Oil cooler lines - PeachParts Mercedes-Benz Forum

Graham · #1 06-03-2020, 09:28 PM

I have had a small leak from the lower oil line at the cooler for ages.

Still need to clean it off and re-check, but it looks like it might be leaking at the cooler end swage . Perhaps at the cooler connection too. And that will require removal and possibly cutting of the nut.

Looking at new hoses, I only see only the top line available in OE from vendors including Pelican. Is that still the case? Did find one by Vollig. Heard of them?

Have read most of the posts about alternative fixes. Just preparing myself and investigating what I may be in for!

JHZR2 · #2 06-03-2020, 10:57 PM

Go to Parker and get some good hose attached on with fittings. Save yourself a ton of headache.

Graham · #3 06-03-2020, 11:09 PM

Is this something you have done? I would be interested in details on just how you did it. And what it cost vs buying OE type lines.

JHZR2 · #4 06-04-2020, 12:16 AM

Could have sworn I had posted about it on here, but cannot find it.

I went to Parker to get their specific hose (see link where I list it). They did the welding and whatnot, as that’s not my thing. Others on here have done it themselves because they have the skills to do so...

This is where I put a few pictures and wanted to get peer review:

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4862992/issues-using-push-lock-hoses-for-oil-cooler

Dont recall the Exact cost, but it was over $100. The issue was that no local hydraulic shops carried the hose that I wanted. Probably smarter would have been to get a local shop to rebuild the hoses with the right fitttings, and then just go to Parker or get a length of the right hose on eBay and get that retrofit...

But Parker is a one stop shop.

Graham · #5 06-04-2020, 09:53 AM

Ok thanks for that. All ideas are helpful.

What I see, is that doing it that way still requires R&R of the complete line - which is said to be difficult. And there is still the risk of damage to the cooler threaded nozzle when removing.

Buying a complete OE type line would no doubt be equivalent and preferred. But only the top line seems to be available from MB, and I would need the lower one.
That brings me to my question above about the aftermarket lines on eBay made by Vollig.

Avoiding R&R of the complete line, would favor using Diesel911's method of leaving the metal lines in place at both ends and hose clamping a piece of good quality/size hose in place of the existing swaged hose. However, if the leak is at the cooler union connection, then that connection would still need to be removed (with risk of damage)

Alternatives In summary:
1. Replace line with a complete OE or OE equivalent line.
2. Remove line and have hydraulic shop replace hose and re-swage.
3. Cut off swages and remove old hose. Replace with double clamped new hose.

First thing for me, is to thoroughly clean from end of hose to cooler, then watch to see where leak actually is.

If at union, buy a nozzle repair fitting from dealer before attempting to loosen the union. Tap should be available at short notice locally. Another thought, is to cut union nut off existing line and just use the cooler end of an aftermarket hose.

Question - How much of engine oil needs to be drained before disconnecting lower cooler line?

JHZR2 · #6 06-04-2020, 10:01 AM

So, yes... it requires remove and replace.

If your engine mounts aren’t new, they might be a good candidate for replacement, and that’s when removal is easiest.

I found removal to be ok, you can finagle them out. Replacement is the hard part, and if mods are made, it’s far easier. Plus you’ll never have to remove again.

If you’re worried about fittings being seized, then cut the rubber, pull the cooler, and have the addition of fittings be done all in one place. Again, you’ll never need to do it ever again, at least so long as you avoid collisions and rocks to your oil cooler.

To me, the oil cooler line replacement job is one of the most frustrating. Once you get it, it’s almost an aha moment where it seems so simple, but it isn’t. I can’t recall exactly how I got the full length hoses in there, and I’ve done it twice.

Not undoable, just frustrating. Since both my cars are keepers, I expect needing to do it again someday, which is why I went down that path in my 240d (300cd has OE replacement hoses).

Graham · #7 06-04-2020, 10:23 AM

Quote:

Originally Posted by JHZR2

So, yes... it requires remove and replace.

I found removal to be ok, you can finagle them out. Replacement is the hard part, and if mods are made, it’s far easier. Plus you’ll never have to remove again.

I missed the point about maybe having to do this again. That's no doubt where the Parker push-on fittings makes thing easier.

I have had '85 300D for 30 years, and this is first time the lines need attention. If repaired well now, the car and cooler lines will outlast me!

Just had another thought if cooler union nut has to be cut off - use the aftermarket line including hose back to the rear swage and clamp there. Just one clamped connection then. Will only work if aftermarket happened to use the same size hose. Would work with a real OE line.

JHZR2 · #8 06-04-2020, 10:55 AM

My point is to not cut anything metal. If you can cut the rubber partway, and unbolt/remove the cooler in full, then you could get the (threaded) fittings replaced on the rubber end, and then have the easy install. With no risk to your cooler, no need to cut off the fitting (which if that is seized or galled, probably means you’ll need to drill out the cooler fitting or else replace the cooler entirely....

Graham · #9 06-04-2020, 11:20 AM

Quote:

Originally Posted by JHZR2

My point is to not cut anything metal. If you can cut the rubber partway, and unbolt/remove the cooler in full, then you could get the (threaded) fittings replaced on the rubber end, and then have the easy install. With no risk to your cooler, no need to cut off the fitting (which if that is seized or galled, probably means you’ll need to drill out the cooler fitting or else replace the cooler entirely....

Maybe I am missing something.

I can see that if the cooler connection needs serious work, then cutting hoses and removing cooler makes sense.

But then what do I do? I am left with two cut hoses leading to the oil filter lines. I guess a union type connector could be installed onto old hose stub.
If I can split the cooler union nut in place or otherwise get it off, I could perhaps change the line from there back to the back swage. Only need to do one line, so cutting both hoses not preferred!

Thanks for input.

Diesel911 · #10 06-04-2020, 06:52 PM

There is at least 2 extensive threads on many methonds to replace the Oil Cooler Hoses.Repair Links
Fast navigation Fast navigation Do It Yourself Links

Other companies hoses on Ebay UK might get you a better shipping price.

People on that have bought aftermarket hoses have occasionally had problems with them.

If you are reusing your own fittings and replacing only the hose Cohline has the 15mm inside diameter oil cooler hose used on W123s.
Un the USA Bellmetric has the hose only. In Canada ???
I believe Cohline at one time also sold the complete Oil Cooler Hose assemblies.

See the attached pic of the hose part number and size

Diesel911 · #11 06-04-2020, 06:54 PM

Here is my old thread. My original pictures are gone but others have chimed in with their methods.

My Oil Cooler hose Thread Cheap oil cooler hose replacement.
Cheap oil cooler hose replacement. - PeachParts Mercedes-Benz Forum

Graham · #12 06-04-2020, 07:24 PM

Quote:

Originally Posted by Diesel911

There is at least 2 extensive threads on many methonds to replace the Oil Cooler Hoses.
See the attached pic of the hose part number and size

As mentioned in my first post, I have read most of those threads. Many alternate ways of fixing. Hose part number and size useful!

The warnings about difficulty in installing a replacement hose are what alerted me to look for other ways.

I checked my leaks today. Looks like some seepage at both ends of rubber hose as well as from the lower union on the cooler itself.

If the existing lines were easy to get in and out, this wouldn't be a big problem. To do it your way, with hose and clamps, I still have to get the bottom union off without damage, because it is leaking. May be hard to re-seat.

The extensive info on this site has at least let me understand what the problem is and where the pitfalls are.

Conclusion is that the lower rubber hose must go. Maybe the cooler metal end as well. Which leaves me with the aftermarket complete line, unless I can remove the lower line and install a replacement. Or I just live with a small leak.

Junkman · #13 06-04-2020, 08:19 PM

I replaced a set on the 84SD with one of the aftermarket hoses and it is still not leaking. Replacement required holding things just right and twisting/turning until it worked. It goes but is not easy and easily forgotten so I'll have to figure it out again if it ever leaks.

The other I converted to AN fittings per one of the threads. It was easier to install but hard to find the parts and I had to have one of the local welders put the parts together. That process was also not really easy. The redo would be easier than replacing with OE.

I'm not sure what I'll do the next time. Both hoses need to come out to do the bottom hose so I would only do the job if willing to replace both hoses. One goes, the other isn't far behind.

Graham · #14 06-04-2020, 09:00 PM

Quote:

Originally Posted by Junkman

Both hoses need to come out to do the bottom hose so I would only do the job if willing to replace both hoses. One goes, the other isn't far behind.

Is that true? I looked at it today. There seem to be two clamps. The lower one appeared to be on the outside (away from engine), so I figured that it should come out if the clamps were released.

The upper hose looks fine, so I wouldn't change it and would not want to disturb it. I am sure it will outlast me

Diesel911 · #15 06-04-2020, 09:36 PM

When you have a leak between the collars and the hose it means the rubber hose has lost elasticity. A couple of people have had the hose come out from under the collar while they were driving.