If you have vibrating headlights, my first suspicion is shot motor mounts (if more than 5 years old, or oil soaked, they ARE shot). Second guess is a loose mounting screw somwhere around the headlamps. Or something awry with your engine - injectors, rack damper, idle speed too low, needs valve adjust, etc...

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Dave
Boise, ID
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My best guess is that the idle may be a bit low but since I don't have a working tach (mystery problem, CA emissions car) in the car I don't know for sure how low it is. The lights are attached as they should be. The motor mounts being shot? Could be as well, as they are original but they are clean, no oil saturation at all. Valves are at spec. Rack damper, not sure what that is. A little pressure on the accelerator pedal takes care of the vibrating. Yes, low idle is probably the culprit.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Egads, man! If those mounts are original (please let's hope they're not), they are TOAST! Rubber wears out with age, not mileage! Fresh mounts will make a HUGE difference in that case. It's not a fun job but well worth the effort, IMO.

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Dave
Boise, ID
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The single biggest difference between federal and European lights is the lense pattern. Look at true Euros vs. Federal cars. The lens pattern is noticeably different between the two. The US strictly regulates the amount of light that can shine forward in low beam. I'm still playing around with the height of my Euros to get them where I like 'em, but they put out MORE light in a forward and offset right pattern than any US spec lens, even today.

I very certain that the mounts are original and they appear fine. There is no torsional movement upon acceleration of the engine which is the most obvious indicator of bad mounts. I have had other vehicles that were even older than this one with original mounts and they were fine. In fact my Cadillac and GMC as well as the rest of my "fleet" still have their original mounts as well. It's just that I have never heard of engine mounts going bad simply because they were over a certain age. I always inspect mounts for cracking, squishing or breakage but I have never taken age into consideration. I have worked on cars for about 25 years but I don't claim to know everything. I am always open to advice about anything auto-related someone has to share. The best advice that I have learned is to not fix what is not broken.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

New mounts are soft rubber and the rubber flexes, absorbing vibration. Old mounts will have hardened from age and atmospheric contaminints like ozone, etc. They can look fine but simply can't flex or absorb vibration like they did when new. Heat cycles affect rubber as well. It's possible that if the car had an incredibly easy life, in cool areas over the past 18 years, they might not be completely shot. It's just highly unlikely. They also collapse over time and this is VERY hard to see until you remove the old mount, and compare it on the bench next to a new one.

One more thing I'll toss out there is that old mounts can also have the bond to the metal supports weakened with age. This is no big deal until you need to panic brake. Shortly after I bought my 123 (before I had time to replace the mounts), my wife rear-ended someone who stopped suddenly. She slammed on the brakes and didn't hit the other vehicle hard at all - just tapped them, and crinkled the grille on the 123. However with the braking forces present, the powertrain was straining against all 3 mounts, and the slight impact was enough to tear all 3 mounts! The engine flew forward several inches, disconnecting the driveshaft coupling at the tranny, then it bounced back part way with the driveshaft slip joint separated & kinked at a 45 degree angle. I'd never seen anything like it, and neither had the MB shop who repaired it (I tried myself and couldn't do it). They needed to force the motor back *forward*, tear out the driveshaft, replace it with a used one, and replace all the mounts. Note that oil soaked mounts (from leaks) are even WORSE about this - oily mounts should be replaced post-haste, after fixing the leak of course.

Look at it this way. If the car had original tires from 1985 and the tread was perfect, would you still drive on them? Personally I wouldn't, at least not over about 30mph! I've heard some real horror stories about this. Check with some tire companies and see what they say about rubber more than "X" years old, regardless of wear - you might be surprised. But hey, if you think the mounts are fine, that's your prerogative! I just wanted to at least give you a heads-up...


Regards,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Dave, funny that you bring up the notion of ~20 year old tires. How many of us here still have the original spare in the trunk? Would you trust that thing over 30mph?

BTW, what's your lady doing driving a ratty ol' 123? I'm sure she'd much rather drive the 124!

Dave, you have given me a new perspective on the old mount issue. It makes a lot of sense especially with the example you gave. Yes, I totally agree that rubber gets hard with age and it cracks when it dries out. The engine bay is a very hot environment and is prone to drying out anything that was once soft and pliable. I fortunately live in a cool and moist part of the country (The Great NW) so most rubber stays well preserved but as far the engine bay goes, I guess it doesn't really matter where you live.
I have an interesting story for tires. I was in California a few years back looking at a '50 Cadillac sedan with only 13,000 miles on it that was all original right down to the tires. The owner had driven the car all the way to California from Minnesota, where he had bought the car, on those tires! That car appeared very well preserved and possibly the climate may have had something to do with it. There were some minor cracking it the rubber of the tires but they were still soft. The spare looked brand new!
I do appreciate the heads up on importance of the engine mounts and the consequences that may occur upon neglecting them.
Regards,
DJ

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Ugh - yeah, I know what you mean about the tire thing. WIth stock tires you can add the spare to your rotation schedule and replace it periodically. That's not an option with the 16's and 17's we run though. On my 124, the spare tire is going the way of the dodo to make room for my Soundstream Reference amplifiers. I keep a big can of "fix-a-flat" in the trunk, and have AAA+ membership. I've only needed a spare tire once in my life, AFAICR, about 12 years ago. Guess I've been lucky.

And yeah, the spousal unit is constantly harassing me to "just give her my blue car". Yeeaaah, like THAT will happen. The 123 isn't ratty though. It was in decent shape when I got it (PO had $13k in receipts!), and then I've spent a lot of time & $$$ fixing the damn thing. It's mostly rebuilt now, so I kinda want to have her drive it a couple years to get some use out of it. But yes, I do want to replace it before too long, and get her behind the wheel of a 201. She's small, and the 124 is still kinda big (she looks odd in a big ol' 123). A 201 would be perfect. Hopefully a 190D 2.5 with ABS, SRS, and whatvever else was optional back then... :p

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Dave
Boise, ID
Check out my website photos, documents, and movies!