Does anyone have a suggestion for getting the oil cooling lines off of the oil filter housing? I need to change the gasket for the housing, and those lines don't want to budge.

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Matt
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1995 E300 Diesel (Die Blau Frau)

When I removed the oil cooler lines the first time on my 1977 300D it required a lot of effort - much more than I initially thought it would take. Try some penetrating oil on the threads. If penetrating oil does not help and you are using a wrench that is the correct size then you may consider trying striking the wrench with a soft mallet to help loosen the nuts (what I ended up doing) - like using an impact wrench. If you are using a crescent wrench, then make sure the wrench is securely tighened on the nut before exerting any effort on it to avoid rounding the corners of the cooler line nut. Striking the crescent wrench with a soft mallet is OK if the wrench is tightened on the nut securely. Provided you do not object to hitting a wrench with a mallet.

Hope this helps.

Tom

Matt,

If your oil cooler lines have never been replaced, you may want to consider doing that once you get them loose. A MB factory rep once told me to replace mine about every 75,000 miles because if they rupture, your engine oil will be dumped on the highway in an instant and your engine ruined before you realize anything is wrong.

For what it's worth.

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Ted
1979 240D
165,000 miles

Thanks, Tom and Ted, for your replies.

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Matt
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1995 E300 Diesel (Die Blau Frau)

I suggest having the oil cooler lines rebuit if you are considering rebuilding them. Many heavy equipment supply/repair shops or hydraulic supply shops have the tools/supplies to rebuild hydraulic hoses (oil cooler, power steering, etc.). These repairs use components that are at least equal to or usually exceed MB OE components and usually cost a lot less. A couple of MB independent repair shops use rebuilt hydraulic lines - as well as AC lines done by AC supply/repair shops. I had both of my AC lines rebuilt for about $45 total and they have worked great - the new AC lines look a lot better than the old MB OE lines. The AC lines would have cost me about $200 each aftermarket and a lot more from MB.

Despite what the MB Rep said, I believe oil cooler lines should have a life span well beyond 75,000 miles. Also, unless your oil thermostat is open and sending oil to the oil cooler (because the oil has reached the temperature needed to open the thermostat), you may not lose oil if an oil cooler line fails. Also, you should have some indication of oil line failure before a major failure (like seeing leakage or bulging of the line). Also, your oil pressure gauge will drop to zero and hopefully you have enough time to shift to neutral and stop safely (recall, if the engine is shut off you will have no power steering or brakes - but you can steer and stop without the engine running with a lot of effort) - or you can immediately shut off the engine and muscle the car to a stop. Of importance is the fact that if you shut off the engine the steering lock will engage if the key is turned too far (likely in an emergency with adrenaline flowing) unless you can keep yourself under control and either not turn the key too far or turn it back to the unlocked position. Of course, without the engine running you will not have lights unless the key is turned back to the operating position. If you have total oil pressure failure and catch it the moment it occurs, then an emergency stop with the engine idling may not damage the engine - recall that when you change the oil it takes a while for the oil pressure to build up, the engine is using the oil that was left on the parts for protection. However, you must do an emergency stop as fast as you can if you leave the engine idling. This is a dicey situation to either leave the engine idling (with control over the car say in a situation where there is a lot of traffic and you need all the control you can get to avoid a major accident and/or physical harm to people) versus shutting off the engine immediately and then muscling the car to a stop remembering to turn the key so the steering lock is not engaged (saving the engine, but perhaps putting people at risk of injury and/or an accident).

Tom

Tom,

Your point about having the hoses rebuilt is well taken. I am about to have my air conditioning hoses rebuilt, but the possiblility of doing that on the other hoses had escaped me. Good idea.

You will also find me in agreement that the oil cooler hoses should have a longer life than 75,000 miles. When we see cars described in this forum with over 200,000 miles, I would almost bet that the majority had the original hoses still intact. I strongly suspect that, in general, very little preventive maintenance is dedicated to those hoses. I was just passing along what I had been told.

While avoiding engine damage in the event of a hose failure would be possible, a driver would virtually have to be looking at his oil gauge at the instant the oil pressure went to zero in order to avoid damage. And how many people drive while maintaining a constant vigil on the oil gauge? I did see a MB sitting on the side of a highway once with an oil trail stretching out behind it. Not certain, of course, but I guessed at what had happened. The rep stated that he knew of a number of engines that had been destroyed when hoses failed.

While I admit to not replacing my hoses at 75,000 mile intervals, I do inspect them from time to time and will replace them periodically (with rebuilt ones from now own). Better safe than sorry.

Thanks for your response.

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Ted
1979 240D
165,000 miles