2013 GLK with about 120,000 kms.

when driving at speed and slightly turning left like on a highway on ramp or curvy road, there a a faint rumble noise that is pulsating like VumVumVumVumVum... it only happens when I’m turning the steering wheel left and going around 40mph. Any faster and the wind noise takes over. I can also feel the pulsating rumble in the steering and my butt. It’s very faint but sort of noticeable.

The car doesn’t pull to the left or right and an alignment was done last year. It has new pads and rotors on the front. The front bearings are good I think. I tried wobbling the tire in and out when jacked up and it’s very firm and tight. No play at all. I didn’t check the rear tires though. I’m wondering what this can be. It only happen when turning the steering slightly left going at at speed.

Take it to a tire shop, the tire could have a broken belt, or needs balancing or a bad cv joint.

I checked the front wheels again and found play on the driver side wheel. Looks like I need to replace the wheel bearing.

I thought wheel bearings would last a lot longer than that

I took it to the shop yesterday and they determined it is the end link. The bushing is worn and it’s causing a knock when the tires are pushed at 9 and 3. We both saw play in the bushing. They will replace the end link tomorrow and then test drive again to determine the rumbling noise. It is likely the wheel bearing on the same side. I recall taking a trip down to Florida and driving about 120 km/h on the highway and there were a bunch of bricks on the road. I ran right over it at speed because I couldn’t avoid it. I really thought I blew my tire, but thank god I still had my 16 inch winter tires on. Maybe running over that brick caused premature bearing and end link wear.

All fixed. It’s the driver side toe rod end link and passenger side wheel bearing.