The joys and sorrows of removing oil cooler lines
 

As some of you know I'm "rebuilding the 82 300TD to be a reliable daily driver.
Suspension is done all fluids have been removed. All filters replaced. Round of new glow plugs for each cylinder on me. All rubber lines have been replaced. Valves adjusted. And today I had the distinct pleasure of removing the oil filter cooling lines. They were leaking and creating a mess for the last couple of years that I drove the car.
Well its a job.
Remove the connection on the cooler. Of course black oil drips everywhere. Then release the lines on the oil filter. Quite a few things are in the way so its a tight fit. And of course its 27mm wrench which with all my tools I do not have. So I used an adjustable wrench. Got them loose and more black oil. But this time I did not have the oil pan under the filter section because it was still collecting the drips from the cooler.
To remove the lines I figured I would try to get them out without removeing a lot of things. FORGET IT.
To get the lines out you have to remove the engine mount off the block. To remove that you have to remove the allen bolt holding the engine mount etc. etc.

Let me summarize.

Remove the inline filter to the injection pump and the hose from the fuel line. You may consider removing the cigar hose also. Additionally I have a lot of the vacume lines removed right now along with th etrottle linkage on the top of the valve cover.
Remove the windshield washer tank.
Unbolt the 2 places that the oil cooling hoses are clamped together. A 10mm? socket with a universal and a 18" extension.
Support the engine with a hydraulic jack under the oil pan with a block of wood between the jack and the oil pan.
Have 2 drain pans to catch the oil . Unbolt the lines at the cooler and the oil filter. The oil cooler will drain onto the body spoiler then into the pan. The filter connection will of course make a mess.
The lines will now be free. Consider cleaning the ends and taping them up with duct tape or something. More oil will come out as you twist them to remove them.
Place a hydraulic jack under the engine with a block of wood between the jack and the oil pan to support the engine. Unbolt the allen bolt from the bottom up into the motor mount.
Disconnect the engine shock. To do this another wrench is needed that is not usually included in wrench sets. A 7MM wrench.
The bottom and top bolts are 10MM the wrench to hold the shock shaft from spinning is the 7mm. Again I don't have one. However a 8/37" wrench will do.
Remove the 4 nuts holding the engine mount to the block. I used a 17mm socket and a breaker bar. Teh front lower bolt required an extension the other 3 didn't. To completely remove the mount you have to disconnect the power steering line that is blocking the mount. Its the one closes to the mount. I quickly removed and replace the hose as I pulled the mount out of the way. More fluids to drip on the ground.
Move the lines as necessary to remove them from the car. I have cleaned them up in the wash tank and will have new rubber sections installed at the local hydraulic shop. I'll price them first. New iol cooler lines are $45 each at Fastlane. I also removed the oil cooler and cleaned it in the wash tank. It seems to be in fine shape, thank God, Its $375 at fastlane.
Now that 1 motor mount is out. I'll replace both since its not that hard.
The job is a bit of a pain. Messy more that anything. Lots of fluids dripping everywhere. and the unusual size wrenches. 7mm and 27mm box, a flare wrench would be better for the oil line fittings.
When installing the oil lines. Use 2 wrenches on the lines. Each port has a place for 2 wrenches to be use for this.

Dave

This may not be the time to tell you, but I seem to recall a post from last fall describing how it can be done without all that effort. Anyone else remember that?

While you have it all apart, why not replace the O/F housing-to-block gasket? Now is the time to do it. And while you have the O/F housing off, replace the seals at the cooler hose connections on the housing. Those fittings are 24mm. Also get a new gasket for the back cover plate on the housing. The part numbers are as follows:

616-184-07-80 (housing-to-block gasket)
617-184-01-80 (rear cover plate gasket)

Also, it sounds to me like you removed the entire engine mount arm, rather than just the mount. The lines can be removed by just removing the engine mount rather than the whole assembly.

One last thing; Be careful when you retighten the cooler lines back on the cooler itself. Those threads are aluminum and strip easily!

If you decide to go with factory cooler lines, here are the part numbers:

617-180-05-82
617-180-01-82

Nope, Kerry, this sounds like SOP for a 123 oil cooler line replacement. This is one of a bazillion reasons why I've grown to dislike the 123 chassis and periodically go hug my two 124's (they have nearly bulletproof oil coolers & hoses). :D :D Note that I have owned several of each, and do all my own work on them. Can't wait to trade out the 123 for a nice 201 or 124...!

Ridiculous. I have a lower line that is ever so slightly seeping, not dripping, not really wet, just that oil stain. Was considering replacement until I read this.
I have two suggestions:
First-Remove lines at oil filter housing. Point one end into empty milk jug, blow compressed air into other end. Should get most of the oil out of the lines/cooler.

Second-Remove leaky lines by cutting them up with pipecutter, sawsall, etc. Take hose ends down to local Aeroquip/Russell/Earls dealer and pick up the correct metric-to-AN adaptors, AN fittings, and about 7-8 feet of braided stainless steel oil hose. -6 or -8 line/fittings should be more than adequate but take a section of hose to show the dealer to be sure. Install lines, route them any way thats practical and never worry about it again. If its good enough for aviation and NASCAR it'll be fine in a MB. Cost you $100-$150 and much easier to do. The added bonus is they will NEVER fail in normal automotive use. RT

You can in fact snake new oil lines in without removing the mount, it just takes forever if you don't pay attention to how they came out (don't ask me how I know). Disconnect both ends and wiggle them around until you get them out, one at a time. If I remember correctly they work in from below and behind the mount and one is substantially easier than the other. Not sure it's a big time saver though.

Don't think I'd go the NASCAR route on something so critical. Remember, these lines last a long long time. I just did mine a few months ago on the '83 300SD at 251K miles. I'd suggest sticking with dealer items on this job.

Don't think I'd go the NASCAR route on something so critical.

Here we go again... If it ain't built by MB it ain't good enough. What a pile of crap. Absolutely nothing wrong with going aftermarket. Its obviously a "critical" part. Thats why I suggested using a replacement that FAR EXCEEDS any MB standard past, present or future. These are aviation grade, as in-FAA approved, can't fail, bulletproof lines. Stock MB lines may be fine but there is absolutely no way that they will pass to FAA standards. This keep-it-stock mentality drives me nuts sometimes. Stock happens to be 20yr old thinking. I think anyone can see we have come a long way since then. Keep whats good about the old ideas and utilize the new tech when we can. That or stick your head in the sand and be a Luddite. At the very least a hydraulic shop can replace the leaky rubber lines with crimped-on braided stainless. There is no way you can argue that ain't an upgrade. Rant off. RT

Aircraft hoses, etc.
 

Oh, my. I shouldn't get into this, but....

I've been an aircraft mechanic since the Dark Ages.
Some people think aircraft hoses never need to be changed. Some even fly. And every year, several of them settle on freeways around the country with seized engines.

Most aircraft manufacturers I know of recommend that flammable-fluid-carrying hoses be replaced every FIVE years or so. At twenty years, in a high-temp environment, they will break like glass. I know this. I have seen this. Stainless steel braid is pretty, but the braid doesn't hold the liquid in. The liner does.

Teflon-lined hoses will last longer, as long as they are not disturbed. If disturbed, all bets are off.

Dunno much about NASCAR, but have heard those cars are only used a couple of years. Braided hoses will last that long, I suppose.

This is becoming an odd thread. I thought the recommendation by rwthomas1 was pretty good.

The small section of hose length is needed to provide flexibility between the cooler mounted to the car body structure and the connections to the oil filter housing, mounted on the engine. The engine shakes and bounces around enough that a solid metal line would not work. This bouncing, the heat and the pressure cycles are what eventually lead to hose failures.

MB hoses are not designed to last the life of the car without replacement any more so than the aircraft hoses. In fact, the five year replacement periodicity for hoses in general is intended to ensure there is never a hose failure in service, under any normal operating conditions. There is also usually a shelf life for critical application hoses after which the hose is not allowed to be installed for the full five years. This periodicity is common in all military applications as well as the commercial aircraft applications where "normal operating conditions" can be pretty strenuous and the consequences of a failure can be catastrophic.

If asked, I believe the MB engineering advice would be to replace them at the five year period as well. There is nothing to be gained for MB to suggest the hoses should last longer on their cars when the industry standards for rubber hoses makes it clear the 5 year period is the safest way to go. We, as owners elect to wait until we see visual signs of a failure taking place before we change them. So we elect to exceed the industry standard on our own. Our motivation is usually first that we tend to be frugal, and second the job is such a PIA.

The features of rwthomas1's recommendation that I found of particular merit were that he addressed both of the big problems. Once you decide to do the job and scrap the old hoses, you can cut them up to get them out. The replacements can be lower cost, and they can be easier to remove and replace. If the new parts are mostly hose, they can be more easily manipulated to get into position. You can still wait for them to fail like the MB units and the replacements will in all likelihood last a similar length of time provided you buy a quality grade of hose, or you can elect to perform a preemtive strike on the hoses and replace them just because they are five years old. But you can do it yourself and if you make the design so replacement of the hose section is inexpensive, the job won't cost an arm or a leg.

I find this argument a lot like the "Topsider" oil change issue. If the job is easier to do you are more likely to do it at a reasonable interval. I think it is more important to replace the hoses before they fail catastrophically than to use OE hoses, if that would be a barrier to doing the job. Same with the "Topsider" issue. It is more important to replace 99% of the oil at reasonable intervals than it is to get 99.5% out but do it less frequently.

Hope this helps, Jim

I too loved RT's idea... and I would also like to do that to the Radiator Hoses... anyone have a source for those ? I mean actual ones.. not the 'covers' some performance shops sell....

Concerning Veggiepups statements , which I believe are all true, what the braid does help protect against... things like fan blades giving way and slicing the oil line... or other stuff contacting the outside of the line which might cause it to fail....make for more peace of mind out on the road in a twenty plus year old car....

Okay, I got a little hot under the collar there. Sorry. It just seems like the stock hoses are a PITA, period. Replacement with something like Aeroquip, etc. would surely be easy and likely about the same price. An additional benefit is the abrasion resistance and the AN hose ends are usually reuseable so when replacement time comes around again all you need is more bulk hose. Just trying to think outside the box. You know the one, it has MB labels all over it.... RT

Well said, Jim Smith!

I had the good fortune of replacing the oil cooler hoses on my 240D a few months back. :D Yes it was difficult but I eventually got them in. It's all by trial and error. One thing that I did do is cut the cold rubber hoses to let all the oil out of them before I even tackled the job because I knew it would be messy if I didn't cut them.

Herb
'82 240D
'87 300SDL
'92 300D 2.5 Turbo

Having actually done this repair I can honestly say that the lines do indeed come out without removing any other part of the car(save the actual clamps that hold the lines). It can be like trying to do a bad puzzle after having a few beers but it is very possible to do. Take as many deep breaths as you need and keep telling yourself it can be done.

The biggest problem is getting the lines back in, by this I mean in the proper location as far as the lower bracket is concerned. My biggest problem was that I would look at the lines from the top but try and put them back in while lying on my back. If you don't get the lines in the right place on the lower clamp your screwed and have to take it out and try again. I think some color tape(or any tape) to help identify each line would help. Knowing the exact routing before getting the lines out will also help, taking a picture would be even better (again tape on one line comes in handy here).

As for the aftermarket lines from the aircraft industry I have these comments. If replacing the lines every 5 years prevents a failure and the new lines can be easily replaced, go for it! My only concern is the ability of the lines to withstand all the vibration and movement. If these lines go brittle with age they will surely rupture if left in too long as there is a lot of movement from one end of the line to the other.

One final note, I had a bi*&%^ of a time trying to buy a new line from any source. Nobody had them in stock, MB had to order them from Germany!! From what I read it would be possible to have a local shop replace the rubber sections. Of course the nut on the oil filter end of my hose seized to the line and the fitting in the oil filter holder. The steel section of the line got twisted. I had to hack saw the POS to get it out, was not a good day!

Boy, talking about opening a can of worms.

First
The job was a pain while trying to LEARN how to do it. The lines are 23 years old. I replaced them because I was there and figured I would do it so I don't have to worry about the seepage that the line was doing. That black oil sure does make a mess, as you all know.

Second
If I were to replace them again I would remove the motor mount arm as I did. It was not that difficult to do once I decided to do it. Sometimes the job goes easier if you take the things off the car that are in the way instead of trying to figure out how to do it without removing everthing. You can actually spend less total time doing it the right way instead of trying to figure out how to get around it.
I brought the hoses down to Kims Hoses in Ft. Worth. They charged me $34 to repair both hoses. A lot cheaper then Mercedes and Fastlane($90). Will they last 23 years as the OEM's did, who knows!!

Third
I would be a little concerned about using flexible hose for the entire setup. The metal hoses are designed to route in a particular way and I would be concerned with the hose touching the block, getting hot and leaking.

Forth
AN fittings. Yes they are aircraft designed and strong.
As a Captain for Amercian Airlines, The only engine shutdowns I have done are for oil lines breaking. We lost all our oil and had to shut one down, twice. I have never shut down my Mercedes for a broken oil line!!!!!!!

Fifth
Consider a C check in the avation industry. After so many hours of flying we completely rebuild the aircraft. Not just check it. It is completely taken apart, gutted. Everything that can be removed is removed rebuilt or replaced. If you did that to your Mercedes every 5 years think how nice the car would be. Thats what we do in the aviation buisness. So when you get on an aircraft that is 20 years old. Realize that it has been rebuilt, or restored about 4-5 times depending on how much the Airline flys the Aircraft each day.

Sixth
If I were doing the job again. I would
Jack the car up and place it on stands.
Remove the fuel line to the IP with the inline filter
Remove the cigar fuel line.
Disconnect some of the vacuum lines to get them out of the way.
(you always have to move the vacuum hoses out of the way in the diesel, even if your changing a tire you probably have to move the vacuum hoses *G*)
Remove the windshield washer tank
Place a jack with a wooden block under the oil pan
Release the engine mount and shock. And the throttle arm ( See thomaspins web site on engine mount replacement
( http://www.pindelski.com/ )
Jack the engine up
Unbolt and remove the engine mount arm ( only 4 bolts and can be done from above). Disconnect the power steering line to remove the mount, then screw it back on to stop the fluid from dripping.
Unbolt the oil cooling lines, including the 2 mounting supports, and allow them to drain. ( you could do this first to allow time for them to drain) Then tape them shut to stop the dripping mess
Lift the lines up from the top. They will come right out. Very little manuevering required now.
Take them down to Kims to have them rebuilt, which may be difficult for those who don't live in the DFW area *G*
Reinstall in the oposite order, The inside or upper hose first.

Dave