I just replaced the tank in June, Now the tank has a dome on top ! Is this because of a motor/Rad issue? or They just dont make them like they use to ? 300 sd w/230k on the clock ! Thanks,J

Did you replace the cap at the same time? What pressure is the cap rated at?

Yes, I replaced the cap ! Roy sold it to me . I looked at it and the only thing I could make out is that 1 of the sides says 140 the rest is German writting on it ! I started the car and looked in side I did not see any air!

it should say 120 on it. 140=1.4bar and 120=1.2 bar... I'm not sure how much that .2bar (2.9psi) difference made.

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1985 300D Mango Green with 16" Pentas, Vogtland springs, Euros/ clear corners, 234k, lots to come soon....

Actaully between 140 and 120, it is 20 psi difference

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'85 300D Turbo - CA Version

..........how about we say 3 psi.........20 psi might blow the tank apart.

What is the danger of getting a 140-rated cap instead of a 120-rated one, if any?

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http://farm8.staticflickr.com/7271/7...144c3fc1dc.jpg

No danger whatsoever. It provides a bit more margin against boiling.

The expansion tank on my 124 says to only use a 140 cap. The tank is very hard plastic.

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Dale

http://i52.photobucket.com/albums/g1...MG_2277sig.jpg

1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

I apologize for being such a smarta$$. That being said, what does the radiator cap numbers 120 and 140 stands for? Is it boiling point in Celcius?

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'85 300D Turbo - CA Version

Millibars pressure. 100millibars = 1 bar pressure. 1bar = 14.5psi

Ok , Now what would cause my tank to enlarge ? the top has a slight dome shape . No bubbles in tank ! thanks, J

Not to be too picky, but 1000 millibars = 1 bar and 100 centibars = 1 bar. So the cap is actually in centibars, not millibars.

Boiling point in Celcius is 100.
I've had the expansion tank, in the 85 300D I used to own, expand and crack from too much pressure. I guess it was too old and brittle. I might have had it overfilled then too. So much for an "expansion tank".

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

You are right. Dang decimal point... That's what the schools get for trying to teach metrics and american measurements at the same time.