My car makes me seasick!

My car jerks me from side to side. It is especially bad when I have passengers in the back or luggage in the trunk. It is terrible on slick roads. Does this have something to do with tire pressure? Uneven wear on the tires? Suspension issue?

Model year?
Odometer mileage?
Current tire pressure?
Are the tires worn unevenly?

clk 230, 2003. I just had 2 new tires put on so I assume the tire pressure is correct. This has been an ongoing problem since I bought the car (I am the second owner).

Odometer mileage?

Additionally, I assume that the reference to “terrible on slick roads” is in regard to traction problems, not in regard to the side-to-side motion. Is that correct?
Can you elaborate?

Also–assuming that tire pressure is correct can be a fatal error.
If you don’t have a tire pressure gauge, you should get one right away. Check the pressure on all 4 tires and compare the readings to the placard on the driver’s door jamb. Correct if necessary, when the tires are cold (driven less than 3 miles) in order to get an accurate pressure. Re-check the tires at least once a month.

Go to a Ford dealer and ask to drive a used Crown Vic or Grand Marquis…Give the car a good test drive. How does the ride quality compare to your Benz??? If you feel the Ford is a vast improvement, unload the Benz, something very expensive is wrong with it…

odometer mileage is 95,000 miles

terrible on slick roads means the side to side jerking is really bad. It’s the same problem only much worse. I thought all wheel drive meant it would be safer on snowy roads but it seems to be worse.

No I don’t own a tire pressure gauge and have no idea how to use one. I will purchase one today. But would low tire pressure account for the fact that the jerking side to side motion isn’t constant? It’s almost non-existent when alone in the car but embarrassingly noticable when someone is in the back seat.

Does it have an automatic leveling suspension ?
It could be malfunctioning ride level sensor(s) or solenoids arguing about when to adjust the fill of each side, or just one side giving the illusion of rocking.
When you have more load in there leads me to the ride height sensors first.

hmmmm…how would I know if it has automatic leveling suspension? But that answer seems to make sense.

…by reading your Owner’s Manual, which explains all of the features of the vehicle.
Have you ever read it?

Sounds like you have a worn or broken suspension component. Get it checked out.

All Wheel Drive?? You just bought TWO new tires?? That’s a no-no…

I had the same feeling about only 2 tires but that is what the tire dealer said to do. I know nothing about cars (obviously) so have to rely on the “professionals.” They tell me I need 2 new tires, that is what I do. Do I go back and say I want 2 more new tires?

And no, I’ve never read my owners manual. I guess I rely on the mechanics to keep my car running correctly. I don’t know what most of it means anyway.

It means “Benz over”…Ignorance can be very, very, expensive…AWD repairs on a Benz will probably exceed the cost of the used Crown Vic I mentioned in an earlier post…

ok well I’m never going to drive a Crown Vic! I’m not 80!

The cops and taxi’s use Vics…There is a reason…You don’t have to buy one, just use the car as a gauge, a yardstick, with which you can better judge your Benz… You are the one who gets seasick, not me…

It looked to me like you were advocating buying a crown vic. I like the answers that maybe the worn suspension or the ride height sensors. And I will get my owners manual out and read it (and try to understand it) and I will buy a tire pressure gauge. But I think this is the reason the dealership can’t find an answer - there doesn’t seem to be any black and white answer. Sigh…it’s not bad enough that I want to go buy a different car because I really like not having car payments. I just don’t take any passengers unless absolutely necesssary. Then I feel like a dumb jerk for having an expensive car with a crappy ride.

Have you done the age-old, simple, “bounce test” for bad shocks and struts? Had an alignment shop check the suspension for damage?? If these things check out, next suspect is the All Wheel Drive System you mentioned… These systems use a “center differential” of some sort to allow the front and rear wheels to turn at slightly different speeds when cornering. That’s why all four tires must be EXACTLY the same size or this rather tender differential gearbox gets all nervous and starts doing bad things, like making you seasick. Should you have to replace it, your queasy feelings will be greatly increased…

So if the Vic just isn’t your bag, head down to your local Caddy Dealer and say "can I take a CTS out for a spin? No Geezer Mobile problems with this one…

You will find suspension specialists at a suspension shop (aka alignment shop). They will know more about the Benz suspension than a dealer’s general mechanics.
About the tires on an AWD (All Wheel Drive) vehicle: ALL the tires MUST be very near (say 1/10 inch), or undue wear, and erratic traction control responses, will occur. If one, or two tires are worn, and the others not, they will NOT be within the size (diameter) specification.

More clarification is needed here.

Is this a CLK (coupe) or a GLK (SUV)?
What is confusing me is that the CLK is not currently offered with AWD, but the OP states that this is an AWD vehicle. Was the CLK offered with AWD back in 2003? If not, then…

As to, “I’ve never read my owners manual. I guess I rely on the mechanics to keep my car running correctly. I don’t know what most of it means anyway”, it is fine to rely on mechanics to maintain your car, but you do need to have some idea of what maintenance needs to be done, and WHEN it needs to be done.

If you rely on mechanics for everything, then you will inevitably pay for needless maintenance in some cases, and will wind up skipping maintenance in other cases. Either way, it will cost you more money in the long run, either through duplication of maintenance services or repairs that resulted from lack of maintenance.

Also, most of the information contained in the Owner’s Manual tells you how to operate all of the systems on the car, from the audio system and the HVAC system, to the self-leveling suspension (if it has that feature). The manual also discusses really vital topics such as whether the tires have to be very closely matched if the vehicle has an AWD system.

Owner’s Manuals are written on an 8th grade reading level, so that any adult should be able to read and comprehend the information. Surely you are not telling us that you have attempted to read the manual and failed to comprehend it, so I have to assume that you have never even attempted to read it. If that is the case, you are not getting all of the service and enjoyment possible out of your vehicle, and you are also likely shortening its lifespan.

However, to return to the original topic, namely the side-to-side motion, I suspect that the vehicle has a stabilizer bar or anti-roll bar that is broken or disconnected. If the problem has existed ever since you bought it as a used car, it is likely that the first owner did not want to have to take out a second mortgage on his house in order to pay for the repair costs, and that he/she just dumped the car on an unsuspecting second owner.

Since a broken stabilizer/anti-roll bar is a significant safety issue, I strongly suggest that you take the car to a mechanic who is qualified to work on one of these German machines. This may mean returning to the dealership, but since it is very difficult to put a price on safety, you may just have to bite the bullet and pay their prices in order to have it diagnosed and repaired properly.

And, while you are sitting in their waiting room, you can begin to read the Owner’s Manual.
Trust me–you will understand what you are reading, and you will benefit greatly from reading it.

What kind of tire did you put on it. It makes a major difference on slick roads. AWD helps considerably if the tires actually have traction on slick roads. Many performance tires except select few are really poor in winter conditions.