I got on the highway today after a few different trips with the 82 300sd todayand about 15-20 minutes into my drive (just got on the highway) I noticed something -sounded- different. I then realized my RPMs were higher than they were this morning (I thought they were high then - 3000 rpm @ 60mph. This time it was 4000-4500 RPM at 60-65mph). I kept driving, caucious that something was going wrong... I noticed then that the engine was beginning to overheat! I pulled over after a minute of debate and got the car towed the rest of the way home.

What happened? Did I lose my ability to shift into a higher gear?

I tried searching for this and came across someone with overheating issues and they said to check the oil pressure guage. Mine ALWAYS stays on 3. Is it broken??? And if it is, maybe this is the issue? Would that cause the RPMs to be so high?

Thank so much! This car has been a nighmare this first month I've owned it..

Edited to add:
Not sure if this means anything besides that it's rear wheel drive... when I get going sometimes (when I first start the car on a small incline or wet day) I get a really high pitched squeeking. Are these just my tires? It sounds like it's under the hood. Not sure if it's related, I heard some people's radiator pumps or something sometimes cause this sound.

It's possible that the transmission hadn't shifted into final gear and you were driving in 3rd the entire time. Overheating was probably from the excessive revving. How the fluid level in the transmission?

Does the oil pressure go lower than 3 when at idle and peg when you go past say, 1500 rpm?

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Allen Kroliczek
Oak Grove Autosport | Oak Grove Autosport
01 G500, 82 300TD, quite a few more.....

Was the transmission in 'S' or 'D'?

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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

On the first problem, it may be that you had it in S instead of D. Or you may have lost 4th gear, or you may have a slipping transmission. Drive it again and count the shifts. There should be three.

On the second problem, it sounds like you may have a loose belt. If it's the one that drives the fan and water pump, this would contribute to overheating.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.