Our 240D W123 had an oil cooler line go bad and lost 5 quarts or more.
Did not know of the problem until draining for an oil change. 2 1/2 quarts drained out.
Therefore a check of the main bearings is in order.
Any advice on how to proceed?

Have removed the oil cooler lines. Was able to find a factory replacement for the upper but not for the lower. The dealer no longer stocks the lines.
NAPA crimped a new high pressure hose on the old metal with steel clamps using a hand operated crimp tool made for a/c work. Looks solid but many people doubt that it will hold.

Any opinions will be greatly appreciated.

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My best advice:

Install the lines.
Fill the engine with oil.
Run the engine with special attention over the next 1000 miles for oil pressure, noise, and power.

At worst you waste some oil.
At best there is no damage.

.

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Well--IF you really are determined to have a look at the bearings, its Normally nos.1 big-end that suffers first.--So this is the easiest to access after removing the bottom steel-pan and maybe the oil-pump for easier access....
--This is because its the 'last' in the oil-supply line and will be the first to lose pressure and suffer.

IF the nos 1 big-end is good, its a pretty good assumption that the rest will be fine.
--What is the oil-pressure At Idle--with a fully-hot engine?--This is another indicator of condition

As WHunter suggests though--is the easiest way--The outcome whichever you do will be the same....

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Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

If you had 2.5 quarts in the pan I agree with Roy, don't fool around opening up the engine. It is not likely to have suffered any significant damage. I would not risk the investigation. Its much more likely you would cause damage investigating than any damage having occurred so far, IMHO.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Anyone ever retro fit a low oil warning system into these engines?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Thank you all for your response.

What is your opinions on the oil hose?

Good question on the low oil warning system.

If the crimp ferrule and hose used is rated for oil at the temps and pressure needed it should be fine IMO. Looking at the red hose, the crimp is unusual in that it is lengthwise relative to the hose rather than circumference wise. Don't know if it matters but I would feel more comfortable if the ferrule is crimped like the black hose.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

If your Engine has a small separate Oil Pan I would drop that and look for Metal Fragments.
Next place to look is the Oil Filter and Housing.

He did not say what year 240D He had. It if has a Aluminum top cap on the Oil Filter Housing and there is room above to close the Hood He could do as I did in the below Thread.
But, as some pointed out if you are on the Freeway and you loose Oil Pressure the pressure has to drop a long way to trip the Low Oil Pressure Alarm at about 7 psi. That is not supposed to be enough to lube the Engine at high speeds. But, it is better than no warning at all.

Low oil pressure alarm for 617.952
Low oil pressure alarm for 617.952 - PeachParts Mercedes ShopForum

In a low Oil Pressure situation I think the Rod Bearings would go out first.

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84 300D, 82 Volvo 244Gl Diesel

There is not any evidence of metal shavings in the oil filter or housing or the oil pan.

I miss spoke calling it the main bearing. It is the rod bearings that I had intended to inspect.

What possible harm can be done by the inspection process?

Is their a simple low oil warning system? (Other than the dip stick)

The one I posted is the simplest. There is at least 3 long threads on the Low Oil Pressure Alarm.
Some of our other Members were working on something but I don't know if they ever finished it.

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84 300D, 82 Volvo 244Gl Diesel

I have seen ideas on this subject in the past but do not recall seeing a simple low level light.

Your device is a more accurate solution than the stock pressure gauge.
It should give a broader range of the actual pressure than the one on the dash that gives us 3 bars or about half of the actual oil pressure.
And it seems illogical for the stock gauge to show full pressure when there is in fact zero pressure.

In regards to to ferrule crimp: I went to CarQuest and they said that the metal portion of the line would not fit into their machine. The first three guys at NAPA said the same thing and that their machine was the same as CarQuest and had the same fittings. But the next man that saw the hose, took it immediately to the back, cut off the old ferrules saw that the length of the metal line was long enough and had a flare at the end so that the high pressure line and steel ferrule that is used for air conditioning systems would work. He used a hand operated crimping machine and carefully applied pressure several times over many minuets and connection seems very solid.
$8.50 total
The factory upper hose was $127.80
I will report back after 1,000 miles.
A Mercedes shop in the next town uses this method exclusively for years. The operator of the machine is the key.
Ultimately it was the crimp that failed on the lower old oil cooler line that caused the biggest oil lose. The oil was actually misting out and was visible on top of the hood and cowl in front of the windshield. Could not have seen it but for the fact that the car is white.
I hope that this one last half as long as the old one.

I must be very unusually or very anal...maybe its my Virgo traits....

But I always check my oil every few days, I always take the time to inspect my engine for new leaks, look under the front end at the suspension.....check hoses and every so often look under the rear end....I know my car is 30 years old and as much as I hate finding things wrong..i always want to know what is wrong....I have a mental list of asap when I get funds to fix and things to fix in the future..

As regards to the oil lines, I believe both can be had online for 150$....

It has also been mentioned a lot that the proper psi hose and two hose clamps at each end can be used to replace the oil cooler rubber line.

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One of our Members used an A/C crimping Tool to make His Oil Cooler Hoses and even used the A/C Hose on it. For some reason I did not save the Threads to My notes:
I am guessing if someone picked one of the words like Mastercool and searched they could find the thread.

"Galaxy® 4890 SLE A/C Refrigerant Hose A/C hose (used #12 Hose= 5/8“)
Mastercool 71550 Manual Basic AC Hose Crimper kit MA71550 $146"

I guess I am even a bigger Thrill Seeker.
When I first tried to replace My Oil Cooler Hoses with only Hose and Clamps I had to take one old Hose apart to get the size.
I ordered 1/2" Hose that ended up being too tight to fit.

The Mercedes was the only Car I had to get to work in and one Hose was taken apart.
It would be as long as 2 weeks till the 5/8" ID Hose I ordered would arrive.

I bought some extremely heavy Duty 5/8 ID Heater Hose and used that with Hose Clamps till the correct Hose came.
I only drove to places I absolutely needed to go to and tried to keep an Eye on the Oil Pressure Gauge till I got the Right Hose.
I also stayed off of the Freeway.
I had no issues with the Heater Hose use for that short time. But, not recommended

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84 300D, 82 Volvo 244Gl Diesel