I have over 376,000 miles on my 85 wagon. It runs great and doesn't burn oil. How many more miles do you think I have before major work to be done???

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85 300TDT 456,000 orig. miles

If she runs great and doesn't burn any oil and has good compression, I'd say keep everything maintained properly (fluids changed, filters, valves, etc) and she'll last indefinitely.

Congratulations!

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

Very hard to say when, it seems like many of these will almost definetly last 200k or a little more but they then go in the grey area where it all depends on how the car was taken care of throughout its life. Yours appears to be well taken care of in the past, if you take good care of it it'll take good care of you and your checkbook.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

If it ain't broke, don't fix it and don't worry about it, just take care of it and enjoy. Your obviously doing things right.

Good luck,
Change oil hot and change oil often,

Check the chain for stretch - at that mileage if you are still on the original chain you are taking risks without regualr checks. Check the tensioner while in there.

I would say that if it's still on the original chain at that mileage it should be replaced... they don't last forever. I bet it's already been replaced though or it would have some serious stretch and timing would be off some. I wouldn't worry about anything else if it's running good.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

chain was replaced at 303,000. I guess I'll need to change it again at 400K?

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85 300TDT 456,000 orig. miles

I would think more like 500k for the next chain. From what I've read most people replace them every 150-200k... just to be safe... so with proper oil changes they should last longer.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Was the chain tensioner also changed? That's as important as the chain. My 300SD has 80k on its second chain (120k on the first) and it's only one degree stretched - many say replace at 4-5 degrees. I changed the tensioner when I changed the chain.

I don't believe it was changed. I'm still not quite sure how to determine how may degrees it's off. I plan on changing it again at around 400k

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85 300TDT 456,000 orig. miles