My 1981 300SD with 240,000 plus miles overheated on the freeway a few minutes after I got on the freeway. Towed it home, found the oil had leaked out/been consumed. Refilled with oil, restarted and let it idle for about 30 minutes. Idled a bit noisier than usual, but seemed fine. Took it back out and it again overheated after about two miles on the freeway.

Car has never overheated previously in the year that I owned it. The thermostat is new in the last five thousand miles.

Did I cook the engine by running the oil down? Any other suggestions?

I'd check or replace the thermostat again. Sometimes the new ones are not very good.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

When was the last time you checked the oil and how low was it? (trying to determine the rate of consumption)

Overheated after 2 miles? I would have to ditto the thermostat suspicion. Either that or your water pump has failed completely. A severely clogged radiator might be another cause of the problem. Try the least expensive solution first.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Since the problem did not come on slowly over time by your description I would look for a failed item. Thermostat,cooling fan or fans,or head gasket, for example. You can find out how to check the water pump in the archives by hose pressure just in case the impellor let go. Hopefully you were not really right out of oil.

Ok, I replaced the thermostat with a new one, no luck. Car idled up to normal operating temp, and then proceeded to climb up to about 100 degrees before I shut it off.

Next, I removed the thermostat entirely. Overheated just the same.

When it overheats, the upper radiator hose is very hot. The lower radiator hose is cool. The middle and lower sections of the radiator are cool.

Dead water pump?

I would send the radiator to a shop and have it checked,replace water pump while its out,reinstall thermostat.Also check clutch fan,thats really quick to overheat,post your results

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

Before spending money on the radiator, you need to figure out how much damage was done by the low oil situation. Was it completely out of oil or just low? How much did you have to add to fill it up. If it was completely empty, you may have damaged the bearings enough to require major work and the investment in a radiator may not be worth if if you are not willing to repair the engine.

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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

What Kerry said is correct. Also every time you run the car and let it overheat, more damage is occuring. Just the fact that it idles louder now says the lack of oil has already caused some problems.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

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