Slow Glycol Loss - 582 Rotax Kitfox III

15 posts in this topic

Posted

Have a frustrating one here. I lose about 1/4 height of my overflow bottle (which looks like a large pill bottle for a Kitfox), over about 10 hours of flying.   Is any loss typical?

Seems to only be a small loss under pressure somewhere.  No external leaks that are apparent.  RV oil level is holding constant with no evidence of contamination. Looking up the exhaust into the cylinders and head/cylinder junction area show no evidence of leakage or even a static drop (though the engine is cold by then).  Next plan is to do a 10 psi hydrotest with internal cylinder inspection at that time.

Anyone run across this before?

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Posted

Rad cap top seal getting weak? Replace the cap.

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Posted

You can do a leak check of the coolant system.  Most auto parts stores these days will rent you tools if you don't want to buy one.  I pressured mine to 14 PSI and it held... but it still had a bad head gasket that leaked at higher pressures.  Are you getting any discoloration in the coolant bottle?  Triple check all hose connections.  Do you have a weep hole on the water pump shaft cover, block, what ever you want to call it that the RV shaft runs through?  Any evidence of leakage or weeping there?

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Posted

You can do a leak check of the coolant system.  Most auto parts stores these days will rent you tools if you don't want to buy one.  I pressured mine to 14 PSI and it held... but it still had a bad head gasket that leaked at higher pressures.  Are you getting any discoloration in the coolant bottle?  Triple check all hose connections.  Do you have a weep hole on the water pump shaft cover, block, what ever you want to call it that the RV shaft runs through?  Any evidence of leakage or weeping there?

Actually no discoloration in the coolant bottle at all (still looks like new coolant in the bottle and under the cap when I take it off).  All connections dry as can be (yep, have been over them at least 3 times, o.k. maybe 5 times).  The weep hole I am not familiar with however.  Not sure if I have one or not. If I do, I assume it is on water side of the shaft vice the RV side?   I have no drips anywhere on the engine (oil or coolant).  I have a 13 psi cap, so I guess the only regions of higher pressure would be whatever head the pump creates.  Hopefully it will make itself evident. 

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Posted

Leni is right, check/replace your rad cap.  I was loosing coolant and the temp was 190ish, it was coming out from the cap. Replaced=prolemo solved!

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Posted

Same thing happened to me.

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Posted

I will give that a quick go (cap change).  Easy one to implement.

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Posted (edited)

What is an acceptable amount of coolant loss (if any) or what is coolant loss indicative of?  I'm having to add coolant to my overflow bottle (goes empty) every 6-8 hrs. I don't see any apparent contamination in the coolant, and the cap does not appear to be leaking.

Edited by allonsye

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Posted

I don’t know what is acceptable. I would be fine with what your doing on my set up. If it was to the point of refilling every hr, then I’d be real curious. FWIW, a buddy had one of the nicest P-51’s around. Money was no object for him. He had a personal mechanic to work on it. It had a new engine, new radiators, new hoses, new everything. They couldn’t get the thing to quit leaking. The old joke was the only way you can get one to quit leaking is to run it out of fluids, that being oil and coolant! Good luck, Bryce

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Posted

EA 6 Prowler Plane Captains (Navy Crew chiefs), say the airplane must be broke if it's not leaking.

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Posted

Radiator cap

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Posted

Rad cap checks good. no visable coolant on externals/engine bay/firewall.  In my case i suspect a slight internal consumption. 70 SMOH.  Is that normal? Who knows.

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Posted

Is this coolant loss a continuous thing over many many hours of operation or have you just noticed after getting your bird up in the air?

I try to really think through coolant flow, where the high spots in the system are and is there a way for trapped air to exit the system. I try and design for no trapped air. Even with the best planning, my coolant systems (both 582 and 912) always took (take) a few outings after draining and re-filling for the coolant level to stabilize. I will remove the cap following a flight, it will be a bit low, I put a little coolant in, and repeat over several flights. After while all the little air pockets must eventually fill with coolant and it quits taking coolant.

Could it be this is what is happening in your situation?

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Posted

Looks like I kinda hijacked the thread.  Anyways, in my case, there's 70 SMOH and it's been a something I noticed in the last 25 hrs.  And like you Chris, I built with keeping air pockets out in mind.  I'm getting the distinct impression that coolant is being consumed through the combustion chamber.  Maybe that's to be expected. I've not found anything to validate either way.

Paul

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Posted

Having same problem with mine now that summer temps are up. So, if the cap is leaking, the fluid will by pass the cap. The only way that you will notice, is the flu I d level in the overflow bottle will go down. It seems that if the cap won't maintain pressure, the operating temps will also go up. Anyways after reading this thread, I ordered a new radiator cap. Lots of good info on this forum

 

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