Mybad...I didn't think to check his signature and didn't see that it was a 240.

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Never a dull moment at Berry Hill Farm.

Have you taken the radiator cap off and visibly checked the flow when the engine is warm?

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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

No, however, when the problem cropped again after the radiator was replaced, the lower hose was stone cold after driving 30 miles. I replaced the thermostat at work that day, and the lower hose was still cold after driving it home from work that night. After the water pump, and rad cap replacement, the lower hose now feels very close to the same temp as the upper one.

The first time that this cropped up, we found the radiator clogged. Problem went away completely for a while. Then it came back during a drive to work. The T-stat did not solve that problem, and I had to be very careful getting home. The water pump, coolant flush, and rad cap replacement solved the problem for a while again. The coolant level has not changed, and has not picked up any new soot or oil.

I wonder if a radiator and associated parts for a 300D Turbo model would fit in there? The extra radiator capacity would probably solve the overheating problem. I don't know where the air cleaner sits on the Euro 240D, whether or not there would be room for the degassing tank.

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

I think Leathermang is right on if I try and run my SD up a certain pass here in forth temp goes up fast no matter what the outside temp is. however if I go up the pass in third the gauge stays even as I am not lugging the engine.........
William Rogers........

If I were pulling hills, then I would agree. Problem is that I'm heating up on flat level ground, an area where the car should be able to cruise along in 5th without any issues. I have no problem with downshifting to accelerate even at highway speeds.

Palangi, I believe that the 240D and 300D radiators are the same capacity. The difference in coolant capacity between the two is quite small (around a pint IIRC), basically enough to account for the extra cylinder.

I'm going to try drilling the hole in the T-stat @ the bypass hose when I get back in town. I'm also going to try rebuilding the injectors to see if I can cure the constant smoke issue despite them passing the bench test.

Diesel Power

Below is a copy of a .correspondence. the first is from me and the reply is from the guy that turned me on to this by pass flap thing. You might have the erosion problem he talks about.

Bruce

Well it sure would interesting to try a "NEW" and I mean new T stat housing. That would prove your theory. Actually that engine is now in a car I sold to a friend and it was well over a year ago I talked to you about this. It was running a little warm for no reason that I could find. It was flushed, good radiator, the works, MB coolant etc, etc.. The "80" engine I rebuilt (3K now) is running at 90C and will run a taste over that when on the highway.


Date: Sat, 08 Nov 2003 13:01:46 -0800
Steve,

I have two housings that are eroded and there is no absolute way to
determine their condition except by measuring the valve seat depth and
runout with a depth gauge. I have noticed that both of the bad housings
have dark discolored areas adjacent to the valve seat surface which might be
metal particles flushed from the wear surfaces. I suspect that the wear is
caused by two factors: electrolysis, and metal-to-metal abrasion between the
thermostat valve and the housing seat. The seat must be perfectly flat to
seal the bypass, and at the correct depth corresponding to the thermostat
travel. If not, hot coolant will leak past the bypass valve back into the
engine block instead of flowing through the radiator. The hole in the
thermostat valve makes the thermostat push the bypass valve farther into the
valve seat, hence sealing off the bypass better and forcing more coolant
through the radiator.

Bruce

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

I think the radiator of the N/A 300D is only slightly bigger than the 240D, however, I think the capacity on the turbo model is more. The turbo model's cooling system certainly carries more coolant because of the expansion tank, although that portion doesn't really circulate much.
I know on 115 240D's, it was quite common to upgrade to the 300D radiator for extra cooling capacity. My 115 240D doesn't seem to run hot at any particular speed, however it does heat up a bit on a long uphill grade, even in cool weather. If the radiator ever pops on that car, I will put in a 300D radiator, but, for the moment, it seems like there is no need.

edit: FWIW, I just looked up the capacities. 240D carries 10.5 quarts, N/A 300D carries 11.7 quarts, Turbo 300D carries 13.2 quarts. So the capacity of the N/A 300D is only about 10% more, and not all of it is radiator, of course.

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

Thanx Stevo. I really wish I had time to tear into the 240 tonight. I want to visualize what you're explaining. The eroded bypass valve makes sense with all of the other items being verified and accounted for.

Off now to run a search to see if anybody's ever posted a pic........

If you really want to experiment remove the thermostat completely. On the vehicles that I have seen this done you hardly ever get above 80dC.

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Jim

Hi This is my first post. I don't want to stir up any more problems. Do you know your temp. gage is reading correctly? I spent a conciderable amount of time trying to trouble shoot a hot running MG only to find out it was actually a faulty temp gage. Just a thought. Good luck

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Kevin
82 300D

Yes, the guage works correctly up to 105c. After that, the guage jumps around between that and 115c. I intend to replace the guage pack with a new one after the higher priorities are done as it's accurate enough to work with for now.

Any luck with that bypass valve yet, or haven't you had time to tear into it yet?
~D.J.~

Nope, I spent last night getting ready to leave town after work this afternoon. My first chance to look at the 240D will be Thursday after I finish running some critical errands - if I get back by Wednesday evening as planned, and the weather holds (they're already calling for rain).

This may sound silly but how do you know the guage is working correctly at all? If it came out of a car that already overheated I would not trust it. It should be running at about 85C for it's normal temperature. It could be that it's reading is off and you dont really have an actual overheating problem at all. I would certainly want to remove it and check it independently against another thermometer before proceding with more complicated stuff.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S