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582 high engine temp

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4 years 11 months ago - 4 years 11 months ago #4813 by Michael Regan
Michael Regan created the topic: 582 high engine temp
Hi all,

Have been having problems with my Rotax 582 for a month now. I am somewhat over the main fuel problems now after doing a rebuild of both carbies and replacing all fuel filters and flushing the lines, and replacing all fuel with fresh. The only thing I haven't done so far is the fuel pump, but before I pull this apart, I seek any help/ideas on what might be causing the following.

I took off in 85 deg OAT last evening and even before I climbed to 1000 feet the engine temp was 185 deg with the EGT's both within range. The left one 1100 and the right 1150. I tried to cool it down at low rpm but could not, so returned to land. The water levels were checked prior to flight.

Any advice welcomed.

Mike
Last Edit: 4 years 11 months ago by Michael Regan. Reason: Link no good

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4 years 11 months ago #4828 by bill martin
bill martin replied the topic: 582 high engine temp
Mike,

If the EGTs are normal, it's not a fuel problem. If your 582 is a bluehead, it could be a bad thermostat. You can heat the thermostat in a pot of water on the stove with a meat thermometer and see if it begins to open at the right temperature.

Bill.
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4 years 11 months ago #4831 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
Never thought of that... thanks bill. I am wondering now if I should try operating without the thermostat at all? Thats what we used to do to the old Ford years ago. I understand that this would of course take longer at warm up, but think the sacrifice might be worth it. Anyway I will try bills idea first, and if it proves it is working properly, I will leave it out, and if it shows faulty, I will replace it. As a matter of interest bill (or others) what would be your normal operating temp at OAT 85deg?


mike

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4 years 11 months ago #4833 by George Gennuso
George Gennuso replied the topic: 582 high engine temp
I just installed a new 582 Blue head in my airplane. I was running very high engine temps (185+ F.)and I tried everything to get it to run cooler. I did all of the checks for traped air bubble, checked the thermostate and replaced the radiator cap. Flushed the radiators. Nothing seemed to help until I read on the internet about the anti freeze mixture. I was running the recomended 50/50 mix in the engine. What you overlook is that the anti freeze is there to prevent the water from freezing not cooling the engine. I reduced the mixture to a 10% antifreeze and 90% water and that brought the cooling way down. It now runs at 150 to 160 F. If you don't have to worrie about your water freezing you might give it a try.
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4 years 11 months ago #4834 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
George... very interesting. Where I live it never ever gets below freezing temp, so maybe I will try that too. I suppose I should empty and refill again, but I dread the time taken getting all the air locks out. Wish there was a way to stop this happening every time. I wonder if I just "trickle" the water in and see if that works. I do wonder though why rotax recommends 50/50. Will report back when I have the work done and the next flight completed. This could be a week or so though.

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4 years 11 months ago #4835 by Nick Axworthy
Nick Axworthy replied the topic: 582 high engine temp
Not sure I would like to run an alloy engine on such a weak anti freeze mix....

Dont forget one of its main jobs is to keep corrosion at bay...as well as being a coolant,

I no expert on Rotax coolants but I would have thought its main job is just to transport unwanted heat to the rads and for them to dissipate the heat....and I think to Rotax spec type raises the boiling point,

Running an engine to cool is a prob as well....as others have said and if it where me I would check out your thermostat....I take it the engine did used to run at normal temps....has the airflow to the rads been altered in anyway.

Nick.

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4 years 11 months ago #4843 by bill martin
bill martin replied the topic: 582 high engine temp
Mike,

My operating temps were around 170f at WOT and 150 at cruise and I had to use adjustable louvers to keep the cruise temps up around 150f in the winter.

You may get into a strange situation with no thermostat in the engine. The 582 thermostat acts as a two way valve which forces coolant through the bypass when the thermostat is closed and through the radiator when the thermostat is open. With no thermostat in the engine, the coolant can go through the bypass and the radiator at the same time.

I have never tried to run a 582 without a thermostat so I can't say how the temps would react. It wouldn't hurt to try if you keep a close eye on the temps. Just a guess, but if the thermostat is bad and permanently closed, removing it could only help. How much I couldn't say and there would be no temperature regulation.

I have always run a 50/50 mix of silicate free Dexcool antifreeze.

Another thing you might check is to pull the pump housing off the block and see if the impeller is OK and tight and no debris inside.

Bill.

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4 years 11 months ago #4844 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
Nick, although I tend to agree, I still might consider less anti-freeze...say 40/60. Nobody knows the Rotax engine better than Rotax, so I guess it's best not to wander too far from their recommendations. As far as I know there is nothing new in the airflow.

mike

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4 years 11 months ago #4845 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
Wow bill, thanks for your temps. I realize now this engine has always over heated and its only because this is the first time I have flown in the higher OAT range that has caused it to over heat. Even in the winter it would reach 180 with WOT if I climbed more than 1000 ft at a time, and cruise aprox 165-170. Time to doto the same to the cooling system as I did with the fuel system.

Thanks to all for helpful comments.

mike

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4 years 11 months ago #4859 by Ian Jones
Ian Jones replied the topic: 582 high engine temp
I have had this problem, and checked everything including the thermostat and water temp sensor.

My problem was the capacity of the radiators - I used the 2 part radiator system. You will find that the blue head 582 requires larger size radiator cores. Check the CPS catologue which will show the different configurations. When I fitted a new blue head 582 in place of the older grey head 582, I did not change to the larger radiators. This resulted in overheating every time I flew, and was becoming a serious problem to manage the water temperature. Once I realised what the issue was, I fitted a third radiator panel - problem solved.

So my advice - investigate the ability of your radiator(s) to provide sufficient cooling capacity.

Pud.
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4 years 11 months ago #4860 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
Hey Pud, actually I apologize for not adding earlier that I have the old grey head and it does have the 2 part radiator system. I still wonder though if I can add a mod to increase capacity like yours? Last evening I took it out again after withdrawing one liter of coolant and adding one liter of distilled water. Although it still reached 185 degrees in a climb to 1500' it did however cruise after it settled down at about 165 degree which is a bit better than before. I say "about" because I can only guess, so I made a picture of the same gauge as my Mitchell temp gauge (below) to ask you guys what temps do you think are position 1 and 2 (in case the pic dont look too good, that is the two dashes between 100 and 180). I was assuming it was pos 2 = 140 and 3 = 170.

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4 years 11 months ago #4861 by Ian Jones
Ian Jones replied the topic: 582 high engine temp
G'day Michael,
I live in Western Australia where the temps get somewhat hot during Summer. My temp gauge is in degrees Celsius, and the Rotax engine manual specifies maximum temp of 80 degrees C. This converts to approx 180 degrees Farenheit. My gauge is similarly set up as yours with the intermediate marks not being equidistant. I just monitor the gauge very closely and manage the engine revs when temp readings go past the last mark before 80* . Since the radiator modification I have only seen the gauge get above 70* once, and never to 80*.

Check out the attached photos for my set up.

The last photo is off topic but adds interest ;)

The nose art is based on a photo of my wife taken when she was about 20, som 30 odd years ago.

Hope you solve your problem soon Michael.

Pud

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4 years 11 months ago #4862 by bill martin
bill martin replied the topic: 582 high engine temp
Mike,

Didn't realize you had a grey head mod. 90. Since the grey head didn't have a coolant bypass system you can certainly take the thermostat completely out with no problems other than a longer warmup. It wouldn't hurt to try it temporarily. I wouldn't recommend it on a permanent basis. You can get into a new set of problems if the engine runs too cold.

Bill.
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4 years 11 months ago #4863 by Brian Van
Brian Van replied the topic: 582 high engine temp
I read above where checking the thermostat is discussed, which is a great idea.

But I didn't see mention of calibrating the gauge. I don't have a procedure but one must exist?
I think it is bad idea to assume the gauge/sensor is accurate.
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4 years 11 months ago #4864 by Ian Jones
Ian Jones replied the topic: 582 high engine temp
That's why, in my case Brian, I checked the temp sender - the one that screws into the head. I unscrewed it from the head and placed it in a pot of very hot water, then monitored the water temp guage on the instrument panel against a separate temp gauge I had. Both read within a few degrees of on another as far as I could tell.

I also did a similar thing with the thermostat where I placed it in a pot of cold water over the stove and heated it up. I monitored the thermostat opening and took a temp reading from my thermometer which was placed in the water. I forget now - have it written down somewhere, at what temp the thermostat starts openiing at, but it was right on the money. So I eliminated 2 possibilities within a short space of time at no cost.

Pud
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4 years 11 months ago #4865 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
Thanks all for all your input on this...all good points.

Done some more work on it tonight. Man am I a dummy I tell ya. I thought I was removing the thermostat housing but instead I was removing the water pump cover. They both look a bit the same when checking the manual. I am currently stopped halfway while I wait on a water pump gasket delivery, but I can tell you what I found out so far...

1/ There doesn't seem to be a thermostat anywhere that I can find. The other side of the engine has a smaller water connection to the block that looks like no thermostat could possibly be inside. Where is it normally situated???

2/ I completely drained out all the old coolant into a measured container and all that was there is 3.2 liters(about 7 pints I think). Thats weird because there is supposed to be about 4.2 liters...so 1 liter is unaccounted for because it always showed full under the cap. Maybe some kind of airlock?

3/ When I removed the water pump cover I could then see clearly the impeller inside... it appears to me the impeller turns the wrong way when turning the prop in the right direction. I could be wrong.... what do ya'll think? See below attachment

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4 years 11 months ago #4866 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
I can now answer question one at least... the thermostat is in fact behind the small water connection on the other side. Thanks google images

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4 years 11 months ago #4869 by bill martin
bill martin replied the topic: 582 high engine temp
Mike,

Your pump is turning in the right direction. It pulls the coolant from the hose into the center of the impeller and forces it outward and into into the block through the two holes on each side of the impeller. The small hole in the impeller is to allow cavitation bubbles to escape.

The thermostat is normally located right where you found it. If you have to replace the thermostat, be sure you get the one for the model 90 greyhead. The model 99 bluehead thermostat is designed entirely differently.

Depending on how your cooling system is mounted, it is sometimes difficult to drain all the fluid out. Especially in the crossover hose under the twin radiators. Not likely to be any air in there though. One thing you might check is the steam vent with the small hose attached which goes from the cylinder head to the radiator. ( I can't remember if the greyhead has one or not) If this is blocked, it can allow air and steam to be trapped in the top of the head right where you need coolant the most.

Bill.
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4 years 11 months ago #4876 by Michael Regan
Michael Regan replied the topic: 582 high engine temp
Well thats a relief... thanks Bill. Now I can discount the pump altogether at least.

Today I pulled out the thermostat and put it into 65 degree hot water and it opened just nicely, so I can also discount the thermostat. Next flushed the engine with plain water, and refilled it with plain water as well. No mater how slow I poured the water, and no matter how high or low I put the tail (to get level), I could not get more than 2-1/2 liters of water into the engine. I then ran it at 4000 rpm for 5 minutes to try and clear any air locks so I could get the 4 liters the specs say, and she reached 170-5 degrees, but the main thing to note is the air lock did not clear and the water level stayed the same.

Back to the drawing board. Waited for the engine to cool down, then disconnected the radiator hose and hooked up the garden hose and flushed the whole engine both ways and noticed no discolor in the water at all. It all looks good, so put it all back together but before I put the thermostat back I drilled a couple of 1/8" holes in it to hopefully help the coolant seep through better so I might refill the full 4 liters this time. Its too dark now to do anymore now so will finish tomorrow and test fly and see what happens.

I didn't see and steam vent from the head, but did see what might be the steam vent coming off the top of the water pump and going back to the radiator cap. See the pic below and some others as well just to give you an idea of my setup.

Mike

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4 years 11 months ago #4885 by bill martin
bill martin replied the topic: 582 high engine temp
Mike,

Didn't realize the engine was inverted. For an inverted engine, the water pump is the proper location for the steam vent. It sounds like you have checked everything. Could it be that your temp gauge or probe is reading wrong? Easiest way to check is to remove the probe from the block, leave it hooked to the sending wire and attach a temporary grounding wire to the probe. Now dip the wet end of the probe into a cup of very hot water with a thermometer and see if the gauge and thermometer match.

You might get lucky and find you don't even have an overheating problem.

Bill.
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