New oil cooler fitting and lines

[JHZR2]

After 35 years and 210k miles, an oil cooler fitting on my 1991 350SD looks a bit worse for wear.

I’m going to have to get the hoses redone, as I understand they’re NLA.

I had custom threaded fittings brazed on another set for my 1981 240D by a Parker shop. Thinking to do that again.

But any thoughts on the matter?

On my 81 the routing is a real bear around the ac compressor and motor mount, so making a replaceable center joint is a convenience factor. What I did there can be seen here:

Thread 'Issues using push lock hoses for oil cooler'

Sep 7, 2018

I wanted to replace the oil cooler lines on my 1981 MB 240D. Was already doing other maintenance, one connection was seeping a bit, and the rubber was original...

These lines are notoriously difficult to maneuver in and out, even with the engine lifted and an engine mount out. Many owners find other approaches to replace the flexible line section.

I went to my local Parker store and got Parker 836, which is good for oil at pressure to 300F. Nice and flexible. But it's a push lock design. The pressure rating is great and apparently the barbs are VERY aggressive...

Would anyone have...

• JHZR2
• Replies: 9
• Forum: Mechanical/Maintenance Forum

The routing and access for this application looks easier. Makes me wonder if just doing the threaded sections is really needed or if I just get new hose crimped on.

Thoughts?

 

[Sequoiasoon]

Somebody on here does custom hoses like what you are looking for but maybe A/C. I think @Chris142 did them. He may be a big help.

 

[oilboy123]

Yes those are hanging on. I hope you get it sorted out.

My old PU has an issue with the trans lines popping off at the quick connect from corrosion. Apperently an issue in the Rust Belt. I just bought a Dorman replacement, and will modify it to get rid of quick connects.

 

[JavierH19]

Not even a little weep surprisingly. I'd be shocked if I saw them that rusted given how rust free the rest is.

 

[Hohn]

After 35 years and 210k miles, an oil cooler fitting on my 1991 350SD looks a bit worse for wear.

I’m going to have to get the hoses redone, as I understand they’re NLA.

I had custom threaded fittings brazed on another set for my 1981 240D by a Parker shop. Thinking to do that again.

But any thoughts on the matter?


View attachment 341063View attachment 341066

On my 81 the routing is a real bear around the ac compressor and motor mount, so making a replaceable center joint is a convenience factor. What I did there can be seen here:

Thread 'Issues using push lock hoses for oil cooler'

Sep 7, 2018

I wanted to replace the oil cooler lines on my 1981 MB 240D. Was already doing other maintenance, one connection was seeping a bit, and the rubber was original...

These lines are notoriously difficult to maneuver in and out, even with the engine lifted and an engine mount out. Many owners find other approaches to replace the flexible line section.

I went to my local Parker store and got Parker 836, which is good for oil at pressure to 300F. Nice and flexible. But it's a push lock design. The pressure rating is great and apparently the barbs are VERY aggressive...

Would anyone have...

• JHZR2
• Replies: 9
• Forum: Mechanical/Maintenance Forum

The routing and access for this application looks easier. Makes me wonder if just doing the threaded sections is really needed or if I just get new hose crimped on.

Thoughts?

I have a lot of thoughts on this.

If you have access to a quality hose shop, they can crimp on the ends to any of several different hose sizes. You may already know that industry standard for fluid power is built around "dash" sizing which is 16ths of an inch nominal, making a #8 or -8 hose a half inch.


Danfoss (formerly eaton) makes arguably the best hoses on earth in terms of durability and reliability. They have a marine spec hose called FC234 that is rated to 150C and carries every safety and fire resistance rating you can imagine-- coast guard, ABS/DNV, MSHA. It' perhaps the best non-PTFE hose on earth for any hydraulic/oil/fuel application.


However, I would steer you towards using a push-on-barb kind of hose. Parker has an excellent and complete line of fittings (82 series) as well as several hose grades. The hose grade you want is the Parker 836, it has the highest temperature rating of any hose designed for push-on fittings. It carries an impressive 150C oil temp rating (and that's conservative) and it can be used with crimp on hose ends if you need that.

The hoses on there appear to be -6 size (3/8 nominal) and probably a flare fitting. Flares work obviously but they are metal on metal and not as reliable as a modern o-ring face seal kind of fitting. (SAE J1453). So, if you can unscrew the male unions in the cooler itself, it is not a bad idea to swap them for o-ring face seals if possible. If not, flare is fine, just be gentle on the torque.

The watch out is that flare fittings come in two common flare angles-- the SAE 45 degree flare (SAE J512) and the JIC 37 degree flare (SAE J514) and they share threads in some sizes! So you can accidentally install a 37 degree hose end on a 45 degree fitting and it will often screw right on and appear to be correct, at least for -8 size.

So pay attention to the details on these fitting and make sure the hose ends match your unions.

 

[GMBoy]

Have you tried the MB classic store:

https://classicparts.mbusa.com/v-1991-mercedes-benz-350sd--base--3-4l-l6-diesel

 

[Hohn]

With that much corrosion, I'd probably be tempted to replace the cooler entirely with an aftermarket unit. Preferably Setrab or similarly high quality.

I've been looking at the Derale 10000 series for a project of mine.