Ok, I've tried all of the above. All the are bubbles are out and still no dice. It looks like I have the dreaded cracked head based on other research. So, the car is up for sale as a whole to start with. Thanks for all the good advice.

http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/282551-1987-300d-whole-car-parts-ct-%24800.html#post2521938

Sorry it has gotten you to this point, but I clearly understand your frustration.

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

I have been driving my 240D without a thermostat almost 10 years.

About 10 years ago I bought a complete engine from the dealer and replaced my old motor on my 240D 77. Shortly thereafter a big chunk of rust that was stuck somewhere in the remanufactured motor came loose and filled the cooling system, the coolant was dark brown in color. At any rate the mechanic suggested that I replace the radiator, change the thermostat and clean up the mess. It was all done except that the new thermostat refused to open no matter what, they burped and did all the tricks, nothing helped, I finally told the shop to remove the thermostat, it all started to work fine without one.

It has been almost ten years without a thermostat and since I live in Houston where summers last 9 months not having a thermostat keeps the engine a bit cooler. In the winters I put a little cardboard in front of the radiator to help with the heat, everything works just fine.

Vahe

A whole parts car???

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Chris Brown
"OC", So-Cal
1979 240D, 122K, 4spd, Colorado Biege w/Tobacco, Pwr Roof, AC, Cruise, Becker Corona - SOLD
Past Benzos: 71 250 • 83 240D • 84 190E • 04 C240 • 11 GLK350 • 13 c250 Coupe
http://www.peachparts.com/shopforum/...ine=1276896801

Was there a "smoking gun" that brought you to this conclusion? Since joining this forum, it seems like there have been several threads with engines getting hot and virtually every part associated with cooling is replaced, yet the problem goes unsolved. If I had the money, I'd buy it and replace the head, BECAUSE NOW, I JUST WANNA KNOW!!!

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-Louis

'87 300D Anthracite

Check out this thread:

http://www.mbworld.org/forums/e-class-w124/352160-1987-300d-turbo-overheating.html

It sounds like a pressure test wouldn't even give conclusive evidence because the crack may not open up until the car gets hot.

Basically, by the elimination of all other factors I've finally decided that this is the most likely given problems these heads have. My brother owned the car previously and when the water pump failed, the car overheated. That's probably when the head cracked.

That would be, in many cases, because no problem existed in the first place. Except that too many folks have the very mistaken notion that their engines should run at 80 degrees C while sitting in stop-and-go traffic on a 100 degree F day with the a/c running.

OK, backing up in the thread a bit, just one more question...would this happen to be a Behr radiator?

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-Louis

'87 300D Anthracite

You might want to study up on the operation of a bypass thermostat. Then you might understand the reduced flow to the radiator. (Operating without a bypass thermostat is a totally different concept than operating without a conventional thermostat.)

yes. Behr.

I'll look into the thermostat issue but right now it seems like i'm getting plenty of flow. The radiator is hot. It took a lot of bleeding of air out of the system to finally get this. What happens now is that I can drive it around indefinitely at low load situations but as soon as I take it up a steep hill or on the highway it hits 90 degrees or so and then shoots straight up to 120.

The reason I ask is that all the recent posts about engines getting too hot have all included the replacement of the radiator with Behr ones because they are OEM. One poster even said the overheating got WORSE after the replacement IIRC.
So, since the neck on my radiator recently broke off, I have ordered another. I considered a Behr, but of the places that carried them I checked, they seemed somewhat generic. The description would say something along the lines of "W124 diesels, all models" whereas the description for the Nissens stated specifically "OM603 equipped W124 models" with 3 row core. Since the price was about the same, I opted for the Nissens since everybody else had tried the Behr units and the Nissens was so specific. It may have nothing to do with your problem, but I'm tempted to bring you my new one when it arrives for you to try to see if it helps, if you wanted to do something like that.

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-Louis

'87 300D Anthracite