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Anyone With Niagra 20003A Oil Cooler Cracking Issue?

Steve Pierce

Steve Pierce

BENEFACTOR
Graham, TX
Have a Super Cub with a balanced LyCon 160 O-320 that has cracked two Niagra 20003A oil coolers in the last 400 hours. The airplane has a Sutton exhaust with the rear oil cooler mounting. The crack is adjacent to the bottom oil line fitting where the first two baffles solder together. Talked to Niagra Air Parts and they say there is no epidemic and it is probably strain on the fitting from the hose. The hose is pretty flexible with no obvious bind on it. Just curious if anyone else has had an issue?
 
Maybe a harmonic resonance on the hose? Perhaps altering the hose support arrangement could help to dampen hose vibrations and/or change the natural frequency?
 
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Steve, I have a Niagara 20003A cooler, Ser # G03-1902-107 purchased about 2004; so far 270 hrs without a crack. Mine though is plumbed a little differently. It works fine plumbed this way.
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Steve is that the same place mine was (is still) leaking where the bottom hose is screwed in?
 
Could be now that you mention it. I isolated it by butting a rag under it and wrapping safety wire from the oil cooler mounting bolt to the oil line fitting. No oil in the cowl and the rag was oily inside.
 
Steve Pierce said:
Could be now that you mention it. I isolated it by butting a rag under it and wrapping safety wire from the oil cooler mounting bolt to the oil line fitting. No oil in the cowl and the rag was oily inside.
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I have had similar problem x2 (rear mount cooler, 160HP, with casper labs oil filter). Is your crack at the top of the oil cooler adjacent to where the inlet hose attaches? Both of mine in this same area (see pic). The second one lasted about 100hrs with the first much less. I am thinking that there must be some harmonic induced vibration also. I took special pains to not have any torque in the hose and with the last one attached hose to bottom right mounting bolt middle spacer with a HD zip tie. I am thinking a more rigid mount there like a hose clamp may eliminate any resonance from carrying through to the upper fitting. Did you ever resolve issue?

TP2
 

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Steve, Is it possible the hose fitting was secured into the cooler without using a back up wrench on the fitting boss? Jim
 
Interesting thread... We use Niagara coolers with our oil cooler STC for small continentals.... Never have had a Niagara cooler fail....but, I do know of at least three Aero Classic coolers split open on the cooling fins...

Brian
 
TP2, In my case Steve will be doing a annual on mine next week so he should be able to tell you more then.
 
cruiser said:
Steve, Is it possible the hose fitting was secured into the cooler without using a back up wrench on the fitting boss? Jim
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That was my initial thinking but having seen 2 coolers crack on the same airplane I am not sure. Both cracks were in the first baffle on the bottom adjacent of the fitting. It is a pain to install a back up, takes a crows foot and long extension but doable. With the rear mounted cooler the hoses are short thus less flex in the hose to lessen the effects of vibration.
 
Torque on fitting and won't stand behind 2 yr product warranty. A backup was used and no torque applied past fitting boss. I have aero classics installed now and hoping for better results.
TP2
 
I just reread the thread and it occurred to me that I have seen some cracking on various Lycoming Engines because tubes were not installed around bolts between flanges. Is everyone using tubes to spread the load out to the outer flange? Hanging the cooler just off the flange up against the baffle has caused several coolers to crack around here.
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Good thinking. Not only shares the load, but changes the natural frequency of vibration, in case resonance is part of the problem.
 
Yes, spacers installed. My application includes Cubcrafters rear baffle modification kit, three additional supports, and the 4 aluminum tubes/spacers on mounting bolts.
TP2
 
If your going to Pacific Oil Cooler for repair be aware that they really hook it to you on shipping and handling. Hiding in their shipping charges is a 15.00 handling fee.
 
dougsappllc said:
If your going to Pacific Oil Cooler for repair be aware that they really hook it to you on shipping and handling. Hiding in their shipping charges is a 15.00 handling fee.
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My dealings with Pacific Oil Company went sideways a few years back. I now go elsewhere for my coolers.
 
I have the 9 vane on an RV baffle, with the tube spacers. No cracks in almost 300hrs so far.
 
We had a crack in the mount (CC 180 Cub), but it was due to the baffling flexing. Three bolts, each with spacers, and the top failed. Cooler is OK, but the mount is not good. Folks here suggested steel in the vertical baffle. Great idea.

My Decathlon has the same setup, but no problems. I will take a closer look next time I am in there.
 
Have a cub that’s eaten two aero classics 9 row coolers now with about 10 hours each. Both cracked adjacent to the boss where the top fitting comes in. Anyone had this lately? Thought the first was a fluke, but the second I personally installed and backed up fittings carefully, etc.
 
I have the same oil cooler, rear mounted on an o-375.Have no spacers and have 500 hours since new.Touch wood no cracks (as yet!)Maybe being more flexible it smooths out the resonance?
Troutpeak2 said:
Yes, spacers installed. My application includes Cubcrafters rear baffle modification kit, three additional supports, and the 4 aluminum tubes/spacers on mounting bolts.
TP2
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ak49flyer said:
Have a cub that’s eaten two aero classics 9 row coolers now with about 10 hours each. Both cracked adjacent to the boss where the top fitting comes in. Anyone had this lately? Thought the first was a fluke, but the second I personally installed and backed up fittings carefully, etc.
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How long is the flexible hose which connects the cooler to the engine? If it's too short and the fitting has some side load on it when you attach it, it can crack the cooler.
 
ak49flyer said:
Have a cub that’s eaten two aero classics 9 row coolers now with about 10 hours each. Both cracked adjacent to the boss where the top fitting comes in. Anyone had this lately? Thought the first was a fluke, but the second I personally installed and backed up fittings carefully, etc.
Click to expand...
I had two coolers fail adjacent to the top boss (see pic from 2014) within 10hrs after following all the recommendations religiously. Since securing the hose about 6” from the attach point from flex (both upper and lower hoses), have put several hundreds of hours and 8 years without a problem. I believe the unrestrained hoses had a resonance vibration set up that cracked the coolers prematurely.
 
I just saw this thread. A gent from South Africa landed today in Bozeman due to thunderstorms on his route toward Sheridan. He’s moving the plane from Seattle to Virginia.

To the point: After landing, the damper parking him pointed out a lot of oil on the right side of the plane. There was. Oil level was two quarts remaining. It’s an RV, with rear mounted cooler, on baffle. Arlin of Arlin’s Air determined the leak was coming from the oil cooler, which was cracked. Arlin replaced the cooler and sent him on his way.

The pilot said this was the second cracked oil cooler on that plane in six months. Plane has a total of 95 hours. Scary.

Tomorrow, I’ll find out what brand cooler, and what replaced it. Arlin said he couldn’t see anything wrong with the installation, and Arlin’s seen a LOT of oil coolers.

In any case, I told the pilot he should buy a lottery ticket. He wouldn’t have got much further before that engine was toast.

MTV
 
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