Leak/high pitch noise from behind the dash | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Leak/high pitch noise from behind the dash


New Member
November 26, 2018
Reaction score
City, State
Year, Model & Trim Level
2003 4x4 XLT Explorer
I have a 2003 Ford Explorer 4x4, XLT, Ive added headers , custom exhaust , cold air intake, tuner and tires to her . ( all installed by class A mechanic ) I have spent roughly $10,000 + $3200 on replacing worn parts on the vehicle and replacing the transmission with a new rebuilt transmission.

Whenever I am driving or in idle there is a small leak sound coming from behind wear the heat and cold air adjuster is . At first I thought there was a leak in a line so I checked and found nothing.

I then noticed after taking the vehicle out again that whenever I accelerate the air leak sound turns into a high pitch whistle , whenever I slow down I there the pitch of the whistle drops as it slowly quiets down the more I slow down .

I’ve broughten the vehicle too two different mechanics who cannot find the problem , but one of the mechanics said he has the same year explorer that makes the same sound but he cannot figure out what the cause is!

Please let me know any possible culprits as this is my favourite vehicle I own and I hate when she squeaks and whistles at me !!!