Hello! New to me W116...

[The Warden]

Hello!

I first heard of this site from a post on www.mercedesshop.com, and after briefly looking through things, it looks like a great resource!

I just acquired a '79 300SD a couple of weeks ago, and am just beginning to sort through things (just got her on the road on Sunday)...the car wasn't really loved in its past life, but I think it'll make a decent daily driver, and could be made into something beautiful if I have the finances (which, at the moment, I don't; broke college kid) and the car proves to be worth it.

Here's the good:

• Original California car = almost completely rust-free! There's a spot of surface rust right by the antenna, and a spot in the water gutter just above the left rear door, and a spot on the hood. I think it's all surface, and that's all there is (at least of what I've found so far; the underside certainly looks clean)
• Engine runs strong. She needs a thermostat, and I think there's a water pump replacement in the near future (I'm hearing the bearing making noise from time to time); otherwise, the engine seems flawless. I still need to adjust the valves, and I'll probably run a compression check just to be on the safe side. The non-EGR manifolds are nice
• The interior is almost immaculate. The dash has the usual cracks, I believe, but there's a Dash-Mat covering it all up, so it at least looks decent. There are a couple of cracks in the center armrest, and a couple of handles are missing. Thank goodness for MB-Tex! (for comparison, my '85 300D has leather seats that are almost completely trashed)
• The price. Other than picking the car up in L.A. and hauling it up here (and buying a starter), the car was free. I knew the guy who had it beforehand (it was his father's car, and his father gave it to him to "dispose of"), and he didn't want to deal with selling it...so he decided to give it to me.

And, for the bad:

• There is a noticeable shaking when the car is above 55mph (although it seems to largely disappear around 80mph; I'm not sure if it goes away at higher speeds since I'm too chicken to drive that fast on a public road). The shaking is mainly felt through the steering wheel, and is more violent on turns (especially lefthand turns, for whatever reason). Before the guy decided to give it to me, I was looking at buying the car, and this scared me away from paying $$ for it. I'm hoping that this is a simple tire/wheel issue (the wheels are all steel and mismatched, and I think the tires are mismatched as well...I have a set of bundt-cakes that I need to clean up and get tires for)...but, if not, any ideas what would cause something like that? Other than the shaking, the suspension and steering seem fine other than some looseness in the box (which, if my 123 is any indication, is normal)
• Miles are a big question mark. The previous owner replaced the speedo at least once (the speedo that's in there now is a 160mph unit, and if the part number means anything, came out of an R107), so I haven't the faintest clue how many miles are on the car. The engine was supposedly replaced about 50K miles ago with one that came out of a car with 150K on the odometer. I know that the speedo and the differential are matched to one another on the 126 chassis (so, if you change the differential to one with a different ratio, you also have to change the speedo head to one out of a car with the same differential in order to get a correct reading); is this true on the mechanical speedo on the 116 as well? If not, how do you adjust the speedo reading to compensate? Is the speedo cable a standard "drive and driven gear" setup on the back of the tranny, with different driven (or drive) gears determining how the speedo's calibrated?
• The ACC is dead in the water...without any diagnostic work done yet, I'm going to guess the servo and the amp are done for. The fan would blow with the ACC set to defrost, but only put out cold air (and the fan has since stopped working; might just be a fuse *fingers crossed* ). If I keep the car long-term, I'll probably get the digital upgrade, but it'd be nice to get a working heater for the interim. The AC compressor also seems to be frozen, but I haven't looked seriously at it yet.
• I'm getting what appears to be classic Lake Daimler symptoms (my pet name for the water-in-rear-footwell problem that's usually the result of clogged hood drains on the W123 chassis, but I'm not sure yet what would cause it on a W116). I mentioned this on a post on Mercedesshop, and the consensus there was that the windshield seal is the source of the leak. Given the cracks in the visible rubber, I tend to agree with this...although I noticed that the dash is dry. Does this make sense to you guys?
• Cheap paint job...someone put a MAACO silver paint job over the factory silver, and the cheap job is already starting to crack and peel. Unfortunately, I don't think I can get rid of the cheap-o paint without ruining the original paint, so if i keep the car long-term, I'll have to save up and get the car properly re-painted someday.
• Something may be up with the tranny...it seems to shift slow on occasion, and the shift points sometimes seem like they're not quite right (inconsistent, etc)...I'll have to look into this further at some point.
• I think the front wheel bearings may need to be repacked...I'm not getting the classic growling sound, but I am hearing something from up front that seems to follow wheel speed; not quite sure how to describe it yet (I've only put 50 or so miles on the car since I got it running).

I'm sure that more will pop up as I start getting further into the car, so I imagine you haven't heard the last from me... *evil cackle* I've been playing with diesel engines since I was 14 (starting with marine engines), and I bought my W123 300D (a federal emissions '85, and I flew out to Texas and drove it home) in 2002 and know it fairly well, but I'm new to the W116 chassis. So, I apologize in advance if any questions seem bone-headed or anything on those lines...and appreciate any help I can get. I also apologize for so many questions in one thread; I'm just excited I may start different threads with the "major" questions later on.

Here endeth the introduction Thank you for making this site available! MBShop is a great resource for drivetrain info, but it doesn't seem like there's much of a knowledge base on the 116 chassis...

[John Hubertz]

Welcome,

The shaking is likely a combination of factors - you might budget some hours and a few $$ to rebuild your front subframe - you didn't mention your miles but if only due to age it is likely that the four big mount pads on the corners (ebay, less then $75 for a set) and the a-arm bushings need replaced.  Not the hardest job in the world, and it can be done in-car.

Lower ball joints are notorious on this model, especially with the heavy diesel engine...  and of course tie rods.

You'll want to prioritize repairing this, because steering quality is a huge plus to these machines, and the steering box doesn't like vibration and is not inexpensive to rebuild/replace.

The front end is very simple and low-tech, any competent frame/suspension shop can help you diagnose it.  These cars are almost identical to medium duty trucks in the way the suspensions are assembled.

I'll leave it to others to help diagnose the water leaks....

[michaeld]

Warden,
I'm afraid I don't have any 116-specific lore to pass on to you.  Is most of your experience with 123s?  I dare say that will serve you well, save for the ACC system (and you already know about the electronic upgrade).

You mentioned a thermostat.  When I first got my 77 450SEL, I found myself running a little hot, and assumed (hoped?) it was the thermostat.  It turned out to be a radiator that was 30% blocked.  For $300 I got a recore that has worked to perfection (and the price would have been about half that had I done the removal/installation myself).  I now have a infrared non-contact thermometer that would help me with any future heat issues.  You could get one on ebay for about $35 if you shop a little bit.  If the car has its original radiator, it's probably clogged.  26 years is a long time for metal to hold water.

I agree with John that you ought to prioritize your suspension.  If it is starting to go, it will quickly wear itself out and multiply repair costs.  116 transmissions DO have a bit of a delay from the torque converter that you particularly experience in reverse gear.  But it should be smooth through the positive gears.  You might ask a tranny place that gives free estimates to drive it and tell you what they think.  A major problem with a trans is major bucks - even if your planning on a salvage unit replacement.  In your favor is the fact that these 116 transmissions are excellent and will keep going even if there are problems.  That goes for the engines as well.

Free is a good price; but as I'm sure you know there's nothing more expensive than a cheap Mercedes.  You might want to take a step back and look at the whole deal cost-wise before you start to make a bunch of expensive repairs.  You might be wiser to pass this baby on to someone else and use that money to buy a better representative of the w116 breed.  Or not.  But you should have some idea as to what total costs you will likely face before you start spending money.

I wouldn't discount the possibility of your leak coming from the chassis.  I'll simply have to take your word that the "Lake Daimler" effect (good name!) would come from a clogged hood drain (it seems counterintuitive to me).  One way to help identify the source of a leak would be to mask the possible candidates off one by one with tarp and apply a garden hose.  If you don't get water spraying up top with the hose, but only when you're driving in the rain, I'd say your issue is in the chassis sheetmetal.  Obviously, if this leak isn't taken care of soon (assuming it's not already too late) you'll need to replace some rusted metal.

My 116 also has a 160mph speedo, so that's certainly not an indicator in itself that the unit has been replaced (but maybe it would be in a diesel?).

In any event, welcome to the forum.  I love your enthusiasm.  I hope that your car is a "keeper" that won't break your billfold.

Mike

[Tomi]

Hi and welcome,

I think the 116 is quite a bit like 123 except everything is bigger or more complicated requiring more work.

about the shaking, almost certain it comes from the unbalanced wheels. You might need to check the wheel alignment as well. The bearings are also a question, these could be the problem too.

The ACC is a common problem, and here you have several options

The tranny, when have the tranny oil been changed. If you dont know, change it and filter right away. If it has been changed, check oil level and adjust pressure. Usually this should be enough to make it work.

The leaking of water inside is much like in the 123. But in addition in the 116, the fuse box area (specially under it and the hood cable entry area are vulnerable to leaks, as well as rust in the firewall in general (as in 123) and in the air intake grill below the windshield. The front wheel well towards the driver feet should also be looked at.


Good luck, Tomi

[John Hubertz]

Could you add a few pics warden?  Or if you want, email them to me at fullhappyfish@yahoo.com and I'll post them for you.

[The Warden]

Thank you all for the welcome!

The shaking is likely a combination of factors - you might budget some hours and a few $$ to rebuild your front subframe - you didn't mention your miles but if only due to age it is likely that the four big mount pads on the corners (ebay, less then $75 for a set) and the a-arm bushings need replaced.  Not the hardest job in the world, and it can be done in-car.

Lower ball joints are notorious on this model, especially with the heavy diesel engine...  and of course tie rods.

You'll want to prioritize repairing this, because steering quality is a huge plus to these machines, and the steering box doesn't like vibration and is not inexpensive to rebuild/replace.

The front end is very simple and low-tech, any competent frame/suspension shop can help you diagnose it.  These cars are almost identical to medium duty trucks in the way the suspensions are assembled.

Good to hear that the front end isn't rocket science I'm a bit of a novice when it comes to chassis/suspension work, but I'm also crazy enough to try anything once Is the 116 steering box the same one used in the 123? The mount pads don't sound too horrible at all, at least from a pricing perspective...I'll have to get under the car once the ground dries up and see what you're talking about, and see how difficult it'll be to figure out. Certainly, since I have no idea how many miles are actually on the car, it might be good PM. On that note, any suggestions on a shop manual? AFAIK, the only manuals Haynes makes for M-B's are for the 123, 201, and 107. I know that CD's of the factory manual exist (and, because I have a friend who works as a tech at an M-B dealer, I think I can get the CD from him), but something on paper would be nice as well.

Is most of your experience with 123s?

As far as M-B's go, yes. A friend of mine has a 126 300SD that I've done some work on, but most of my M-B wrenching to date has been on my 123, and all of my M-B experience has been on the OM61x engine series. In case you couldn't tell, I'm a die-hard (some have said "fanatical") diesel guy. I'm also pretty good with the '80-'86 Ford full-size pickups (did a top-end rebuild on my 6.9l IH diesel in 2004 and a transmission swap {4 to 5 speed} in 2005), along with the -71 Series Detroit and the 1710 Cummins.

You mentioned a thermostat.  When I first got my 77 450SEL, I found myself running a little hot, and assumed (hoped?) it was the thermostat.  It turned out to be a radiator that was 30% blocked.  For $300 I got a recore that has worked to perfection (and the price would have been about half that had I done the removal/installation myself).  I now have a infrared non-contact thermometer that would help me with any future heat issues.  You could get one on ebay for about $35 if you shop a little bit.  If the car has its original radiator, it's probably clogged.  26 years is a long time for metal to hold water.

You make a very good point...but my gauge's actually reading low. It barely gets over the halfway mark between the 100 mark and the 175 mark (I guess, whatever the Fahrenheit equivelant of 60 degrees Centigrade is; I'm too used to the metric gauges on my 123). It might be a bad gauge; I want to get a thermometer or a mechanical gauge to see what the temp's actually doing...but this is about the same way the thermostat on my 123 failed, so my guess is it's opening too soon. Actually, after doing some mountain driving on Sunday (including some decent climbs, with three people in the car and trunk full of tools), I think the cooling system's in great shape (assuming the gauge is any good)...the needle moved around a little, but never got more than a needle's width above the mark between 100 and 175 degrees F.

I agree with John that you ought to prioritize your suspension.  If it is starting to go, it will quickly wear itself out and multiply repair costs.

I agree completely. This is actually the mistake I made with the 123...it had bad guide rod mounts when I first bought it, and that has since led the rest of the front suspension to deteriorate to the point where I figure that it'll cost upwards of $750 just in parts to repair it. Given the condition of the body and the interior, that's more $$ than I want to sink into the 123; hence the position I'm in now. I just hope it's early enough in the game that getting the front suspension happy won't cost an arm and a leg...

116 transmissions DO have a bit of a delay from the torque converter that you particularly experience in reverse gear.  But it should be smooth through the positive gears.  You might ask a tranny place that gives free estimates to drive it and tell you what they think.  A major problem with a trans is major bucks - even if your planning on a salvage unit replacement.  In your favor is the fact that these 116 transmissions are excellent and will keep going even if there are problems.  That goes for the engines as well.

Good to hear, regarding the delay...I had a feeling that it was somewhat normal, but I'm also terminally paranoid The tranny actually shifts very smoothly (far more so than my 123)...just, in addition to that delay, it sometimes holds a gear longer than I would expect it to (again, based on how my 123's tranny performs). It may be normal; I'm not sure. I don't know how old the transmission fluid is, but the previous owner was diligent enough about changing the power steering fluid (very rare to see) that he PROBABLY didn't neglect it too horribly. That said, the car sat for about a year before I got it, so it certainly wouldn't hurt. And, while I have yet to deal with an M-B gas engine, I'm absolutely in love with the OM617...the 123's been the most reliable vehicle I've ever owned, and at least from a drivetrain standpoint, I see no reason that the 116 won't do just as well.

Free is a good price; but as I'm sure you know there's nothing more expensive than a cheap Mercedes.  You might want to take a step back and look at the whole deal cost-wise before you start to make a bunch of expensive repairs.  You might be wiser to pass this baby on to someone else and use that money to buy a better representative of the w116 breed.  Or not.  But you should have some idea as to what total costs you will likely face before you start spending money.

You make a very good point, and that's one of my reasons for being here (and you are of course absolutely right about the adage of there being nothing more expensive than a cheap Mercedes)...want to see what I'm getting myself into before I start sinking any serious $$ into this car. So far, I'm in it maybe $250 (cost of a trailer rental, fuel, registration back-fees, and a starter)...but I'm in a financial position where I'm willing to spend some $$ on a worthwhile pursuit, but simply don't have the capital to sustain a money-pit. So, I'm going over this car with a fine-tooth comb before I start putting any $$ out...and, like I said, I'll probably be very active here in that process. This process may be a bit slow due to the fact that I have to put a lot of time in to school as well. We shall see, eh?

I wouldn't discount the possibility of your leak coming from the chassis.  I'll simply have to take your word that the "Lake Daimler" effect (good name!) would come from a clogged hood drain (it seems counterintuitive to me).

That was in reference to the 123, not the 116...in fact, I have yet to figure out if the 116 even has hood drains (although I don't think it does). The 123 has these pockets that the hood hinge tucks into when the hood's closed (because of the 90 degree feature, the 123 hood hinge is more complicated than the 116's). There is a drain out of this that tends to get clogged with leaves...and, if that drain gets clogged enough, the water overflows and goes back...somehow (I don't know how either) getting into the rear footwells. I agree with you that it seems counterintuitive, but clearing the hood drains and doing nothing else immediately (and, so far, permanently, after 3 1/2 years) cured the Lake Daimler problem. I was just wondering if there was something similar (some sort of hinge drain that I hadn't found yet, sunroof drains, etc) might routinely cause this on the 116, or if there's something else I should be looking for.

One way to help identify the source of a leak would be to mask the possible candidates off one by one with tarp and apply a garden hose.  If you don't get water spraying up top with the hose, but only when you're driving in the rain, I'd say your issue is in the chassis sheetmetal.  Obviously, if this leak isn't taken care of soon (assuming it's not already too late) you'll need to replace some rusted metal.

There's a possibility you're right there, but again, I think the underside is pretty clean from a cancer perspective; again, I think this car spent all of its life in California (and most to all of its life in the metro L.A. area before I acquired it). I really need to get the car on a lift, though, to tell for sure.

My 116 also has a 160mph speedo, so that's certainly not an indicator in itself that the unit has been replaced (but maybe it would be in a diesel?).

The PO specifically told me that the speedo was replaced. I could be mistaken, but I think that '78-'79 diesel 116's got 120 mph speedos, and all '80 models got the 85 mph speedo. I still need to figure out if this speedo's reading correctly...

I hope that your car is a "keeper" that won't break your billfold.

Time will tell, but I certainly hope so!

I think the 116 is quite a bit like 123 except everything is bigger or more complicated requiring more work.

That assessment makes sense...I know that, when I was a newbie to M-B's, I had difficulty telling a 116 from a 123 unless I could see the front end. It's like the 123 is the 116's younger brother, like the 124 is to the 126. Even still, there seem to be just enough differences to be a new learning curve.

about the shaking, almost certain it comes from the unbalanced wheels. You might need to check the wheel alignment as well. The bearings are also a question, these could be the problem too.

I'll probably summarily do the bearings, around the same time as doing the wheels/tires...and you're right on the alignment. The steering wheel is offset when the car's going straight, so there's at least something minor there...and, if the ball joints, tie rods, etc. are happy, the gearbox needs to be tightened up (but what M-B's box doesn't? )...just have to make sure it's not too tight.

The leaking of water inside is much like in the 123. But in addition in the 116, the fuse box area (specially under it and the hood cable entry area are vulnerable to leaks, as well as rust in the firewall in general (as in 123) and in the air intake grill below the windshield. The front wheel well towards the driver feet should also be looked at.

Good places to start...thank you!

Could you add a few pics warden?  Or if you want, email them to me at fullhappyfish@yahoo.com and I'll post them for you.

I've got quite a few pictures, and the ability to take more (digital cameras are our friends )...does this forum software support uploading pictures as attachments to posts? I haven't had much of a chance to play with the software yet, but haven't readily found a way to do so...if nothing else, I have some webspace that I can upload them to after I get home (I'm in school in between classes at the moment).

Thank you all again!!

[John Hubertz]

Many of us use the free www.photobucket.com to post pics.  It works super-smooth and you can simply copy/paste the links they provide under each uploaded pic.

Don't forget possible sunroof issues - at least I've heard more then one person mention that as a potential leak source....also door gaskets can be leakers on these.

One handy new method is the "smoke test" bodyshops use.... it fills the car with odorless smoke and slightly pressurizes it, and you can see where any porosity or major leak points are.  It is a phenomenal new technology and pretty cheap.

[OzBenzHead]

... One handy new method is the "smoke test" bodyshops use.... it fills the car with odorless smoke and slightly pressurizes it, and you can see where any porosity or major leak points are.  It is a phenomenal new technology and pretty cheap.

Ha! John - perhaps you could get a job for your smokin' avatar pooch!   

I like the idea. Any clues on how they make odourless smoke? I've not heard of the technique before, and just called my body man to ask if he'd heard of it. Answer: No.

[John Hubertz]

I'll call my body guy and ask where he got his setup.

[The Warden]

Sorry for the delay in replying; was busy with some schoolwork that completely swamped me over the past few days.

I threw together a page with some pictures real quick; take a look here. I think all the links work. Let me know what you guys think!

John, I like the smoke test idea...I wonder if I can find someone around here who has any idea what that is? It's certainly worth looking into...

Richard, I love my truck!! The old mechanically-injected 6.9l doesn't have the power of a new 7.3l Powerstroke (although adding the turbocharger and turning up the injector pump in '04 helped things ), but it's a lot easier for a shade-tree mechanic to keep on the road. I don't get to drive the truck that much due to the cost of diesel...but my truck's my baby. Other than climbing up the Grapevine, the truck towed the 116 like there was nothing back there at all (and, with the car, the trailer, and the truck, I figure the engine must have been pulling 13K lbs), and got 16 miles per gallon doing it! If I keep the speed down, I can get 20mpg out of the truck on a flat highway run...but, realistically, I'm seeing more like 17mpg in mixed city and highway driving.

I'm seeing 25mpg out of the 123 in mixed driving (she'll break 30 on a highway run if she's empty), and haven't driven the 116 enough to refuel her yet, so I'm not sure what sort of mileage I'll be seeing. If i keep the 116 long-term, I want to get a taller rear end under there...according to the parts numbers on http://www.adsitco.com/, differentials out of an R107, a W126, and a W123 will bolt into a 116, so I'd like to eventually get a 2.47 rear end out of a 380SL or something on those lines into this car (assuming I decide to keep her long-term). A few people have done it with W126 300SD's and were thrilled with the results...no real loss in acceleration, quieter freeway trips, and better fuel economy (and a higher top speed, although that doesn't do much for me)...

[Peter Anderson]

Hi Warden,

just checked out your web pages for the 300SD, very nice. Looks like a good project.

You ask on the interior shots, that you wished you knew what the air duct leading from the lower dash into the doors was for. Well along with the complex 'A' pillar design it is to keep the side windows clear as part of the cars innovative passive safety kit. The 'A' pillars deflect air away from the windows (so they don't get any rain on them, if you get rain in your part of the world!!!) and the air duct sends warm air from the heating system into the door skin, and this prevents the side windows from misting.

Best of luck, and nice to see the pics,

Peter
(from a very wet and miserable England!)

[John Hubertz]

DO NOT DRIVE THAT CAR.  THAT FRONT WHEEL IS NOT A MERCEDES WHEEL AND WILL COME OFF.

Mercedes, unlike all other cars, during the 70s and through the 1990s, use a very high pressure "dynamic stress" compression fit between the wheel hub surface and the hub plate to achieve a monolithic structure once a wheel is properly bolted on.  No other type of wheel is safe on one of our cars.  Especially on a 300SD which has more front end weight than any other 116, you MUST not drive that wheel.  Your shaking is almost certainly wheel flex or wobble due to the wheel bending or trying to break away.

[The Warden]

YIKES!!

John, to exacerbate matters...both wheels on the port side (driver's side) are identical to the front wheel on the starboard (passenger's) side. So, there isn't hte danger of one wheel breaking off...there's the danger of three wheels breaking off.

Just out of curiosity, you didn't seem concerned about the rear wheel...is that a Mercedes wheel?

Thank you for the warning. She's now out of commission until I get tires on the bundt-cakes.

BTW, I talked to my friend...my friend's father drove the car with these wheels for about 4 or 5 months before he moved and the car was parked until I got to it. Can this issue lead to other front or rear end issues that I need to be looking at?

[michaeld]

Warden,
Yeah, I can second that that front passenger wheel is not Mercedes-Benz.  I wouldn't have been as adamant as John on "don't drive that car!" - but that's because I don't know any better.  If you are having vibration or steering issues, that would be the first place to look.

I am actually posting because you mentioned some "issues" with the transmission.  There is an excellent and worthwhile book titled, "The Mercedes-Benz Technical Companion" that has some good info (and good answers to questions) on transmissions and many other subjects.  It's about $35 and worth every penny.

P.S. I only clicked on the "exterior" of your car, but it looks nice!

[OzBenzHead]

THAT FRONT WHEEL IS NOT A MERCEDES WHEEL AND WILL COME OFF.
Mercedes, unlike all other cars, during the 70s and through the 1990s, use a very high pressure "dynamic stress" compression fit between the wheel hub surface and the hub plate to achieve a monolithic structure once a wheel is properly bolted on.  No other type of wheel is safe on one of our cars.

John: Thanks for that very useful tidbit! I am aware that Oz Ford (Falcon) 14" wheels will fit most older Benzes - and know a few people who occasionally use them as spares. Being the purist that I am - and not having had the need - I haven't made that mistake, but I had no idea of the facts as you describe them.

Many thanks. That one goes into my "useful trivia" file.