Replacement return lines: Tygon?

Hi all, I was going to put this in the 6.2 cause that is what I have, but figured it may also be pertinant to 6.5 as well since i believe they have return lines off the injectors too. Anyway, i did search first too. I read somewhere here where the good Dr. recomended using Ester (I think, pretty certain it started with an e) based hose material for clear return lines and was so good as to include a McMaster Carr part number and pages. I have some Tygon tubing, which is apparently good for "most" inogranic solvents, but I am uncertain how it would work with Diesel fuel and/or B100. ANyone have any experience with using the stuff for return lines? We have tons at work and it ends up pitched out all the time, so the price is right. Thanks in advance.

I have a friend who uses Tygon for this purpose on a 5.7L Olds(Yep, still running!) with good results. However, it is a different diameter and may not get as hot as those on a 6.2. How about trying one somewhere easily accessed (front driver's side?), to make it easy to inspect for heat damage, stertching, or other problems (then, cause you're a good sport, let the rest of us know what happened).

I need to make a change on my 6.5 due to poor service both of the ones from my local Stanadyne supplier and from the dealer, and, MAN, you don't want to have failures behind the turbo!!! Other experience out there? Surely someone has a tried-and-true long-term solution!

The other problem is to find a tubing system which doesn't require clamps, because they exacerbate the problem considerably. (Do Real Mechanics have reeaaaallly skinny, strong fingers with extra joints in them? Cause that's what it takes sometimes...I wind up with extra joints afterward!!! :-) )

There are several outfits that advertise return line kits on line.
I used a local supplier for them the last time through and have had zero issue.
The lines I got are a braid covered and dont need the clamps.

Hi Robyn...

The fabric, non-clamp ones are some that have failed with me. Perhaps I expect too long a service...or maybe these are inferior to the ones you have used. They slip on nicely and hold in place, sans clamp, until the ends eventually harden and crack, and leaks follow. Then comes the big clunky hands problem, trying to install new without dismantling the turbo side of the ingine!

The lines I get come from the local Detroit Diesel shop. I would guess a set gives 40- or 50,000 miles. Where do you get them? Are they Teflon(R) lines? I think those are available somewhere.

Thanks

they have return line kits HERE

Thanks, Murphyslaw...I'll check John again to see if his are the same fabric-covered ones I am using. If so, the service life has been poor, in my experience. And, I can buy the tubing in bulk locally at less than $1.00/ft (can't recall exactly)...don't need copper seals or airhorn gaskets that come with the kits.

I can't recall where I saw the Teflon-lined ones earlier. It's worth a try to find that material again. What is your experience regarding service life of the tubing? With 610,000 on two Suburbans, you can imagine that I go for something with low maintenance and attention requirements!!! Not to mentions retiree income problems, as D*P*** continues to erode my meager no-COLA pension.

Thanks for the followup.

I have about 140k on the lines that came with kenedys kit. just checked 'em out a few days ago and they still looked brand new besides from having to scrap all the mud off em to see.

I will get some tygon from work and try these over the holidays. Will post after we see how they do. Thanks to all for the input.

We use tygon with Jet A and it seems to hold up ok . Not sure about the heat issues though. I will put a chunk behind the turbo to see how it holds up.

I had a fuel leak a couple of weeks ago, and as a result needed to replace my return lines. I looked all around town for some suitable hose. I ended up with a few options. I also decided to do some heat testing on all of my available options, here is what I found.


My testing included:
GM part #14066305 ($14.50= 9 inches)
Dorman part #904-101 ($14.99= 72 inches and clamps)
100% Viton 75a ($3.00= 12 inches)
Braided "kit" hose "made in Germany"(~$25 includes gaskets etc)


I did this "testing" while my wife was out of town and so the oven was free to use. I cut 2 inch lengths of each of these for samples and laid them out on a sheet pan. The oven was checked for temperature accuracy and then the testing began. All temps are in Fahrenheit, temperatures were sustained for 30 minutes, each hose was bent and squeezed at each check. The results are as follows.

200- no change in any of the samples
250- no change
300- beginning to smell rubber
350- strong smell of rubber
400- Dorman hose cracks when bent
braided hose separates from braid and begins to swell
GM and Viton begin to harden
450- Braided hose swells and cracks
GM and Viton hoses crack when bent


An interesting note, the GM and Viton hoses were the only ones to return to the original flexibility once they cooled down. The others remained hard and brittle.

I have no info on tygon hoses but I hope this information is helpful to someone. Also, the hose clamps can be had for ~$5 dorman #90099, if you need them.

Get a Depaco line kit, these are top quality and come with the lines, the end caps and the copper rings for the injectors too.

You can find them even on ebay.

I have uses these myself and would again in a heartbeat.


Robyn

I asked a local diesel shop and he just used the fuel line from the local lawn mower shop. So that was where I went and have yet to have a problem. It is a yellow transperant line that is still somewhat soft and flexable just as the day I put it in. I got 10 feet of it for IIRC 6 bucks. The guy at the mower shop said it was used for the chain saws that come through his shop. Those are the heavy duty ones that have the small bars in the 30 plus inch range. They get pretty hot during use. The local crappa shop wanted 95 bucks for the install kit. After looking at the lines and asking the dumn questions I left and went to the mower shop.

Hope this helps some

John

I used translucent yellow Tygon line (sleeved with regular fuel line as suggested by Robyn) on the turbo side of my rebuild. Only have 1000 miles on them, and this summer should test them. The nipples on the #4 injector would not line up horizontally and trial fitting the heat shield showed that the shield would be in direct contact with the lines.

To get the nipples to line up, I swapped the injectors around until I found one that would seat with the nipples horizontal. It was a PITA and I should have done that when the engine was out of the truck. Also used plastic tie straps to pull the lines a little farther from the heat shield. And a piece of Tygon on the fuel return line coming out of the IP. You can see air bubbles going through it if you have a leak in the system.

Have had the tygon lines on my rig for 18k miles now and 7 years of service under all weather conditions. No issues.

I have never used the tygon "see though" lines, but usually use the OEM type replacement lines that are sold though the injector shop I used to rebuild my squirts.

The last kit I bought was "Dipaco"

https://www.google.com/url?sa=t&rct=...zhTk0wDNseyJ4g


Braided lines, end caps and other goodies in the kit.

Not sure how well the see through lines are gonna hold up on the long haul in the high heat though

I buy my braided injector return lines from my local import auto parts store.
Both my Mercedes diesel and Chevy's use the same size return line. I usually buy in bulk. Meyle brand has worked well for me. 3.2mm is 1/8 inch. The owner of the parts store has had the best of luck when his customers use the VW end plug. They are a solid design, and less prone to failure.

HammerWerf

We stock the return line kits as well.

http://www.kennedydiesel.com/detail.cfm?ID=41