Cohline Fuel Hose Issues?

[EsGeht]

I am in the process of replacing 44 year old fuel hose with new Cohline 2122 cloth-braided hose, available from several vendors, as correct for fuel injection applications. I am, however, troubled by reports of dismal failure rates of this specific product, as per this thread: http://www.ddk-online.com/phpBB2/vie...hp?f=2&t=58033. Am I replacing good/old (and still not leaking!!!) hose with poor/new hose? Any experience with this hose, specifically Cohline 2122? Thanks.

[robmog]

I had rebuilt the fuel lines from pump to MFI and accumulator with cohline braided tubing.
They started leaking within a year.
I have since replaced with superseded non braidded Porsche new lines.
Not correct but no puddles of gas on the floor.
I thought mine was a unique problem, maybe not.

[EsGeht]

And here I am proud of the careful way I've used "correct" braided hose and proper oetinger clamps...haven't replaced any hoses under the car yet, just the engine compartment. Now I am rethinking the whole affair with "correct look" and going back to good ol' reliable rubber. But it looked so pretty. This is certainly not what I thought I was getting. Anyone else?

[chris_seven]

I posted the comments with regard to Cohline 2122 on the DDK Forum and we have had nothing but problems with cars running with carbs and 3.5 psi Hardi Pumps.

Cohline have been completely disinterested and have simply stated that we have exceeded the 50degC temperature rating.

We had exactly the same issue after 12 months with a Ford that travelled exactly 11 miles between annual Inspection tests and the leaks were in the boot area!!

Here is a recent statement from a Mercedes Forum:

Last hose they sent was COHLINE #2122. 0207(3.2mm X 7.0mm)

Anyone got an outlet on the correct hose, as this COHLINE lasts about 15 months or less.?



This is a photograph of the 'failed' hose we sent to Cohline.

Their comments were that 'the cracks did not penetrate through the wall' and so they did not consider that the hose had failed
They completely ignored our report that the car 'smelled strongly of fuel' and the braid was 'damp to the touch'.

The technician who prepared the report stated that the conditions of use were unknown despite us clearly specifying the location of the hose, the vehicle type and the fuel pressure.

This report in reality simply stated 'Foxtrot Oscar'.

I do have a reasonable background in Material Science and even the most basic literature search reveals that the Transport Research Laboratory in the UK has investigated the impact of Ethanol on fuel lines.

There is a mechanism involved that is fairly subtle - the presence of Ethanol in Gasoline increases the rate of percolation of the fuel through the wall of the hose.

It is not the cause of a crack but simply a diffusion phenomenon and the Ethanol increases the mass transport of the Gasoline.

It is then easy to see that as Gasoline percolates through the hose it will effectively condense into the braid.

The long term effect of this phenomenon is that Gasoline affects the rubber, produces cracking and as far as I am concerned produces a huge risk of fire.

I suggested this mechanism to Cohline via e-mail and the only response was to send a second copy of the initial report by e-mail.

This report is marked confidential so difficult to deal with on a Public Forum.

I must admit to being quite annoyed and I do want to share this information, it is not money related but wanting to eliminate risk to valuable cars and what I believe is poor quality technical support.

I would have considered Cohline as a responsible supplier who would be concerned about this issue but sadly this has been far from the truth.

If, however, the problem is temperature within the engine bay of a 911 then the product is still useless.

I do not believe that the problems we have had with this hose are related to either the air in our locality or the phase of the moon.

Aeroquip Startlite is Black Cotton braided, it has no over-printing it is rated to 150degC and is advertised as E85 Compatible.

There is a -6 size available.

Photographs of this hose on the web show a red trace woven into the braid but this has now been deleted and the hose is just braided black.

It is very expensive but we fitted it to car we service regularly (1967S) which lives in France and uses E85 fuel.

The Cohline 2122 we fitted lasted less than 3 months with this fuel and we replaced this with the Aeroquip hose more than a year ago and three weeks ago when we last inspected the car it was still perfect.


We now use a Codan material which is black cotton braided and is available in 8mm ID. It is rated at 100degC.

The braid quality and appearance of the Codan hose is much better the Cohline. When you cut the ends of the Codan the braid does not fray and remains attached to the rubber.

When rotated so you cannot read the over printing and it looks identical to the Cohline.

We started using the hose 4 months ago so I cannot make long term comments.

I am sorry to bang on - but we have had nightmares with this hose, many serious customer complaints and we will never use 2122 again other than for water.

We also believed we were doing a 'good job' and maintaining originality and we tried changing the hose for a second batch but with identical results.

I still have 40 metres which I will donate to any good cause

I have only one more comment to make with regard to this hose and using it on a valuable 911 - caveat emptor

[72targa]

Back in the very early '90's, I was helping my friend John Byrne put together his RSR. I decided to set out to get some original Dunlap racing slicks because I thought it would be really cool to have them on the car, even if just to show (Hoosiers were great but they were not Dunlaps as seen on some of the early sponsor stickers on the car). I found a Dunlap rep who could locate some in some far away place. He said he would sell them to us on the condition they would be used for show only (hardened due to age). Sometimes, you just have to do the right thing...safety first.

[EsGeht]

Thank you, Chris_Seven. For your posts on DDK and here. It is as I suspected, and I will replace all that brand new Cohline. I can't imagine anything more basic to safety than fuel hoses and this is absurdly unacceptable. Let the word be heard. Thanks for the lead on Codan as well. Jeez

[edmayo]

Who supplies the Codan hose?

[EsGeht]

http://www2.codan.com/node/28212
Just found this

[EsGeht]

Then saw "not to be used in fuel injection" applications. http://www2.codan.com/node/28212

[chris_seven]

It is an interesting note and we generally only use this type of hose on cars with carbs.

The working pressure and the burst pressure ratings of the Cohline 2122 hose are 7 and 30 bar respectively and this compares to the 8 bar and 32 bar of the Codan so in real terms both hoses have a virtually identical rating.

At the 1 bar max. of a typical MFI system I would tend not to be concerned but at EFI and Diesel Injection pressure ratings I would almost certainly use a reinforced hose.

For EFI main hoses we are using Gates 'Greenshield' Barricade

https://ww2.gates.com/europe/brochur...ation_id=19543

Gates do make a Cotton Braided Hose with similar ratings to the Codan product and again rated at 100 degC.

http://www.gatesunitta.com/en/gates-...se-4324-series