# Car knocking in winter **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [February 24, 2015, 9:15am UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131 "2015-02-24T09:15:40Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [February 24, 2015, 9:15am UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/1 "2015-02-24T09:15:40Z")
I thought I’d pass this on because I never think of it. We fairly regularly get posts about knocking noises when going over bumps. Well, today was my turn. My car was knocking when I drive over bumps… and there are plenty of them in NH lately. Without thinking twice about it, I pulled over in a parking lot, got out, and used my cane to knock large ice chunks out from the rear edges of the wheel wells. Problem solved. This winter has been the “perfect storm” for formation of these chunks. As I was driving away I began to wonder how many of the “knocking” posts we get are from ice chunks. So I thought I’d pass the thought on for future reference. I just ran the temperature projections graph from NOAA and the temperature will be staying below freezing in NH through at least Sunday night (that’s as far out as the data goes), mostly WAY below freezing. My guess is that we’ll get some knocking over bumps posts and I thought it’d be a good thing to keep in mind. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [February 24, 2015, 9:23am UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/2 "2015-02-24T09:23:41Z")
Welcome to my world. Here in Minnesota, you always kick the ice fangs from the wheel wells before driving the vehicle. Tester ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [February 24, 2015, 9:43am UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/3 "2015-02-24T09:43:15Z")
They’re common in NH too, but this year has been particularly bad. I just posted because it’s a possibility for other posters that I simply never remember to suggest. Knocking the chunks off the wheelwells is sort of a reflex action. I do it without thinking. ---
**Author:** ![bloody\_knuckles](https://avatars.discourse-cdn.com/v4/letter/b/ee7513/32.png) [@bloody\_knuckles](https://community.cartalk.com/u/bloody_knuckles)\ **Post date:** [February 24, 2015, 7:43pm UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/4 "2015-02-24T19:43:01Z")
We call them “snow boogers”. They are not only annoying but dangerous as they can act like a giant brake pad, stopping the wheel from rotating when the suspension is under compression, and causing loss of control of the vehicle. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [February 24, 2015, 7:55pm UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/5 "2015-02-24T19:55:58Z")
**^** Many years ago, I can recall driving along the Garden State Parkway in the immediate aftermath of a large snowstorm. I was traveling in the right lane at ~40 mph, and a small FWD Oldsmobile passed me, going…way too fast…for the road conditions. What was most memorable about this experience was the sight of his right rear wheel which had stopped rotating, as a result of the ice build-up in the wheel well. Even though he didn’t realize it, that foolhardy driver was **literally** on the hairy edge of losing control of his car. ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [February 25, 2015, 1:45am UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/6 "2015-02-25T01:45:11Z")
We have been cold enough here that many times you can not kick them off. The last time it was above freezing was Jan. 26. Many of our towns are using 50% sand and that doesn’t lower the freezing point as much as salt. ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [February 25, 2015, 4:17am UTC](https://community.cartalk.com/t/car-knocking-in-winter/89131/7 "2015-02-25T04:17:29Z")
I don’t know for sure if it was ice in the wheel wells or or struts or somewhere else. The day after a long slushy drive, I had no suspension, ie every bump was a hard one. The ice was too hard to kick loose, but in time it recovered. Another car knocking story, starting it up in cold it sounded like the worst lifter noise you ever heard, ended up being the tensioner was shot.