coolant thermostats do fail, and the engine gets hot real quick. I had to replace one on a airplane with 300 hours. The actual thermostat inside the housing is just like a automotive thermostat. The folks at FDUSA provided a part number for a thermostat from NAPA to use as a replacement. Link to comment Share on other sites More sharing options...
Anticept Posted January 2, 2015 Report Share Posted January 2, 2015 Not sure if that is correct as I have heard of two engines that are being used as tear downs for Rotax line maintenance (on of which was used in the class I took at LEAF) that had overheated enough to need replacement. They both ran low on water because only the overflow was checked, not the fill reservoir. You may get away with it for a while, but they are not invulnerable. That's the engine. The pilot only checked the reservoir, which was a cheap thin plastic bottle that almost looked like a water bottle. The hose went in through the cap and didn't go further than 2-3 inches. Over time, it emptied out the coolant system enough to where it didn't work, and it started getting hot enough to turn the coolant to steam when it started overheating. The coolant thermostats do fail, and the engine gets hot real quick. I had to replace one on a airplane with 300 hours. The actual thermostat inside the housing is just like a automotive thermostat. The folks at FDUSA provided a part number for a thermostat from NAPA to use as a replacement. Should find out if it can be replaced with a fail-safe thermostat (fails open). Although, I think I recall a discussion here that they don't actually work very well. Link to comment Share on other sites More sharing options...
Jacques Posted January 2, 2015 Report Share Posted January 2, 2015 SOME READING http://www.rotax-owner.com/rotax-forum/4-general-discussion/5087-thermo-bob-coolant-thermostat#9604 Link to comment Share on other sites More sharing options...
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