A while back, after having switched to a generic synthetic oil, a drip developed from the base of my oil cooler. The MB mechanics looked at it, and said this had developed due to corrosion between aluminum and steel threading.
I've tried all sorts of gunk to seal the leak, but am learning that it's hard to keep oil from getting through.
A new oil cooler would cost me (so I'm told) about 200 bucks. This isn't a hell of a lot of money, but I find the thought of a "costly" repair to a cheaply-fixable problem objectionable.
Is there an option to replacing the working oil cooler just because it doesn't form a seal with the hose that attaches to it?
The drip isn't outrageous, but it isn't kosher, either.
Begging your pardon if this is a dumb question...Thanks.
I used a two part epoxy, Loc-Weld by Loctite (similar to JB Weld), to stop a leak on the A/C condensor or my 280GE. It was where copper and aluminum tubing came together, and could not be welded or soldered.
It lasted over 10 years without a leak; and freon and compressor oil are damned difficult to contain. The trick was in the preparation of the metal: Super clean and roughed up with a wire brush to give the epoxy something to grab hold of; and completely surround the repair to give it some extra strength by encapsulating it. As said, it lasted over 10 years without a leak.
Was "Hylomar HPF" among the sorts of gunk you tried? It's the best I've found for sealing things that need to hold oil in and yet need to be removed. It's also non-hardening (consistency of gel tooth paste) so you don't have to worry about excess getting into the oil.
I'd smear both halves of the mating parts of the flare with Hylomar, then coat the clamping and threaded surfaces of the nut as well.
If that fails, it's either renew the parts, or try Dutch's epoxy method to repair the corroded surfaces individually before re-fitting.
Be careful though. The oil cooler is none too strong and you can twist up the metal trying to over-tighten the flare nut.
Hi my cooler failed big time a few weeks ago just after an oil change and probably a cold morning start.
As the leak was high up it did adecorating job of the engine bay (see my earlier post re cooler) and sent at least a gallon over the engine bay and road.
Suggest that you remove the cooler ASAP and have a U bend or straight length of tube about 18" made up by a hydraulic pipe shop to eliminate the item for now. The thread size by the way is 22mm the ends will look different but seal with an internal O ring againt the male stubbs on the oil filter. The origional steel pipes can be removed easily without damage and will on inspection show corrosion.
Have a look on ebay plenty of more robust pipe type coolers fitted to thermostatic bypass valves.
Its noticable now much quicker the engine heats up for road work in local temperature -2c 10C winter conditions here.
Last time I had a leak on the oil cooler I fixed it by just wrapping ptfe tape around the thread and cranking the thing together again, I did later replace both metal feed and return pipes with flexible hydraulic hose made up for me by "Hose Doctor" I now modify all my diesel 300s as a matter of coarse if they leak.
....plenty of more robust pipe type coolers fitted to thermostatic bypass valves.
Its noticable now much quicker the engine heats up for road work in local temperature -2c 10C winter conditions here.....
The thermostatic valve is in the oil filter housing on the block where the cooler lines originate on the 280GE. Maybe yours has "gone south" (where it's warmer all the time?[:(]) if removal of the cooler results in quicker warm-ups. I think there's a testing procedure in the workshop manual.
The fittings in this case were not the issue, the core was. Strangly with the engine running no perceptable leak but on shut off you could hear the squirt!. At least I know the cooling fan works.
Regarding the oilfilter assembly cooler take offs didnt think that there would be an internal thermostat element. If so where is it in the housing (300gd).
My BMW RS 100 bike has one on its cooler circuit and is a wonderfully made little capsule affair.
On these diesel engines, the oil cooler is the most
likely thing to leave you stranded. I have been
running these engines for years with cooler removed.
Eight literes of oil in a 3 liter engine should
suffice in all but most extreme conditions.
If you remove cooler, you MUST remove thermostat
in filter housing,behind the large nut, take out
spring and piston,replace nut.
Block ports at filter hsng. I use ports for
oil pressure switch and temp. sender.
Warren
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