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2002 C240 & 2006 E-350 4MATIC
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12 Posts
Discussion Starter #1
After many steps to eliminate possible root causes, I am having continued overheating issues with my 1987 W124.

Symptoms: After completing work, drove around town and on several highway jaunts without incident, however on a recent drive home temp gauge spiked. Water is gone in tank, no visible hose leaks or spray. Refill, drive a bit, problem repeats. This is essentially the same issues that spurred the below work.

Work completed:

1. Thermo
2. Water Pump
3. Fan Clutch
3. Radiator
4. Overflow Tank & Cap

The strange thing is that after the work was completed (car sat week during repair) I was able to drive without incident. Only after a lot of driving, and specifically going on long uphill grades with the engine in a pull did the problem repeat.

There is no coolant in the oil visible and no smoke from the tail.

The only other concerns I know of are the normal vacuum issues these things are known for...hard shift etc. result.

Any thoughts as to next steps...I feel too deep to give up on her now as she is mint body/interior.

Any feedback appreciated.
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,761 Posts
For my money, I'd change the thermostat. If you still have your old one, try it. I understand that you've replaced it with a new one, but I have seen new, out of the box units that are bad.

What brand thermostat did you purchase/use?

Jayare

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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17,408 Posts
Make sure that the t-stat is installed correctly with the ball bearing on the t-stat at the highest point.

I also recommend changing all 3 temp sender units.

Are you using genuine MB or OEM/OES parts???

Finally, make sure that the radiator cap is rated at 1.4 bar.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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17,408 Posts
IR thermometer will answer lot of such questions in just seconds.
Automotive cooling systems use the pressure cooker method to keep from overheating. That means, without holding proper pressure, it WILL overheat no matter how new all the other bits might be.

Raw temp is only part of the answer. Example, if the expansion tank has a hairlline crack in it then the system will never hold full pressure which will result in a high temp reading on the dash when the engine is under load.
 

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95 E300, 91 300TE, 84 190D
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784 Posts
headgasket failing

Cooling system sound, no leaks or drips, but overheating and loosing coolant. Isn't that the first sign of a failing headgasket? Coolant can be lost without the tell tale white exhaust.

If one were to let that car idle in park for a while, would coolant droplets come out of the exhaust?
 
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