odd engine starting sound in 10F weather

[kenyee]

Anyone else have this interesting quirk only in 10F degree weather?

I made a video of the sound. In warmer weather (20F), the startup is just a vroom sound after you crank it. In colder 10F weather, it makes a whirrrrvroom noise, almost like the starter can't get out of the way or something.

video of engine startup

Of course, it never happens when I bring it to the dealer because these cold spells don't last that long...

I have the same problem. After starting rotate your wheel right to left if the sound gets louder add some PS fluid!

[kenyee]

This ML has been through four winters, two PS clamp replacements at the dealer, and a PS flush at the dealer already. This startup noise has happened every year at roughly 10F.

I'll try the rotate steering wheel thing, but doubt it'll act the same way as yours. After the engine warms up (I let it sit for about a minute until the engine revs drop), the steering makes no noise. Of course, we're in a virtual heat wave (34F today) now, so I won't be able to reproduce this until the next cold wave or probably next year.

It just sounds a little weird on startup before the engine grabs. It's almost the engine fires up and spins the starter motor for a while at a higher speed than the starter motor wants to go (the high-speed whirrr noise that's precedes the vroom in that video I posted).

I topped of the PS motor last night. The whinnign sounds is gone! I would check your PS pump, it make be leaking again. Mine was just replaced 3 months ago and it looks like its going back!

[kenyee]

SilentMethod, have you actually listened to my video?
Listen carefully to the beginning of the engine start cycle.
I should take another video to show how it sounds normally, but I figured most people would know how normal MLs sounded :-)

Glad your whining sound is fixed. If it whined while moving the steering wheel, I'd suspect the PS fluid or motor as well. If you had your hoses come loose before, the motor tends to die after a while because it runs for a while w/o fluid.

I did attempt to listen, but the sound quality was poor.

Good Luck

[roadsession]

Originally Posted by kenyee

Anyone else have this interesting quirk only in 10F degree weather?

I made a video of the sound. In warmer weather (20F), the startup is just a vroom sound after you crank it. In colder 10F weather, it makes a whirrrrvroom noise, almost like the starter can't get out of the way or something.

video of engine startup

Of course, it never happens when I bring it to the dealer because these cold spells don't last that long...

Sounds normal to me... just coughs a little before starting up in really cold weather.

[kenyee]

Originally Posted by roadsession

Sounds normal to me... just coughs a little before starting up in really cold weather.

Except my brother said his C240 doesn't sound like that when starting in similar conditions...

And Drew hasn't heard it sound like that either, but they don't get as cold in Vancouver because of the ocean effect...

[Autobahner]

Kenyee

Can't say I've had that prob w my 2000ML, but can tell hint it may be the starter. When activated, the starter spins pushing a gear into the flywheel teeth which turns the flywheel (at least that's how it used to work). This sliding gear has lube on it which gets thicker in very cold temps. Possible the gear is hesitating sliding back into it's resting position due to grease becoming thicker in cold temp. This moment of hesitation (the noise) is likely the starter getting pushed for a second to a speed it is not designed to spin at - and it's letting you know it.