I broke the plastic radiator neck on my 300D yesterday. I don't know if it was original or not. I was thinking about replacing it anyway in the spring (it's been running a little warm in the summer). I can't complain too much, it broke about 2 miles from home after if tightened the clamp a little (I was 1200 miles from home last week, glad it didn't happen then). I was able to drive it home after patching the neck with some 1" copper pipe and JB Weld. The patch only lasted long enough to get me home, but it saved my from having it towed. I bought a new radiator today and I'll install it tomorrow morning. Not a big deal, just a PITA.

The moral is: Be careful tightening the hose clamps on those plastic radiator necks.

Is there some cosmic connection in Colorado? I tightened the upper hose on mine yesterday also. It was leaking after I removed it to install a lower radiator hose heater. I hope it is not about to follow suite.

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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

Were you tightening the clamp at the moment it broke?

If so, why?

I've been extra careful with the SD for that exact reason. I believe it's the original radiator.

It broke about 2 miles after I tightened it.

I've been looking for a slight coolant leak for a few months (maybe a 1/2 inch drop in the tank every couple of 1000 miles). On Sunday I heard/saw a little mist from the top hose connection while I was doing something else. I assumed/hoped it was just a loose clamp and tightened it a tad. The leak seemed to stop. I drove to the corner store and found it snapped off when I stopped and saw steam. I assume the small leak was from a crack in the plastic and I made it worse by tightening the clamp. It was probably due.

Just be careful, it doesn't take much to crush that old plastic.

Yikes, I was just commenting about this issue with hose clamps the other day.

German Hose Clamps and an Indy Shout Out

Here are some other Threads concerning broken necks.

Behr radiator, hose clamp torque?

Radiator Hose Neck Decides to break off 190E

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1983 123.133 California
- GreaseCar Veg System

yipes!

you were lucky it happened so close to home.

tom w

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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.

Man, before I heard of all these problems with the necks I was messing around with something ( can't remember what exactly) and undid the clamp on that piece but the hose stuck. I yanked it with all my strength and it finally popped off. I guess I'm lucky if didn't break.

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1985 CA 300D Turbo , 213K mi

I repaired mine using a PVC pipe connector, and JB Weld. I had to grind the OD of the PVC on one end to get it to fit into the radiator. I also had to build up the OD ( again using JB) on the hose end to fit the hose. I even added the little bump/rib on the hose end to keep the hose from flying off.
Its held for several hours so for. I will probably replace the radiator, but I want to delay that long as possible.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

That's basically what I did to get home, but I wouldn't trust it very far. It only takes about 1-1/2 hours to replace the radiator.

The mechanical part doesn't take much time, its all of the flush and reflush cycles.

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tgingrich
'83 300TD 282k
'83 300D 239k
'82 300SD 204k
DFW

I busted the one in my 420SEL. Fixed it with snadpaper, JB Weld, and some Copper pipe that fit snug inside.

So then I decided to reinforce the one on my SD. I know I had to use a different size tube, I believe I cut a fitting for the correct OD, sanded, and JB welded it in place. Cheap insurance.

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport

Well, mine's fixed now. I replaced the radiator this morning and all is well. I think main the trick is to not over-tighten the hose clamps.

If you use a radiator with a plastic neck, make sure you use one of the metal inserts in the neck.

240Joe

Reason #487 why we say we are driving the oldest car we can afford

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)