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Coolant hoses

P51krause

Member
We are at the 5 year mark to do the coolant hoses. Can anyone lead us on the best place to get the hoses/hose kit? Trying to find a part number for them through old invoices and can’t seem to find them. Thanks for any help.
Michael Krause
 
Coolant Hoses

McMaster Carr
5 Feet Hi-Temp Silicone Coolant Hose Yarn Reinforced 5/8" ID, 1" OD 5296K321
1 Foot Hi-Temp Silicone Coolant Hose Wire Reinforced 5/8" ID, 1" OD Part#: 5591K12 for 90 degree bend
4 each Constant-Tension Clamp for 1 inch I.D. rubber coolant hose Part #: 54205K17
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NAPA 1" I.D. Rubber Heater Hose Part #: NBH H151
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The original hose clamps are too small for silicone hose. I purchased GRAINGER Hose Clamp, Dia 27mm X 1.6mm, two Pk10 Item # 2UTG8 for 5/8 I.D. silicone hose. I had to cut a little off from the clamp stop-tab to get these clamps open enough to fit over the hose. I would have purchased larger clamps but could not find any 28 or 29 mm clamps. Be careful, some vendors give the hose size, not the clamp size. And the hose gets bigger after being slid onto the fitting.
 
For some reason the link by jrtens didn't seem to work for me. Not sure if he was pointing to the same place but take a look at: https://vansairforce.net/community/showthread.php?t=186607&highlight=hps+hoses.

I used HPS silicon hoses last year and love them. You can reuse the small hose clamps (though I bought a few extra just in case) but be careful to use the correct hose clamps for the radiator hoses. I used the same Constant Tension clamps for these as Mich48041.

HPS Part numbers were as follows (I had plenty left over):
HTHH‐062‐BLUEx10 HTHH‐062 | Blue | 10 Feet
HTHH‐100‐REDx10 HTHH‐100 | Red | 10 Feet
You will also need some 1/4" hose. I used HPS but can't find the details.

For the 90 degree bend, I used the Continental GY58UBP E-Z Coil purchased on Amazon to prevent hose collapse. Very effective.

All this is discussed in depth in the above link. Good luck!
 
I pulled my coolant hoses two days ago (2nd 5-year replacement). I used automotive rubber heater hoses last time, and I would not again. I was surprised to find the hose walls had softened considerably. On the upside it made removal very easy, but it led me to conclude the 5 year replacement with rubber hoses is an imperative. I plan on using silicone hoses this time.
 
Don't buy the hoses that I did (post #4 above). They are 1/8 inch larger in outside diameter compared to the original hoses.
 
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Thank you all. I got the coolant hoses at Lockwood and the radiator heater hoses at NAPA. On the number 4 cylinder bottom coolant hose I had to cut it to get it off, scored the aluminum a bit cutting it at the water pump. So mad. I put some gasket sealant on it and hope it doesn’t leak. (Shouldn’t with how stiff those clamps are) Anyone else have any suggestions besides replacing the whole water pump? Guess I’ll have to wait till I start it up and run it. Thanks again
 
Mike,

I wouldn’t obsess about a surface scratch unless you really gouged it. The coolant system cap is rated for 1.2 bar (about 18 psig) so it’s a pretty low pressure system. I scratched mine too during the first replacement 5 years ago with no resulting problems. The clamp keeps the tube in compression, and axial cracks don’t shear tubes like circumferential cracks do.

One last fact that is interesting, but I wouldn’t rely on: some surface scratches actually put the surface in compression making propagation much less likely. I learned that tidbit while on a root cause of failure team investigating a steam generator tube rupture at the nuke plant where I worked. I always used to say you only really get to know a piece of equipment when it breaks!

Rich
 
Ok one more question. Top number three cylinder coolant hose. What’s the trick, besides removing the fiberglass shroud and or intake manifold. My hose clamp plier flex tool just won’t get a grab on the clamp. Almost like the clamp just needs a slightly deeper flange to catch the lower clamp. Also if it was rounded a bit to mold around the hose a bit. I’ve tried every which way to get in there but to no avail yet. I’ll keep working the problem, but is there a better plier that I can get in there. (The clamp is mostly vertical, so not hard to get to, it just won’t bite into the clamp with my plier flex tool.) Thanks again all
 
Are you using cable hose clamp pliers similar to these? They sure helped me with my installation.
 

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Are you using cable hose clamp pliers similar to these? They sure helped me with my installation.
Yep those are the ones I’m using. It’s just not grabbing that clamp cause it needs bigger “teeth” to grab. I really really don’t like the idea of pulling the intake manifold or the fiberglass shroud. Guess I should have started with this one cause it by far has taken the longest to get at.
 
I’m doing the hose replacement now. You have to lift the intake manifold each annual to get an Allen wrench on the engine mounting bolts to check torque. That makes it much easier. It’s a lot simpler than it sounds.
 
Remove the intake manifold. Use a good fitting allen wrench and maybe order a spare set of attach bolts just in case you round out the head.
 
Remove the intake manifold. Use a good fitting allen wrench and maybe order a spare set of attach bolts just in case you round out the head.

The bolts won't get damaged if you use high quality wrench. You should replace O-ring seals each time manifold is removed...
 
Jim,

I asked the question about the O-rings at the ROTAX course, and the instructor said he just examines them with a magnifying glass for scratches and flattening. If they look OK he reuses them. I’ve been using the same O-rings for 10 years with no issues. I do keep spares just in case.

Rich
 
R398-20744 O-ring Intake to Head 230-910
If you feel the need to use new ones and save some money, these are the ones I use;

Mcmaster-Carr 9263K656
Chemical-Resistant Viton® Fluoroelastomer O-Ring
2 mm Wide, 34 mm ID, 38 mm OD
(10) for $15.00
 
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Just finished my coolant hose 5-year change out with silicone hoses. The thicker wall of the silicone hoses makes them tough to use because clearance is tight with the shroud on top of the engine.

Because I am at the 10-year point I also changed out the oil hoses with the Teflon hoses from Aircraft Specialty. I elected to go with the banjo bolt return line as opposed to the elbow fitting to increase clearance with the muffler. I would not recommend that choice. The clearance increase is minimal and it creates interference with the water pump so I had to reroute the oil return line.
 
Because I am at the 10-year point I also changed out the oil hoses with the Teflon hoses from Aircraft Specialty. I elected to go with the banjo bolt return line as opposed to the elbow fitting to increase clearance with the muffler. I would not recommend that choice. The clearance increase is minimal and it creates interference with the water pump so I had to reroute the oil return line.

I disagree with this assessment...

I changed oil return line 4 years ago on my early SN 120058 and used banjo fitting to gain much needed clearance to the muffler. Hose routing was not a problem.
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Just finished my coolant hose 5-year change out with silicone hoses. The thicker wall of the silicone hoses makes them tough to use because clearance is tight with the shroud on top of the engine.

What hose did you use that is thicker than OEM? The ones I specked are the same OD and use the same clamps. The elbow one is 4 ply and slightly larger but that is the only one.

I permanently removed the shroud on mine when I did the hoses. Vans said it didn't really work and it makes access to the top of the engine easier. I haven't noticed a difference in temperature with it gone.
 
I disagree with this assessment...

I changed oil return line 4 years ago on my early SN 120058 and used banjo fitting to gain much needed clearance to the muffler. Hose routing was not a problem.
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Jim has one of the early setups we did with a banjo return fitting. In order to minimize the profile even more, we now utilize a banjo fitting that is integrated directly into the hose itself. It has a slight downward bend in it which allows it to clear the case of the engine. Pictured below is the new setup in standard firesleeve.

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Pictured below is the new setup in integral firesleeve which gives an equal amount or slightly more clearance on the engine case.

Integral%20sleeve%20hose.jpg


IF the hose is installed upside down (with the bend up and toward the case) then there would likely be an interference issue.

As Jim showed in the pictures in his post, the increase in clearance is pretty significant between the 90 degree elbow and the banjo fitting. The 90 degree elbow being used absolutely works, but a low profile elbow is required and there is minimum clearance on the exhaust.

As always, if anyone is installing any of our hose kits and has any questions during the installation, or runs into any issues, please feel free to reach out directly via email or phone to Tom or I and we will work with you to get it figured out.

Steve
 
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Steve,

I bought my oil hoses a year ago, and the banjo fitting is straight which causes my interference. So I rotated the hose about 20-30 degrees off centerline which allowed use.

Jim,

I guess we have a different opinion on what is significant clearance increase.

Seagull,

I got the silicone hose online. I’d have to go back and figure out the manufacturer. Sorry, but it doesn’t rate high on my to-do list.
 
I guess we have a different opinion on what is significant clearance increase.

Per my photos in post #22 above: Stock elbow fitting is almost touching muffler. Banjo fitting has almost 1/2" clearance to the muffler. Now that is significant in anyone's book. Don't need to be rocket scientist to figure that out...
 
I got the silicone hose online. I’d have to go back and figure out the manufacturer. Sorry, but it doesn’t rate high on my to-do list.

Ouch, a little snarky.
I wasn’t really ask you but hoping you would answer so others reading would know which ones to NOT buy.
 
Seagull,
My apologies. I didn’t mean to be mean. I’m a little overwhelmed by all the stuff I’m doing this annual.

Rich
 
Steve,

Thanks for posting. I checked my banjo fitting today, and I did indeed install it upside down. Can’t believe I missed that. I know what I’ll be doing tomorrow.

Rich
 
Steve,

Thanks for posting. I checked my banjo fitting today, and I did indeed install it upside down. Can’t believe I missed that. I know what I’ll be doing tomorrow.

Rich

Rich,

No problem at all. Glad the pictures helped. We are always a phone call or email away if anyone runs into any issues with an installation or has any questions!

Happy building, (and flying)
Steve
 
Jim, Steve,

Thanks for this discussion about the lower oil hose. I checked to see if my fitting was inverted. Worse than inverted I have the old elbow and it is extremely close to the muffler.

oil line.jpg
 
As long as the elbow doesn't touch the muffler, does it matter if it is close?

Yeah, it does. Suppose on next flight one of the exhaust springs lets loose and muffler shifts position and then begins to rub on elbow. Perhaps even wears a hole in the elbow and a fire starts. See where I'm going here...?
 
I wrapped my muffler in insulation. It’s a thin exhaust wraps I bought on Amazon. I know ROTAX advises against this, but in Phoenix summer I have to do something or I’ll be overheating on climb out.
 
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