03 expy, 5.4L. i get a quick grinding noise related to the hvac system. if the unit is on when i start the vehicle, it makes a grinding noise for about 1.5-2 seconds. does not do it if the unit is not on when the truck is started. if the vehicle is running, and i turn the control unit on, it makes that damn noise...and it does it while driving as well. had a tech at work take a quick peek when i started the vehicle. he heard it, and said he saw something "shake" on the passenger side of the engine bay when it happened. very hard to duplicate, as it doesnt seem to want to do it when i bring a tech out! anywho, last week, an F250 came in with a similiar noise, and it turned out that the compressor ran out of oil, and was making the grinding sound. GREAT, i ordered a compressor, and spent a total of $475(part included) to have it installed.....

still makes that damn noise. this has been going on for awhile, and i fear i may damage my engine by driving like this.....PLEASE HELP!!

-jon

 

Try this, take the serp belt off and try to make the noise. If the noise is still there, then its internal.

 

wont the engine not run with no belt??

 

PROBLEM SOLVED:


Special Service Message OASIS SPECIAL SERVICE MESSAGE NUMBER: 19311

MESSAGE TITLE: 2003-2006 EXPEDITION/NAVIGATOR - MINIMIZE GRUNT/POP NOISE BY
TURNING A/C TO VENTBEFORE EXITING THE VEHICLE - DO NOT REPLACE COMPONENTS
APPLICABLE VEHICLES :
2003 - 2006 TRUCK : 00026 EXPEDITION 00106 NAVIGATOR

OASIS MESSAGE :
SOME VEHICLES WITH AIR CONDITIONING UTILIZING R-134A MAY EXHIBIT A MOMENTARY
GRUNT/POP AFTER BEING PARKED FOR SOME TIME & THE COMPRESSOR IS ENGAGED BEFORE
THE ENGINE COMPARTMENT HAS WARMED UP. THIS IS DUE TO LIQUID R134A BEING PUMPED
OUT OF THE COMPRESSOR. R134A WILL TRAVEL TO THE COOLEST POINT (THE COMPRESSOR)
ONCE THE ENGINE HAS COOLED, DUE TO THE DIFFERENCE IN TEMP BETWEEN THE ENGINE
COMPARTMENT & THE VEHICLE INTERIOR. WHILE MANY VEHICLES HAVE PCM STRATEGIES
THAT ADDRESS THIS BY REPEATEDLY CYCLING THE COMPRESSOR ON START- UP, THIS MAY NOT
TOTALLY ELIMINATE IT. REPLACING A/C COMPONENTS WILL NOT ELIMINATE THIS.
COMPONENT DURABILITY IS NOT AFFECTED. MINIMIZE THE NOISE BY TURNING THE A/C
SYSTEM TO VENT BEFORE EXITING, & IN MILD AMBIENT TEMPS (APPROX. 50-75F)
WAITING
A FEW MINUTES BEFORE TURNING ON THE A/C OR DEFROST.

APPLICABLE SYMPTOM CODES :
200000 ELECTRICAL
208000 ELECTRICAL CLIMATE CONTROL SYSTEMS
208999 ELECTRICAL OTHER CLIMATE CONTROL CONCERNS