# 2007 Toyota 4 Runner weird noise at start up - Hums

**URL:** <https://community.cartalk.com/t/2007-toyota-4-runner-weird-noise-at-start-up-hums/149735>\
**Category:** Maintenance/Repairs\
**Tags:** toyota\
**Created:** [September 29, 2019, 10:50am UTC](https://community.cartalk.com/t/2007-toyota-4-runner-weird-noise-at-start-up-hums/149735 "2019-09-29T10:50:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![pembroke](https://avatars.discourse-cdn.com/v4/letter/p/b3f665/32.png) [@pembroke](https://community.cartalk.com/u/pembroke)\
**Post date:** [September 29, 2019, 10:50am UTC](https://community.cartalk.com/t/2007-toyota-4-runner-weird-noise-at-start-up-hums/149735/1 "2019-09-29T10:50:13Z")

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First of all 230,000 miles.  
Just began making a strange racket when started…sounds like a loud hum or fan running…right at the drivers dash. Thinking it might be the secondary airpump with leaking diaphragm goes away after 10 seconds…car runs great

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [September 30, 2019, 12:49am UTC](https://community.cartalk.com/t/2007-toyota-4-runner-weird-noise-at-start-up-hums/149735/2 "2019-09-30T00:49:36Z")

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Could be the ABS self-test activating. Another idea, an engine belt is worn and slipping. As rubber heats up it shrinks, and that makes the belt a little tighter after 10 seconds, which could stop the noise. Belt noise is typically referred to as a “screech”, or “squeal”, but might be described as a “hum”. A third idea, could be related to the HVAC system. Try turning it on/off, different modes etc, see if that has any effect.