Radiator Hoses

[bobcharl]

Am presently carrying our the 5-yearly hose replacement procedure.

Having trouble locating suitable hose for the two radiator hoses. seems they are not a Rotax part. Bought some Continental brand hose last time and it was quite successful, but I have not yet been able to source it this time. lots of automotive hose in silicone, but it is too soft and tends to flatten/kink on the curves.

Apparently Savannah now come with a flexible stainless steel tube. I have some concerns about this in regard to potential chafing. Anyone had any experience, good or bad with this.

What is everyone else doing re radiator hoses at their 5-yearly.

All comments gratefully received.

Bob.

[Moneybox]

1 hour ago, bobcharl said:

Am presently carrying our the 5-yearly hose replacement procedure.

Having trouble locating suitable hose for the two radiator hoses. seems they are not a Rotax part. Bought some Continental brand hose last time and it was quite successful, but I have not yet been able to source it this time. lots of automotive hose in silicone, but it is too soft and tends to flatten/kink on the curves.

Apparently Savannah now come with a flexible stainless steel tube. I have some concerns about this in regard to potential chafing. Anyone had any experience, good or bad with this.

What is everyone else doing re radiator hoses at their 5-yearly.

All comments gratefully received.

Bob.

 

Skippydiesel has posted a lot of details on radiator hoses. I just Googled the automotive sites for mine and got every hose to fit without changing the bend.

 

 

[BrendAn]

On 12/02/2025 at 11:15 AM, bobcharl said:

Am presently carrying our the 5-yearly hose replacement procedure.

Having trouble locating suitable hose for the two radiator hoses. seems they are not a Rotax part. Bought some Continental brand hose last time and it was quite successful, but I have not yet been able to source it this time. lots of automotive hose in silicone, but it is too soft and tends to flatten/kink on the curves.

Apparently Savannah now come with a flexible stainless steel tube. I have some concerns about this in regard to potential chafing. Anyone had any experience, good or bad with this.

What is everyone else doing re radiator hoses at their 5-yearly.

All comments gratefully received.

Bob.

are you talking about the 17mm hoses.

[skippydiesel]

Hi Bobcharl,

 

I have no comment on the corrugated metal hose supplied with some kits.

 

All the information you need, to purchase non OM hoses, meeting Rotax specifications, can be found in  "Started a spare parts list" for 17mm & 25 mm coolant hoses plus fuel & oil hoses.

Unfortunatly there is quite a bit of tangential discussion to wade through but it's there.

If you are can't find it/unsure - get back to me😈

[bobcharl]

Thanks Skippy,

I cant find the list, is it in this forum or elsewhere?

Your help would be appreciated, but keep it simple as I am not very IT literate.

Bob.

[bobcharl]

Hi BrendAn.

 

Talking about the 25mm radiator hoses.

Bob.

[IBob]

bobcharl, the flexible SS radiator 'hoses' work fine. My kit was despatched Dec 2014 with them ,and so far as I know they are still supplying them: if there was a problem I'm pretty sure we would have heard by now.
To avoid chafing, it's not difficult to secure them with cable ties, threaded through a short 'bead of regular hose to space them from the securing point.
And they have the advantage that you can work quite a tight bend into them without flattening or collapse, as regular hose does when bent tightly. So makes for a very neat compact installation.
You still need regular hose and hoseclips to make the junction at the ends.

Edited February 13 by IBob

[Moneybox]

7 minutes ago, IBob said:

bobcharl, the flexible SS radiator 'hoses' work fine. My kit was despatched Dec 2014 with them ,and so far as I know they are still supplying them: if there was a problem I'm pretty sure we would have heard by now.
To avoid chafing, it's not difficult to secure them with cable ties, threaded through a short 'bead of regular hose to space them from the securing point.
And they have the advantage that you can work quite a tight bend into them without flattening or collapse, as regular hose does when bent tightly. So makes for a very neat compact installation.
You still need regular hose and hoseclips to make the junction at the ends.

It looks like you have very little hose to fuel filter connection?

 

[IBob]

Moneybox, I have just been advised that the filters you see there are no longer to be used.
So, I'll be getting onto that. The hose is the correct size, as I recall, for the splitter and the carb spigots. I can't tell you offhand what size it is.
I can tell you that I did the original flow testing via them, and it was very much more than adequate.

[Blueadventures]

These are the silicone hose and alloy pipes on my 912ULS coolant setup.  (Note the image of port side of engine is an old one and shows the black rubber hose, its changed to blue silicone years back and I'll get an up to date image.)  The alloy coolant pipes are great and from Flylight Airsports in UK ; they are great and reduce the long lengths of hose that some people use.  (The exhaust wrap is a mix of white and gold colour tape.)

Edited February 13 by Blueadventures

[skippydiesel]

I see worrying matters in the above photos (Blue & IBob).

• The corrugated oil & coolant lines & the alloy coolant pipes require at least two additional joins /pipe, compared with a single "rubber" hose - this introduces unnecessary potential failure points.
• The use of "plastic" filters within the engine bay is strongly advised against.
• The use of pleated "paper" filters is also strongly advised against.

 

[IBob]

Skippy

1. Unnecessary potential failure points. I agree that at first sight 'rubber' termination of metal hoses could seem, in principal, messy and over-complicated. I guess that should be weighed against the benefits in practise.....and whether these additional points do actually fail. In practise I feel the metal pipe does a good job of making the required shapes in the Savannah engine bay. And I'm comfortable with those terminations.
2 & 3. Spot on. As noted above, another member here just pointed out that those filters are no longer acceptable. I have thanked him.......and now you......and will sort that out.

[onetrack]

For bobcharl - here is the link to the discussion, "Started a spare parts list" ...

 

 

[skippydiesel]

1 hour ago, bobcharl said:

Thanks Skippy,

I cant find the list, is it in this forum or elsewhere?

Your help would be appreciated, but keep it simple as I am not very IT literate.

Bob.

Scroll down to Aircraft General Discussion open Scroll down to Start Spare  Parts List

 

There is a lot of tangential debate , consider it educational.

 

My recommendations are all for Gates hoses, most  (fuel/coolant) of which can be obtained through  REPCO, with the exception of the oil hose which comes from Hydrolink

 

"For fuel line I use Gates Barricade EFI (also known as MPI) this is overkill for pressure rating but has slightly better temperature & permeability. This is compared with the Barricade Carburation Hose, which also meet the Rotax specifications. Comes in a range of ID's - there will be one to suit your application. Be sure to get the right size, cut carefully (I prefer to cut, so installed length is covering the whole length of the spigot at each end. Use a hose cutter for nice 90 degree clean cuts and blow through with compressed air before installation)."

 

 

"Seems that there is nothing available (except from Rotax) in straight hose BUT you can purchase the following molded/shaped hose in 16.5 & 17 mm ID which can then be cut to the required lengths.

Note: Most installations will require a little over 2m in total, you will have to purchase more than one of the preformed hoses, so be sure to compare the total price with Rotax supply.

 

02-1579  16.5mm

02- 1249 16.5mm

02-0912 16.5mm  x 755 mm long

02-1415 17.00mm x 280mm long (see below)

 

Gates Silicone comes in ID 16mm (5/8) straight & formed. Silicone hose is usually super stretchy, so I assume  16mm will push on to a 17mm spigot/barb. 

https://www.gatesaustralia.com.au/-/media/files/gates-au/heavy-duty/application-data-sheets/heavyduty-product-range--silicone-coolant-hose.pdf"

 

"Check out Gates 01 -007, 03-0010 & 03-0011,  multi fit, 25 mm ID, coolant hoses"

 

"Oil - Gates  8- GTH hose from Hydraulink. Be sure to order correct ID for your application."

[danny_galaga]

5 hours ago, onetrack said:

For bobcharl - here is the link to the discussion, "Started a spare parts list" ...

 

 

Hey! My hand is famous ☺️

[bobcharl]

Thankyou everyone for your thoughts on this matter.

Did like blues solid pipes, but have some doubt re cowling clearance on the port side, and don't really want to wait for a delivery from the UK, so have decided to go with the SS corrugated tubing from ICP. Acknowledge the fact that they create a couple of extra joins on each side, but don't see that as a huge issue.

Have only been able to source positive comments on these, and in the absence of any negative comments think that this is a reasonable decision.

Thanks again,

Bob.

[skippydiesel]

I wonder - does corrugated pipe have a greater flow resistance than smooth???😈

[IBob]

There are flow rate calculators for both types on line. I haven't run the exercise, but the corrugated pipe supplied with the Savannah is presumably sized correctly, as it has no problem providing adequate flows and cooling.
I believe corrugated pipe does have a sharper 'cutoff' once laminar flow is lost due to liquid velocity. Which would make sense.
 

Bobcharl, as I recall, with the pipe that goes up to the coolant reservoir, I had to complete the shaping of it in place, as when I preshaped it I then couldn't thread it into position.

[skippydiesel]

FYI - On Fuel Filters

 

For anyone wishing to upgrade from pleated "paper" media filters - I have a small number of Hengst  H102 WK & H 103 WK, gauze media, fuel filters. 

 

 

 

[bobcharl]

 

Yeah Skippy, had considered the possibility, but don't expect it to be a problem in my case. Have had difficulties in the past with cold running - have to blank off both radiator and oil cooler according to season.

 

iBob, thanks for the tip - can see how that would happen.

[skippydiesel]

3 hours ago, bobcharl said:

 

Yeah Skippy, had considered the possibility, but don't expect it to be a problem in my case. Have had difficulties in the past with cold running - have to blank off both radiator and oil cooler according to season.

Dont know you aircraft or situaton however you might like to consider restricting exit air flow,  rather than individually blanking off heat exchangers. With my last aircraft I had a winter & summer fixed cowl flap ( aluminium sheet, shaped to fit, held in place by 10 small nuts/bolts) - worked a treat.😈