racecannon

I'm looking for an S-class sedan that is extraordinarily reliable and gives the best combination of vintage Mercedes look with semi-modern technology. I've settled on a late 80's/early 90's W126. I'd like to know what sort of things to watch out for with this car. It may be a few months before I buy, but if I'm right about this being the correct S-class, I'll keep the car for years and years. Any pointers?, things I should watch out for while looking?
Thanks.

blync

I'm selling my mom's 88 420 SEL. She was the second owner and the car has 168k miles. She has taken the car to the same shop for years for service and the car has been very reliable and a Az car it's entire life (rust free, no accidents). If you are interested, let me know. I 'm going to list the car this weekend.

Thanks
Brian

C280 Sport

As with all older Mercedes or any car really. Make sure that A/C works. Make sure all the windows and sunroof work too. Found some common issues here as well. Remember its an old car here so things will go. My 420SEL has been rock solid as was the 300SD.
126 common issues.
The rear vent always blow cold air:This is normal as it is a fresh air vent. The heat is suppose to come from under the deats according to the air circulation diagram. To prevent this interfering with heater of rear passengers, close during the winter.

Light bulb indicator on but all bulbs are working-Contrary to popular belief that indicator isn ot checking whether or not a bulb is working but the voltage. A bulb that is out will return a no voltage and trip the light. A bulb that is under that socket rating will not return enough voltage and indicator light. A bulb returning too much voltage will trip trip indicator light. So if all lights are working, before you go tearing into the dash, check to make sure all the bulbs are proper setup or ignore the yellow light.

Shocks-If they are leaking, replace. Bounce test is not too good of an indicator for these cars as they are not the made to bounce like the wallowy Cadillacs. The ride probably will be gone way before that shows. Blisteins are most popular and usual choice to use.

Trunk leaks- This is a pre buy check spot. Before they try to sell you a whole new rear end for half your house, check the simple stuff. The leak can come from the anttennae seal, which is pretty easy to replace or the tail light seals. These things are rubber and in heat tend to dry out after a while. And sometimes it can be the rear widow. Rear window might be a iffy proprosition as there might be more rust than meets the eye. But if the area is small and no rust through spots, fix the leak first then the rust. No point in fixing the rust spots without fixing the leak. Sounds like common sense but know many shops do just that. They dont want to bother finding the leak but charge you an arm and ear to fix the rust spot.


Front end clunk- A mechanic's special. They will try to sell you everything under the sun as if your whole front end is shot. Many times it's not the case and usually unless your car been in a wreck or have actually damaged the metal components themselves, then 90% of the time there is no point in spending $300-500 per component. The bushings are usually replaceable. Some of them are a bugger to get out but they replaceable and will save you lots of cash that didnt need to be spent. And usually a front end clunk is usually the tie rod ends or guide rod bushings. Both are relatively cheap to replace and can bring back that new feeling all over again. -Had this same issue with my 420SEL NY Roads.

Rear end clunk over bumps- Sway bars usually. Had this too. Upstate NY roads.

Rear end clunk switching gears- usually Differential. Many people confuse the two. And before you go and replace a whole differential, try changing the fluid. If there are metal pieces i nthe old fluid, then it might be too late. If not, you might be just in time. Many forget to change that fluid.

Vibrations coming from middle of car usually at low speeds- Talking about the type of vibrations that feels like someone is shaking your tranny as you drive. This can be a weak flex disk. Get this fixed asap or you'll find yourself buying more than a flex disk. Flex disk is not too expensive but the labor can be. So check flex disk. If it has crakcs in it, missing bolts, or distorted, time to replace. Front one and back.


Tires dont balance right, vibrating, wont align etc- This car is not made for cheap tires. Michelins are you safe but can get pricey. You can experiment with different brands as I found many non michelin brands while I was on tour in Europe that worked very well but not many of those was DOT certified. Also the person aligning your car might not know what the hell they doing. Even if they aligned thousands of fords/chevys/dodges. This is a Mercedes and less room for error in this department. Once you find a guy that have it just right with your tires, remember that guy. I remember I had michelins on my 560 at one point. The guy who did the work did an excellent job. But when I had continetals, vibrations (Michelins was not avail. for that car in mid nowhere Missouri) came upon and that guy didnt know what to do with the balancing issue. Took it to a friend of his and back to normal.

Seat/window switches work only sometimes- The contacts is probably dirty. Clean the contacts and they should work good as new usually.

Slow sunroof- Before blaming the motor or cable, get some good sunroof grease and it can make a hell of a difference.

Aftermarket sounds systems- If any monkey try to bolt an amp to the rear of the trunk in your car, run and take your car with you. They obvious never installed anything or nor have a clue about the layout of the W126. The gas tank is right behind that metal wall and most screws will go through that. With gasoline, you're asking for a firework show at you expense.


Window motor work but window dont move up but will move down or slides down freely when driving- This is usually a $5 piece of plastic that is on the sliding jaw. These things can split in two and the sliding jaw cannot get a grip to roll the window up and down causing it to come out of it's place. I would just say replace the regulator as I have done on my 420SEL because chances are its going to break soon due to age.

My current 126 has just over 120k on it. One small small rust spot inside the door. Not bad for an 87.

Becks Imports

Keep en eye out for monovale, causing improper temperature control from the HVAC system. Also head gaskets, more common on the 560 but still a problem on the 420.

Then rear SLS suspension is problematic, and vacuum lock system as well. Watch out for poor fuel mileage/rough idle, which can be symptomatic of a bad fuel distributor which is very expensive. Valve body on the trans can go too, and then rubber bushings in the front suspension, ball joints, leaking steering box are all common problems.

Make sure you bring whatever car you intend to buy to a good indy shop or Benz dealer for a full PPI. Don't expect perfection, but try to rule out any major stuff.

Bruce

Snipe656

I have owned a few of the 126s and the thing that has bitten me is vacuum leaks. They tend to be under the dash for me too which makes them harder to repair. An easy sign of this existing is the air from your heater or AC will not blow out of the proper vents. Outside that then you are simply facing the issues most any 20+ year old car is going to have.

lwright2723

I had great luck with the Torsion / sway bar repair kit from alleuro.com p/n 1233236665K. easy to install and way cheaper that 1500 to replace sway bar. I guess it works for 126 and 123 chassis.