This is a nearly 7 thousand lb vehicle that is geared low.... it allways puts a load up on the engine.

Anyone disagree? This sounds to be my best route.

My concern is the design of the thermostat. Ifffff it's design is to open one path of oil to the oil cooler while simultaniously closing the other path that the oil flows (when its cool) then blocking with a plug after the thermostat creats a closed circuit.. Nottttt good.

How do I identify which line is the oil "out" of the engine and which line is the oil "returning" to the engine?

I broke an oil cooler line on my Euro 450SEL and tried to patch it up to get home by inserting a nipple and tightening two hose clamps on it. It leaked like a sieve. I good not get the clamps tight enough not to leak.

I did get home because I had three quarts of oil in the trunk and was only about four miles from home.

I discovered the leak by accident and was in a hardware store parking lot when I discovered it.

I ordered two new hoses the next day and installed them the day after that.

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Mike

2000 SL500 22,000 miles
1981 300CD 188,000 miles
1979 450 SEL 266,000 miles
2005 Cadillac CTS 25,000 miles

There's the obvious simple but messy test.

Someone on the list posted a link to a source for metric fittings a few weeks ago. Was it Leathermang or Engatwork?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Sorry things didn't work out for you! Did you miss a day's work too? I waited till 6:15, then I had to leave.

Are you sure there is no one parting out a car near you? Have you checked the classifieds/wrecking yards, that type of thing? I didn't have any trouble finding a used oil cooler. I actually found 2... the first guy didn't show up at the designated time, so I went elsewhere. The second guy turned out to be a cornucopia of Mercedes parts (been back many times since). He has a huge property, and something like 2 dozen Mercedes and Mercedes carcasses around. Since I'm a 'girl' he even removed the thing for me, and even offered to install it (which I foolishly declined). Anyway, I'm rambling, but there are lots of these types of cars around, and you don't have to have exactly the same hoses or oil cooler (the hoses we bought were from a different year, but they fit). If you're planning on bypassing the oil cooler, just buy a hose.

Good luck!

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Natalie

There is ONE 617 at a Junkyard about 20 miles away. Mon. the guy there was too look into it's cooler for me but never got around to it. .. of course he took off work today.

Used parts - http://www.car-part.com

Find a place near you, or have it FedEx'd overnight if necessary. I would NOT try to Rube Goldberg this fix. Fix it right the first time - a mistake could cost you a seized engine.

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Dave
Boise, ID
Check out my website photos, documents, and movies!

found it. it was Engatwork

Good site for metric fittings

Let's hear the case against the view that the oil cooler itself is a Rube Goldberg device. Why is it necessary? It introduces at least two obvious failure points in the lubrication system: the oil cooler itself and the hoses. There have been at least a couple of threads on this board which describe catastrophic engine destruction as a result of the failure of the oil cooler system.

How many other mfg's put oil coolers on their engines. I've never owned a vehicle with one, apart from Mercedes. If they are so important, why does Mercedes not put them on their commercial vehicles with the same engines even though they are likely to live a harder life in that application?

I suppose one answer could be that they didn't put AC in their commercial vehicles. But does operating AC increase oil temperatures that much?

Are there any volunteers for a test. One person disconnects the cooler and installs an oil temperature gauge. Another keeps the cooler and installs the gauge. Compare the termperatures.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

The OM617.95x and OM60x turbo engines have oil cooled pistons, with hollow channels inside the pistons that use the oil to carry heat away from the crown. Cooler oil keeps pistons from melting. Is it required under anything other than extreme conditions? I don't know. I'd be curious to see the results of the test you propose.

Now, about the oil cooler & cooler line failures. That is mostly on the W123 chassis. Almost every 123 turbo I know of has leaking lines or cooler. And it's a nasty job to fix. Mercedes did something to fix that in the late 80's, because the 124 oil coolers don't have this problem. I have never seen one yet that has lines or cooler than wasn't dusty and totally dry. But all the 123's seem to be seives. One more reason I dislike 123's and love 124's, but that's a separate thread!

__________________
Dave
Boise, ID
Check out my website photos, documents, and movies!

Kerry if all things were ordinary with my MB I would say your points are good for eliminating the cooler. Butttt alll things aint ordinary in my case. then never are.

On mine Im sure the oil cooler was neccissary as the rig and its previose owner made it's treck across the Libian desert. Though Im sure it was of no value when it trecked across Iceland.

For me.. a treck into the arrid lands of AZ, NM, CA or even desert's of South America is probably not ever to happen buttttt it's still a dream so I'll pretend it may really happen some day and put a cooler on it.

Do all those 508d's in Iran, Afghanistan, Morocco, Libya, India etc. have oil coolers on them? I doubt that they do. However, the point about oil cooled pistons on turbo engines is relevant since many of those 508's are non-turbo. But Mercedes put oil coolers on the 616 and 617 engines even when they didn't have turbos.

I may be off base, but an oil pan that held a few more quarts of oil would be a better option in my mind than an oil cooler.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

hmmmmmm any thoughts on this? I say this cause I already have an enlarged oil pan. To fit a 617A into a Unimog 404 the engine is rotated 13 degrees toward the passenger side. The PO then took the oil pan and had it reshaped bringing the bottom of it back to horizontal. This in effect enlared the depth of the pan. I wonder too if the oil pump on the bottom end of the engine is also modified to bring it to a horizontal position. Infact the modified oil pan may just be part of the kit... hmmmmm. I know the kit to install this set up in a mog is very spendy (2 grand or so).

I'll bet that the instructions in that pricey 617a installation kit include the following statement: "Plug the damn holes for the oil cooler lines and don't worry about them."

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

wellll.. one of my thoughts is this..... the PO is a professor of Nanotech engineering with one of the prestigious Technical institutes in Germany. I understand that tech. insitututes is Germany's version of a college of engineering. Nothing like our technical colleges where they teach u how to rebuild a lawnmower (and beyond)

He even redesigned the throw out bearing system; having new pieces designed and machined out in this thing to make it more efficient. Mog 404's like to eat clutches at times.

Another words he maybe a technical wizard or a technical goofball.

Not knowing which, I question if I should second guess why he kept the oil cooler.