300SE-89 High RPM
 

Thats about right for that car. they had to gear down the car quite a bit to get that m103 engine to pull that big body.

Nice find BTW, can you post some pictures?

Thank you
 

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Welcome to the forum!

That is a common complaint on that engine, especially with an automatic. You have a low mileage car, but it might help to replace the motor mounts and you might get rid of some of the buzz. A 4000 rpm you are running at about 70% of redline which is a good place to be for efficiency. It is a pretty speedy engine and really does not pull well until over 3000 rpms. I have a 5 speed manual on a 300E, and at highway speeds I am looking for another gear also.

That definitely is a good and rare find. Hope you figure out the workings of this site soon and welcome to the forum.
I was always puzzled at the high rpms on my 88 300 SE also. Just wondering if that contributed to the "cam towers pulling loose" problem w/the M103.......

THANK YOU ALL FOR TAKING THE TIME TO COMMENT. GIVE ME A FEW DAYS TO LEARN HOW TO NAVIGATE THE SITE AND I'LL SHARE FEEDBACK.
BEST WISHES TO ALL.
JARR56

welcome to the best of forums. looking forward for your 300se pics.

300se /89

My 1990 300SE engine revs are 3800 at 80 MPH and 4300 at 90. However, it will, and has, run like that for hours on end. I've gotten used to it. The engine seems really at home in that range.

I thought that the cam tower problem was on the 86 and 87 early production models and then MB fixed that problem in mid 87. Haven't heard much of the problem on 1988/89 models. Hope that is correct as I have an 89 engine in my 86 for that very reason.

Welcome to the forum and as a fellow 89 300SE owner you will get used to the RPM's. My 300SE has 155K on it so yours is just broken in! One thing that is nice about the higher RPM's is that the car will pull hills on the highway better. There will not be any of that shifting/gear hunting nonsense that I get on my other overdrive equipped cars. I will get 20+ MPG cruising at 60ish. Enjoy and I look forward to seeing your car! She has spent a lot of time just sitting.

3.46:1 is the rear ratio, so with a 1:1 final gear that is the RPM you receive.

If you are missing your under body shields/sound panels, try to find them. They really help keep the buzz noise down to a minimum at higher speeds.

I have a 1988 300SE WITH THE (#5) CAM TOWER BOLTS STRIPPED OUT OF THE HEAD at about 130,000 miles. Evidently they (MB) skipped this one. Not trying to alarm anyone, just throwin' that out there. I was only going about 65 mph when it happened.......

I think all 86-89 M103's had issues with rocker,cam hardness as well as the cam tower issue.