oil cooler line replacement - PeachParts Mercedes-Benz Forum

hangit · #1 03-22-2008, 04:26 PM

Just thought I would post a few tips on replacing the darn things since I just accomplished the job on my 83 300SD. I discovered that the upper hose had almost been sawed through by the PS belt when I was replacing all the drive belts. Don't ask me how.

1. Follow Diesel Giants advice on where to begin, jack up the car. (He has great pics on his site)
2. If you don't have a 27mm wrench, 1 1/16" wrench will fit.
3. Disconnect the vacuum lines near the oil filter housing, they will be in your way.
4. Drain your oil pan!!! (yes I did,

)
5. Have plenty of rags and a large drip pan correctly positioned.
6. Unbolt and remove the motor mounts, (replace them if needed) and engine shocks. At least remove them on the oil line side. Jack engine up. Trust me, it is a whole lot easier removing the oil cooler lines with these two items out of the way!

7. Unbolt the two clamps securing the lines. One is behind the PS pump, the other is on the block by the motor mount. Unscrew your oil cooler lines and remove. Upper comes out before lower.
8. I used antisieze compound on the threads before installing new lines. Lower goes in before upper. Line up and thread both ends of both lines before tightening to confirm they are place correctly. I then tightened the lower line on both ends, but before securing the upper line to the oil cooler I filled the cooler with oil using the 90 degree fitting from the old line mounted so it was pointing up.
9. Check fittings, replace motor mounts, engine shock. Replace vacuum lines. Refill oil pan. Start engine and check for leaks.

Hope this helps some one.

John

bgkast · #2 03-22-2008, 04:32 PM

Quote:

Originally Posted by hangit

I discovered that the upper hose had almost been sawed through by the PS belt when I was replacing all the drive belts. Don't ask me how.

Saggy motor mounts, that's how. Hopefully you replaced them while you had it apart.

hangit · #3 03-22-2008, 04:42 PM

Quote:

Originally Posted by bgkast

Saggy motor mounts, that's how. Hopefully you replaced them while you had it apart.

They didn't look soft or saggy, but they were replaced.

John

barry123400 · #4 03-22-2008, 10:19 PM

The oil line sawing might have happened before the engine mounts were changed the last time. Maybe he missed it at the time or figured the partially sawn line was okay.

TX76513 · #5 04-04-2008, 02:43 PM

The old one came out fine - now it's like one of those nail puzzles you find in a bar. Jeeze what the secret to threading these things back through?

Chad300tdt · #6 04-04-2008, 02:53 PM

I'll be doing mine tomorrow. I think it might be easier for me since I removed the mount arm from the block. The bolt holding the mount to the arm was stripped so I had to remove the arm too. I think it might be a benefit on the oil cooler line job though. I'll know for sure tomorrow.

Nice post John.

hangit · #7 04-04-2008, 10:39 PM

Quote:

Originally Posted by TX76513

Jeeze what the secret to threading these things back through?

Unscrew your oil cooler lines and remove. Upper comes out before lower.

That means lower line goes in before the upper. Don't secure them until both have been properly positioned. Great puzzle right?

John

Chad300tdt · #8 04-10-2008, 10:03 AM

Other things I found useful during my repair:

7/8" wrench to support fitting on the oil cooler

My fittings were frozen on the oil filter housing so I cut the lines close to the fitting with a hack saw blade wrapped with a shoprag for a handle. I sprayed the blade with penetrating oil to lube it. Then I used a socket with a ratchet to remove the fittings from the housing. I used my vice and the wrench to separate them and put the coupler fittings back in the housing with blue thread lock.

Having the engine mount arm removed allowed me to take the upper hose out the top and the lower hose out the bottom in about 5 minutes. I put the new ones back the same way and then put the mount arm back on. I can see how if the mount arm was in there, it would be a lot more difficult.

Thanks for this thread John, it was helpful.

SD Blue · #9 04-10-2008, 10:55 AM

Wow! I've never solved one of those nail puzzles but didn't have much trouble at all with the oil cooler lines. (Not bragging, just puzzled by all the problems folks are having.) All I did is remove the motor mount and jack the engine about 1" for a little extra clearance to reinstall the clamp.

Here are a couple of things I found that helped with removing the line from the filter housing. Take an inexpensive box end 1 1/16" and use a dremel tool to cut and make it a flare nut style wrench. Double wrench with a 42mm line wrench(thin) on the nipple fitting. Putting the wrenches in close enough proximity to use hand grip pressure to break them loose saves on rapped knuckles.

bigfredb · #10 04-10-2008, 12:17 PM

Had the same Oil cooler line issue a few months back. Replaced the hoses, mounts and shocks.

I also wrapped the upper oil cooler line with an aluminum can (edges folded over, zipped tied onto the hose) and zip tied the upper hose to the lower one. I did this to maximize the space between the hose and the belt as well as give an extra measure of hose protection.

Probably overkill, but replacing those lines was an over-b*$ch.