I am looking for opinions on next 100k mile running costs

2 well sorted cars
99 e300td versus e320cdi

what will cost me more to maintain (using good honest indy to service-most things)

Both cars are in low 100,000 miles- and nicely running/sorted now.

looking for advice- if I only keep one

thx

My guess is the 99 will cost more. Plus, since you live in Chicago, rust will eventually devour the 99.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Yup, living in Chicago will demolish a W210 with rust.

I had a W210 wagon for 5.5 years and only drove it about 40k miles, and rust still demolished it. Meanwhile my 2005+ vehicles, no rust at all....still going strong.

If the rust factor was taken out of the mix, the W210 miiight win, but I'd doubt it.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I wouldn't drive the w210 in winter-
point taken

would drive april- nov
and hope to eventually - retire somewhere warm

They definitely had a corrosion problem in the W210 chassis. This was completely and thoroughly solved in the W211 and later (so long as the body panels are undamaged).

Also another thing to consider, be sure you have a way to diagnose the electronic systems on these cars. If something goes wrong (and it will at this age) you definitely need a decent diagnosis machine.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Any suggestions on good OBD for this car?
would be nice if it works well on e320cdi I own-- too

thx

Many here like the Foxwell NT530 (updated version of the NT525 which gets mentioned here more) for W210 cars with the 38pin connector. I don't see why it would not work for newer cars as well (you just remove the extra connector).
https://www.foxwelltool.com/wholesale/foxwell-nt520-pro-for-benz-with-benz-38-pin-cable.html

They cost $200, but I no longer need mine. My w210 wagon was unfortunately totalled recently and we decided to get a used electric car as well. I would sell mine shipped for $150. It is in perfect condition and was only used twice.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).