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  #1  
Old 02-09-2016, 08:17 AM
tadpole rider tadpole rider is offline
 
Join Date: Oct 2010
Location: Independence, OR
Posts: 56
Default High CHT warning

This is in a new -12 with first flight last Saturday. We did not fly too long as the CHT went into the yellow. We tried the climb to 10,000 but as we passed 1,500 the CHT went in to the red and it cooled down as we returned to the airport.
OAT low 60'sF.
Rotax 912 with the newer CHT probes that actually measure coolant temps.
Zerex Dex-Cool 50/50 coolant.
Cooling system has been purged of air and topped off.
The CHT sensors have been checked against boiling water and the give the correct resistance and the reading on the Skyview matches.
On the climb-out at 75 KIAS the temperature peaked at 270 when we aborted the climb. The oil temps were in the green.
The radiator was pulled and back flushed.

Any other suggestions? Van's had none.

N4212C
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  #2  
Old 02-09-2016, 08:34 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
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Even though the cooling system has been purged of air, check it again to be sure.
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RV-12 Flying
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  #3  
Old 02-09-2016, 08:35 AM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,587
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CHT's match, both sides hot?
Fluid level still normal after landing?
Factory built or kit built?
Air duct unobstructed?
Hoses properly routed and unobstructed?
CHT normal on ground runs?
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John Peck, CFII, A&P, EAA Tech Counselor, Flight Advisor.
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RV-12 N37JP 120176 Flying since 2012.
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  #4  
Old 02-09-2016, 08:57 AM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Post a photo of the cooling air inlet on your cowl.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #5  
Old 02-09-2016, 09:06 AM
tadpole rider tadpole rider is offline
 
Join Date: Oct 2010
Location: Independence, OR
Posts: 56
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CHT's match, both sides hot?
Right side ran 5 - 7F higher than left.
Fluid level still normal after landing?
Fluids topped off after first flight but o.k. on 2nd and 3rd flights.
Factory built or kit built?
Kit built E-LSA
Air duct unobstructed?
Air ducts clear.
Hoses properly routed and unobstructed?
Hoses look good but will double check for crimping where they are routed through the engine mount.
CHT normal on ground runs?
Mid/upper green on the Skyview.

I am thinking coolant flow problem. Either an obstruction or a bad impeller in the pump.

After the first flight I could grab the upper hose into the radiator. It was very warm, but not hot enough to burn. The lower hose was comfortable to the touch.
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  #6  
Old 02-09-2016, 10:41 AM
tadpole rider tadpole rider is offline
 
Join Date: Oct 2010
Location: Independence, OR
Posts: 56
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Here are a couple of shots.let me know if you need other images.

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  #7  
Old 02-09-2016, 10:50 AM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by tadpole rider View Post
Here are a couple of shots.let me know if you need other images.

Ok.
Cowl looks good. I imagine you have confirmed that teh duct seals well to teh radiator.

Next thing I would check is for some type of blockage (as you mentioned).
Confirm that none of the shipping plugs were accidentally left in the radiator nipples or the water pump or expansion tank on the engine.
This might be a long shot because it should also cause a rather rapid heat up of CHT's just idling on the ground, but it needs to be ruled out.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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