I have a '86 300E and I quite dislike how high the RPMs are when on the freeway.. I normally like to cruise at around 130k or 140k but even there the RPMS are getting unrealisticly high, and I refuse to go higher because I feel for my poor car. =P Is this normal? Is there anything that can be done to remedy this? My old '87 automatic Honda Accord seemed to be lower revving and it was a little four cylinder 2 liter!

Its normal. It bothers a lot of people at first, but I like a quick spinning engine. No its not as relaxed as a Town Car, but there are advantages. You dont have to shift to pass as often and your engine is really turning the wheels at 75 mph, rather than just coasting along at 1,300rpm. In addition, I enjoy the sound of this engine at 3500rpm. It gives me the feeling of control also as there is better throttle response. Engine is not downshifting everytime I speed up. Makes me pay attention, for some reason. Hope this helps, in some way.

Mike

Like already said it's pretty normal the 300E is no torque monstor :p

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89 190E

Thank you for your responses.. I guess my only question is, am I doing damage to it by revving it high? For example, how fast can I cruise at before I'm taking life off my engine faster than normal? is 4,500 rpm, for example, not a good idea or perfectly acceptable with the engine design?

the M103 is a peaky engine, coming alive past 3500rpm or so. As such, the gearing of your car is designed to take advantage of that characteristic.

if you search through the forums, you will find out that the thing is designed to run all day near redline, being designed for the autobahn. And that it is perfectly happy doing so.

one thing you can probably do is to change your rear end ratio, but you must do the following also:
* find a way for the car to permanently start in first
* find a way to correct the speedo reading (i believe that there is an electrical device to do this)

You could put larger tyres on then re-calibrate the speedo to read higher.

This will be the cheapest option, you'll get a smoother ride too.......

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Paul Gibbons
'93 320CE
'73 Jensen Interceptor (Resting)
Giant Full Sus Mountain Bike

What's a good gear ratio to run with a 190E. I'll be running 18's this summer it might be a good idea for me to get new gears.

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89 190E

If your engine is well maintained and in good operating condition, I do not believe that you are doing any harm or over-stressing your engine at 4500 rpm. Like one of the previous posts said, you can run you engine at redline all day with no problems.

Make sure that your timing chain isn't due for replacing and run a high quality oil like Mobil synthetic and you'll be o.k.

I occasionally redline my 300E and the only precaution is to make sure you have good clean trans fluid and a 20W50 oil. After I get my head gasket changed, I will use Mobil 1 15w50 and really take it east of 4000 rpm. Make sure the air filter is clean because you don't want to have a "choked engine." Beware though, there has been some tsb on engine overrev damage.

Ok, let me get this straight, the higher you rev your engine, the thicker oil you want? Why do you reccommend 20-50, isn't that for either leaking or very low revving engines? I was using regular castrol 10 - 40, should I be changing that? I have heard much talk of the Mobil 1 synthetic, is that definitely worth the money? Extra money on oil to save money down the road is definitely my idea of wisdom.. Lemme know! Thanks!

Also, as for a filter.. Any things I should note? Is there a better or worse filter or should I just a 'mercedes' filter? I was reading anouther intresting thread about trying to force more air into it... Would be cool, but right now I think I'd better get it running 'right'.. ;-)

Opps, one more question.. What's this about "'tsb' on engine overrev damage?" Could someone elighten me to what was just said? =Þ

technical service bulletin as far as I know. check on alldata.com for information on issues regarding yoru model car and year.

Thicker oil like 20w50 is not for leaky engines and such. I have always used 20w50 in my cars but I live in southern california, so its always fairly warm/hot down here.

My mercedes mechanic uses 20w50 as well if I have him change my oil.

As far as I know in colder climates you want a thinner oil so that it will lubricate everything sooner. in the cold thicker oil will take longer to warm up and lubricate the engine.

Alon

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'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon

It's not a simple correlation but originally my car was in Wisconsin and the dealer still poured Castrol 20W50. It depends mostly on what mb wants in there as well as climate and driving style. I live in so. cal. and sometimes traffic will leave engine idling in the heat and the 20w50 is really good in those situations.
I haven't read the TSB but take it easy as you approach the time to have the oil changed. Also, don't ever go in the red area in the tach.