Wife's Land Cruiser wouldn't turn over today so since my daughter's 84SD was parked nearby I pulled it alongside to jump the Cruiser. When I opened the hood I noticed there was oil all over the front of the engine of the SD. WTF? I peer around. The power steering belt had sawed a hole in the top oil cooler hose and oil had been squirting out when the thermostat opened. Yikes. Clearance was about 1/2" from hose to belt. Hose was new less than 2k miles on it. Not sure what was causing the belt to move closer to the hose enough to saw it thru but if my daughter had driven that car on the highway and got it warm enough to open up the oil cooler thermostat, that engine would have been toast in short order. Check your clearances and your top oil cooler hose.

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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

At least the damage wasn't any worse. I believe this is caused by collapsed motor mounts allowing the engine to sit lower than designed. Have definitely heard of the problem previously.

Check your motor mounts. If the one on that side of the engine has collapsed, the belt will cut the hose. When I got the 84 SD for my daughter, the hose was wrapped with electricians tape where the belt was rubbing a hole in the hose. Both motor mounts had collapsed, and it was just a matter of time before someone ran it out of oil also.

I got my 84TD because the motor mount had collapsed and cut a hole in the hose. Don't know how they caught it before they damaged the engine, but they didn't want to spend the money to fix it, so sold the car. While I really like the size of the 123 bodies, the 126 and 116 bodies sure have more room under the hood to work on the engines. Threading the oil cooler line on the TD was much harder than on the SD.

W.

How much clearance is there typically without collapsed motor mounts? The belt is 1/2" away from the hose when off and when idling. What circumstances cause the belt to move towards the hose?

__________________
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

I think the clearance normally is closer to an inch or two or so. That diesel engine rocks a lot, and those mounts are soft, so the engine can move around quite a lot.

When the engine mount collapses (they really don't last all that long...), the engine will sit lower, thereby reducing the clearance even further. The result of that is what you see under the hood now.

Replace the oil cooler hose (royal PITA job, unfortunately, but not actually complicated ) and replace the engine mount. You have to jack the engine off the mount to do the oil cooler hose, and so it's a great opportunity to do the engine mount as well. It's really just two more bolts at that point.

I had to do the same job on Betsie when I got her, as the oil cooler hose was showing deep rubbing marks (but hadn't cut all the way through just yet). I'd really suggest a helper, especially when feeding in the new hose as it's terrible to do by yourself.

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

How did you put that hose on? Did you replace the entire part all the way from filter to cooler? Or did you just replace the hose?

It is definitely old news at this point, but filling your engine mounts with Shore A 30 polyurethane rubber will prevent current poor quality mounts from collapsing.

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

Entire line was replaced.

__________________
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

On a bad motor mount or even a good one. The torque of the engine under load will pull the engine over a little more I suspect. I was just thinking that it might be possible to slide a short steel sleeve over the line and fix it in place. When installing a new hose. Then if a belt ever rubs the hose would more likely survive the event.


Because of current quality concerns at least any replacement motor mount should be filled as another poster suggested. Then it cannot collapse. Some of the aftermarket parts if not many are highly suspect now.


It was really fortunate this poster looked under the hood that day. There are also firms that rebuild motor mounts. Perhaps they equal original quality.

I was thinking some kind of hose protection would be appropriate in that location.

__________________
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

I was thinking of clamping a metal sleeve over the oil cooler hose closest to the fan. Should make an unignorable racket if the fan gets too close.

Sixto
83 300SD
98 E320 wagon

Agreed. I used loctite PL S30 Roof and Flashing caulk. its apparently urethane thats around that magic shore A30 number and very easy to find cheaply.

1 tube will do a set of mounts. it does take a long time to cure/dry. Mine took about 2-3 weeks, but its cheap.

I did them on my grey car and blue car.
Makes minimal difference in vibration but definitely stiffens the mounts up a lot!

__________________
1982 300D (w123, "Grey Car")
1982 300D (w123, "Blue Car")
2001 Ford F150 "Clifford" (The Big Red Truck)
1997 Dodge Ram 2500 12V Cummins
1996 Dodge Ram 2500 12V Cummins
Previous Vehicles:
1995 E300D, 1980 300SD, 1992 Buick Century, 2005 Saturn Ion

Thanks. I ordered some of the PMC 121-30 from Reynolds Advance Materials to fill the mounts.

__________________
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

I checked my daughter's 84 sd, and the belt is about 3/4" away from the hose. On my 84 TD, the hose is about 2" away.


D.

Thanks. I looked at my TD and it too is 2" away. Did it look to you as if the mounts on your SD are collapsed. Mine look pretty low.

__________________
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