water temp overheat on 582

[JohnCWE]

Hi guys, I have a problem on my inverted 582 that the water temp goes to 90 deg but the cht and egt remain fine
cht remains around 120 but the water temps climbs continually, within a minute the temp is 80+ at 4500 rpm and continues rising till power is removed completely.
I cannot even climb to circuit height
I have replaced the water antifreeze mix, the feul, taken the water pump apart, inserted a spiral in the suction water hose in case it was sucking flat.

I ran the engine up and checked the temps

engine water temp 81 deg indicated on MGL

With fluke digital thermometer:
water temp entering radiater, 69 deg
water temp leaving radiator, 58 deg
temp of the engine block between the cylinders against the head, 79 deg
temp of hose fitting leaving the block, 69 deg
I have taken the small steam return pipe that goes to the header tank off and blown through it, it is unblocked
I have pumped the radiator hose in an attempt to expell any air that could be in the system.
I removed the steam return pipe from the header tank while the engine was running and water does come out, I did not let this run long though, maybe 2 sec
It seems that the water is circulating around the engine but not around the cylinders, as if the water around the cylinders is stationary.
I have checked the temp probe, 100 deg when the kettle boils
The thermostat is wide open at 80 deg
Any suggestions that I can still look for
What is the correct way to bleed the system, remember it is inverted
Thanks
John

[Sukkelaar]

Morph is your man

regards

[Duck Rogers]

John, please tell me what led up to this situation. Was it always like this? Did you do any work on the engine and now it runs hot or is this a new installation?
Also, blue top or silver top 582?
Also, what pressure is your radiator cap rated at?
Also, is the radiator higher or lower than the engine?
It's important to know in order to diagnose the problem.

[JohnCWE]

Hi Duck, I don't know what brought it on, nothing has been done to it that should lead to this problem.
I flew down to Andrews field about a month ago at 14h00 with no problems whatsoever, got it out of the hanger on Friday morn, got to circuit height and saw the temp was in the red at high 80 deg, throttled back, competed the circuit and landed uneventfully, attempted again, same story.
Drained all the feul and added newly mixed feul just in case it was something to do with the feul being a month old, no improvement.
Took the cowlings off and ran the engine so that I could see if anything was amiss, engine gets to 80 deg in less than a minute.
I then got a fluke thermometer out and started taking temps in different places on the engine
everything is cool other than the barrels, the water temp indicates 81 deg, the temp against the cylinder head between the barrels was at 79 deg, so he MGL is accutate, the water outlet on the head was 69 deg and the water inlet at the pump was 58 deg, one can almost hold the radiator tank immidiately after shutdown while the MGL was indicating 81 and the fluke 79.
here was definitely no correlation betwee the temp ofnthe engine and the temp of the water in the radiator
It is an inverted blue top engine and the engine is above the radiator, actually the radiator is across the center front of the engine, it is mounted up against below the gearbox and is higher than the cylinderhead but lower than the pump, a standard long thin rotax radiator
The water flow out of the cylinder head and into the bottom of the radiator on the cab side and exits at the top on the pump side,
If I look at the diagrams in the manual the flow is wrong but the airplane has 800 hours on like that so it is not wrong.
This problem has cropped up only in the last 1/2 hour.
I removed the thermostat this evening and popped it into some hot water with another one that I have here and they both open at the same time and are wide open at 80 deg.
The thermostat seems to be some sort of 3 way valve that allows the water to circulate through the block while the engine is cold and then diverts it to the radiaor when it warms up.
Does the thermostat have any sort of rubber seat in the block where this divert portion seats, seems like it is metal on metal.
Was wondering if this could be not shutting properly and so allowing water to circulate through the engine without diverting to the radiator.
I want to see if it seats correctly when it is hot tommorrow, as it opens it must backseat and close off the bypass
I dont think this is staying open though as the water temperature measured on the pump spigot under the rubber hose that returns the water from the head is also at 58 degrees, same as the returning radiator water, and would have been at 81 deg if it was bypassing.
when the water temp was at 81 deg the CHT was indicating 92 deg
The EGT is also normal.
On take-off the CHT and EGT rise to the normal rapidly and cool rapidly when power is reduced, but the water temp rises slower and then cools down very slow, it is still around 80 when I was back on the ground after a glide approach and using minimum throttle setting,
Everything seems to point to low water flow but if this were the case the radiator would be boilng hot also.
The radiator cap pressure I do not know but would think it is fine as the water overflows to the resovior and returns to the header when it cools down
As a test I left the engine running at 4500 rpm as the temp was rising and it goes all the way to 100 deg when I throttled back and shut it down, but by then it had pushed enough water back into the bottle to make it overflow, which makes me think that it is an airlock that is allowing steam to form
I hope this gives you some more info
Thanks
John
My cell is 082 457 1171, if you want could you send me an sms and I will phone you back

[Sad-Ham]

Please keep this post going guys as I have a similar problem on my blue top 582.

My temp is constantly around the 80 deg mark during the summer months and around the 70 deg mark during winter. Have also drained, fluushed,changed the temp probe and guage, changed the water to anti-freeze ratio but all to no avail. Would like to know if you come up with a solution that I could also try.

[Tribal Croc]

I am sitting with the same problem on my 582 blue top.

After it came back from the crank replacement my temps is running between 80 – 90.

The one afternoon it went as high as 100 and after landing I found that some of the fluid was pushed out through the cap.

Seeing that the cap didn’t seal I put a little bit of grease on the rubbers and whala no more leaking ,but my temps are still running between 80 - 90

[falconp1]

IMHO This really sounds like a sticky thermostat. If it were me i would run the motor without the thermostat.
If it persists then it has to be something else. The other possibility is a blown head gasket. If the exhaust gas is pushing into the water jacket it will prevent the water circulating around the cylinders. Smell the overflow header tank. If you can smell exhaust fumes then it's the head gasket. Hope i don't confuse the matter further.

[Kalahari]

IMHO This really sounds like a sticky thermostat. If it were me i would run the motor without the thermostat.
If it persists then it has to be something else. The other possibility is a blown head gasket. If the exhaust gas is pushing into the water jacket it will prevent the water circulating around the cylinders. Smell the overflow header tank. If you can smell exhaust fumes then it's the head gasket. Hope i don't confuse the matter further.

I tend to agree with this, I once had the same scenario on a bakkie of mine where the head started to corrode away and gasket started to blow, because the pressure in the combustion chamber is much higher than in the cooling system it forces air into the cooling system that result in less water that come into contact with the sleeves to cool them and the temperature rises and this explains to me why your overflow bottle become full after a while because the higher pressure from the combustion chamber force air into the cooling system which result in the water beeing forced from the cooling system into the overflow bottle. You will notice that the one way valve in the radiator cap do not need a lot of suction to suck the water back into cooling system once the engine cools down (much less that the pressure to force it out into the expansion bottle) therefore if the gasket is not totally blown it will seal good enough for water to be sucked back into the cooling system once it cools down.

I am no fundi on a 582 and I might be wrong.

I am willing to swallow my theory should I be wrong, and for your behalf I hope I am but I have no other logical explanation to this scenario.

Please keep us posted on the outcome

[JvTonder]

I am sitting with the same problem on my 582 blue top.

After it came back from the crank replacement my temps is running between 80 – 90.

The one afternoon it went as high as 100 and after landing I found that some of the fluid was pushed out through the cap.

Seeing that the cap didn’t seal I put a little bit of grease on the rubbers and whala no more leaking ,but my temps are still running between 80 - 90

Hi Tribal croc, het jy al vir Andre gebel om te hoor wat hy sê?

[Morph]

Replace the top resevour with a large bucket full of water. Flow should be bucket to radiator to water pump though engine and back to bucket. Keep the mags off so she doesn't start and use the starter motor/pullstart to crank the motor, check if there is water pumping though and out of the bottom of the engine. This will give you an idea if there is a blockage or not.

[Kalahari]

Replace the top resevour with a large bucket full of water. Flow should be bucket to radiator to water pump though engine and back to bucket. Keep the mags off so she doesn't start and use the starter motor/pullstart to crank the motor, check if there is water pumping though and out of the bottom of the engine. This will give you an idea if there is a blockage or not.

Hi Morph

Am I right if I say that the engine need to be hot for this experiment to allow the thermostat to open in order to allow flow of water through the engine?

[JohnCWE]

further updates.
I drained the engine completely, removed the radiator hose where it goes into the water pump, and efilled the header tank.
When the water came out of the radiator hose to indicate that everything except the block was filled there was till around 2 liters of water left in the bucket, this had to be equal to the volume in the barrels and block, it couldn't fill the block because the thermostat was closed, put the hose back on the pump and added the rest of the water, it took all the rest of the water so assume that the barrels had to be full to start with.
looking in the parts manual I saw there are 2 thermostats for the 582, one that is a 3 way valve for the blue top and a standard one, but the 3 way one is marked "thermostat 55 C degree" so I wondered if it must operate at 55 deg C
I had previously tested it to see if it was open at 80 deg but not 55
Popped it in some 55 deg water and it starts opening, at 60 deg it is wide open

Tomorrow I will blank off the bypass line completely, remove the thermostat, and run the engine up.
I would expect to see that the temps are all equal throughout the system, inlets around 58 to 60 deg and outlet around 10 deg higher maybe.(?)
If this isnt what happens the the only thing left is to remove the engine and strip it down.
I have exlored the suggestions as you guys have suggested but the problem persists stubbornly
The last suggestion that I have comes from Duck Rogers is that maybe one of the O=rings has come adrift around the cylinder barrel and this is bubbling gas into the water and pushing it into the bottle, the lowering water level causes steam to form and so compounds the issue.
According to the manual the pump should pump 2 liters/ sec at 6000 rpm, so at 4000 it should be around 1.2 - 1.5, I would think that sort of flow would carry any gas with it and not give the gas any time to form any sort of airlock in the barrel.

I have been running most of the testing at 4000 rpm because standing behind the prop taking temp readings on an engine running at 6000 rpm is not very lekker, a mite scary, never mind it blowing my perm deurmekaar, not recommended, 4000 is the very top of my comfort zone limit.
I also want to try the bucket idea of Morph's to see if I can measure the actual waterflow and then I should also be able to see if any bubbles are being created.

I removed the waterpump housing and the impellor to look-see, the impellor is about the thickness of the gasket proud of the casing and when I fitted it into the pump housing it is about the same below the casing level, so it is not as if the clearance between the impellor and casing has changed. the flat on the impellor is undamaged,
There are no scuff marks on either one to indicate any scouring or rubbing
The Oil level in the shaft lubricater filler resovior hasn't changed so I don't have reason to suspect anything behind the water seal.
I dont think it has anything to do with the rebuild directly as it has run a trouble free 28 hours since then, it is something that has gone wonky overnight
Till tommorrow,
Thanks
John

[Duck Rogers]

I also want to try the bucket idea of Morph's to see if I can measure the actual waterflow and then I should also be able to see if any bubbles are being created.

Only WITHOUT the thermostat AND with the bypass blocked off.......or with the engine at operating temps and the thermostat fully OPEN..

[Gompou]

Hi Duck
Out of curiousity? Does the water in the bucket have to be hot if the engine is at operating temp. Thinking here of the principal that you cannot
put cold water into the radiator of a vehicle it it isn't idling - danger of cracking the top.

[Duck Rogers]

Good point Gompou.

It will probably have to be hot. Sort of defeats the object of the Bluetop design principle if we now go chucking cold water around a hot cylinder.
Didn't think it through before I posted.. but the idea was to see if the waterpump is working and whether there are any blockages or restrictions in the system. Can't do that if the water is recycling through the head back to the waterpump. And in any event, the thermostat is gonna close up when it "sees" the cold water.
And also, if it's hot water, there's always a chance of someone getting burned

Well spotted mate