Comments - Engine News - Zenith Aircraft Builders and Flyers2024-03-28T08:50:59Zhttps://zenith.aero/profiles/comment/feed?attachedTo=2606393%3ABlogPost%3A259125&xn_auth=noPhil: I'm still not sure abou…tag:zenith.aero,2013-01-10:2606393:Comment:2593632013-01-10T17:00:36.673ZJohn Marzullihttps://zenith.aero/profile/JohnMarzulli
<p>Phil: I'm still not sure about the root cause. There are a few hypothesis's</p>
<p></p>
<ul>
<li>Oil temps were a bit higher to start with, so the coolant may have been expanding and dumping out</li>
<li>Vacuum in the bottle causing the coolant to be pulled out</li>
<li>Large air bubble pushing the coolant out.</li>
</ul>
<p></p>
<p>I'm open to other hypothesis's.</p>
<p>Phil: I'm still not sure about the root cause. There are a few hypothesis's</p>
<p></p>
<ul>
<li>Oil temps were a bit higher to start with, so the coolant may have been expanding and dumping out</li>
<li>Vacuum in the bottle causing the coolant to be pulled out</li>
<li>Large air bubble pushing the coolant out.</li>
</ul>
<p></p>
<p>I'm open to other hypothesis's.</p> just thinking if you havent a…tag:zenith.aero,2013-01-10:2606393:Comment:2593612013-01-10T16:04:21.390ZRaymond Paulhttps://zenith.aero/profile/RaymondPaul
just thinking if you havent already checked, when pistons over heat but dont sieze up they have a tenduncy to shrink in size, gives huge piston rattle when reassembled and running and starts consuming large amounts of engine oil.
just thinking if you havent already checked, when pistons over heat but dont sieze up they have a tenduncy to shrink in size, gives huge piston rattle when reassembled and running and starts consuming large amounts of engine oil. phew what great news John, se…tag:zenith.aero,2013-01-10:2606393:Comment:2592882013-01-10T15:47:56.207ZRaymond Paulhttps://zenith.aero/profile/RaymondPaul
<p>phew what great news John, seems the insurance guys have helped you out some what. Well that goes to prove if you act within the conditions of insurance it pays off, something maybe not all of us a fully aware of when hiccups happen.</p>
<p>Glad the motor is checking out ok thus far, looking forward to the final speculation as to how this happened, as was mentioned rotax's dont just do this sort of hiccup.</p>
<p>phew what great news John, seems the insurance guys have helped you out some what. Well that goes to prove if you act within the conditions of insurance it pays off, something maybe not all of us a fully aware of when hiccups happen.</p>
<p>Glad the motor is checking out ok thus far, looking forward to the final speculation as to how this happened, as was mentioned rotax's dont just do this sort of hiccup.</p> For comparison purposes. My w…tag:zenith.aero,2013-01-10:2606393:Comment:2591852013-01-10T13:04:13.514ZBob McDonaldhttps://zenith.aero/profile/BobMcDonald
<p>For comparison purposes. My winter kit here in Canada consists of about 3 widths of Duct Tape across the bottom of my cowl opening for the oil cooler. I put nothing over the front of the radiator opening. My oil temps run 195 - 212F and cylinder temps 200 - 225F depending if the outside air temps are -20C to +10C. I have a Rotax 912 oil thermostat but never installed it, and it requires 4 connections in the oil lines + the thermostat itself all of which could fail with "Bad Day" results. I…</p>
<p>For comparison purposes. My winter kit here in Canada consists of about 3 widths of Duct Tape across the bottom of my cowl opening for the oil cooler. I put nothing over the front of the radiator opening. My oil temps run 195 - 212F and cylinder temps 200 - 225F depending if the outside air temps are -20C to +10C. I have a Rotax 912 oil thermostat but never installed it, and it requires 4 connections in the oil lines + the thermostat itself all of which could fail with "Bad Day" results. I prefer to idle the 10 - 15 minutes it takes to properly warm my engine (KISS). The other benifit of using EVANS NPT is the long life of the coolant. It was 6 yrs ago I filled my CH601HD Rotax 912A 80 hp (1400 hrs)... I check the level but never give it much more attention than that. The 50/50 anti-freeze mixtures go "sour" and the PH turns toward acid = corrosion issues.</p> John,
Thanks for the update -…tag:zenith.aero,2013-01-10:2606393:Comment:2592712013-01-10T05:10:37.918ZPhil Smithhttps://zenith.aero/profile/PhilSmith
<p>John,</p>
<p>Thanks for the update - still curious to know what you come up with as the, as they all have asked, root cause. The melted bottle has me scratching my head. Seems even if the bottle had a hole that the coolant would have just vented what would have been a small amount that is used as the surge back and forth between hot and cool engine. Do you think that when the bottle failed that there was a negative pressure in that part of the cowl that "sucked" the coolant through the…</p>
<p>John,</p>
<p>Thanks for the update - still curious to know what you come up with as the, as they all have asked, root cause. The melted bottle has me scratching my head. Seems even if the bottle had a hole that the coolant would have just vented what would have been a small amount that is used as the surge back and forth between hot and cool engine. Do you think that when the bottle failed that there was a negative pressure in that part of the cowl that "sucked" the coolant through the overflow circuit?? What pressure cap were you using at the time.</p>
<p>BTW check Jeggs.com for a source of a more substantial bottle</p>
<p>All's well that ends sort of well - have a great year.</p>
<p></p>
<p>Phil</p>
<p></p> John,
Thanks for the update.…tag:zenith.aero,2013-01-10:2606393:Comment:2591402013-01-10T03:06:26.352ZRick Georgehttps://zenith.aero/profile/RickGeorge10
<p>John,</p>
<p>Thanks for the update. I thought long and hard about using Evans, but decided against it due to the comparatively poor heat transfer rates. Since I also have a 912; I would sure like to understand the root cause of your lose of coolant. </p>
<p>John,</p>
<p>Thanks for the update. I thought long and hard about using Evans, but decided against it due to the comparatively poor heat transfer rates. Since I also have a 912; I would sure like to understand the root cause of your lose of coolant. </p> Actually I am now rethinking…tag:zenith.aero,2013-01-10:2606393:Comment:2591722013-01-10T01:43:55.288ZJohn Marzullihttps://zenith.aero/profile/JohnMarzulli
<p>Actually I am now rethinking Evans NPG with the "New Style" 701 Cowling:</p>
<p><a href="http://www.rotax-owner.com/rotax-blog/item/13-on-the-fence-about-coolant" target="_blank">http://www.rotax-owner.com/rotax-blog/item/13-on-the-fence-about-coolant</a></p>
<p>Actually I am now rethinking Evans NPG with the "New Style" 701 Cowling:</p>
<p><a href="http://www.rotax-owner.com/rotax-blog/item/13-on-the-fence-about-coolant" target="_blank">http://www.rotax-owner.com/rotax-blog/item/13-on-the-fence-about-coolant</a></p> I'm still not sure why the bl…tag:zenith.aero,2013-01-10:2606393:Comment:2590432013-01-10T01:11:04.303ZJohn Marzullihttps://zenith.aero/profile/JohnMarzulli
<p>I'm still not sure why the blow out of coolant occurred. The oil cooler and radiator had some aluminum tape on them to keep the engine warm, otherwise I would not be able to get to 120F.</p>
<p></p>
<p>During the flight the oil temps were warmer than normal, but withing bounds. My theory is that maybe as the engine warmed up, the DexCool expanded, blowing out the overflow line. As more coolant blew out the engine got hotter causing more coolant to blow out...</p>
<p></p>
<p>There was about a…</p>
<p>I'm still not sure why the blow out of coolant occurred. The oil cooler and radiator had some aluminum tape on them to keep the engine warm, otherwise I would not be able to get to 120F.</p>
<p></p>
<p>During the flight the oil temps were warmer than normal, but withing bounds. My theory is that maybe as the engine warmed up, the DexCool expanded, blowing out the overflow line. As more coolant blew out the engine got hotter causing more coolant to blow out...</p>
<p></p>
<p>There was about a half pint left in the engine.</p>
<p></p>
<p>My plan is to switch to NPG and a zero-pressure cap. I also plan on changing the bottle to be something other than the stock part, and hopefully not plastic.</p> What was the root cause of th…tag:zenith.aero,2013-01-10:2606393:Comment:2592522013-01-10T01:00:56.828ZBob McDonaldhttps://zenith.aero/profile/BobMcDonald
<p>What was the root cause of the over heat condition? Water pump failure, a bad coolant tank rad cap... what caused the over heat condition? Rotax 912's don't normally "blow" the coolant out of the engine, over heated they will as would any engine. It is good to hear your damage is limited, and the engine can be repaired. Using EVANS NPT waterless coolant with a zero pressure coolant tank rad cap is approved by ROTAX in this engine and you will never "blow" the EVANS into the coolant…</p>
<p>What was the root cause of the over heat condition? Water pump failure, a bad coolant tank rad cap... what caused the over heat condition? Rotax 912's don't normally "blow" the coolant out of the engine, over heated they will as would any engine. It is good to hear your damage is limited, and the engine can be repaired. Using EVANS NPT waterless coolant with a zero pressure coolant tank rad cap is approved by ROTAX in this engine and you will never "blow" the EVANS into the coolant tank.. You have a good insurance agent / company perhaps you can offer their name as a recommendation to other pilots.</p> John
I'm glad to hear that th…tag:zenith.aero,2013-01-09:2606393:Comment:2592502013-01-09T23:39:43.914ZJoe Byrdhttps://zenith.aero/profile/JoeByrd
<p>John</p>
<p>I'm glad to hear that there was no more damage than that to your engine. Good luck and I hope you are back in the air soon.</p>
<p>John</p>
<p>I'm glad to hear that there was no more damage than that to your engine. Good luck and I hope you are back in the air soon.</p>