I have a new 2006 Ford Explorer, 4.0L engine, with only 6500 miles on it. At around 4000 miles I started to hear a squealing noise coming from the engine when the car is accelerated above 2000 rpm and the noise continues to 3100 rpm. Below this rpm it is smooth and quiet. When the gear changes (at > 3000 rpm) from 4th to 5th or from 2nd to 3rd, the whistling goes away immediately.
When I press on the gas to raise the rpm back to around 3000 rpm, which shifts it down one gear, the noise returns until the rpm increases above 3000 rpm, the gear shifts to the next higher, rpm goes down and noise immediately fades out.
I must add that this whistling noise can be heard clearly when the car is cold. After traveling for a long distance (specially long highway distances) this noise is very faint and sometimes it disappears completely at the said rpm values when shifting gears. But then the next morning the noise is back at exaclty these rpm values (fading away when the gear shifts). It is driving me crazy. I changed the transmission oil with no effect.
I am suspecting a bad water pump bearing is causing this, but wanted to get some opinions before going for this (warranty covered) repair. BTW, is the water pump gear-driven on the Explorer? Is replacing the water pump unit a big job, will they need to lift the engine?
Replacing the water pump is a fairly involved job.
Are you able to have someone push on the gas while you listen to various areas of the engine with the vehicle stopped and the hood open? If you can, you might be able to pinpoint where the noise is coming from. Let us know.
January, 12, 2007 AT 3:55 AM
Thanks for the reply. Actually this squealling only happens when the car is moving. I pressed on the gas with the car stopped and in Park. It only goes to less than 3000 rpm (does'nt allow higher rpm however I press on the gas). There is no noise at all any where in this stopped position.
January, 12, 2007 AT 4:00 AM
Aren't you still in warranty?
Oops didn't read the last line.
January, 12, 2007 AT 3:55 PM
Service Writer made a good point, you should still be under warranty which means you have a free ticket to the shop.
Since you heard no noise while the vehicle was sitting, then you can pretty much rule out the engine alone making the noise. Which means you shouldn't need to replace the water pump. I would look more closely into the transmission/drivetrain.
January, 13, 2007 AT 4:10 AM
I have noticed that the squeal dissapears when the outside temperature is above 77 degrees and the car starts cold, or when the engine temperature increases to normal operating temperature. When the outside temperature drops at sunset, the squeal returns. If it is not the waterpump, then what could be causing this temperature dependent noise? I am boggled!
The dealer does not have a clue what could be causing this noise. I wanted to get some insight from here before I took it in. I would'nt want them to take something apart that was not the cause of this squeal.
Really appreciate this service.
January, 13, 2007 AT 5:55 AM
Not sure if this applies, but there is a techinical service bulletin for a whistling noise at 40-70 mph (64-113 Km/h). Ref # 06-14-08
January, 14, 2007 AT 4:44 PM
I found the following TSB (but for a 2001 model year Explorer). This TSB is a close match to what I'm experiencing. What should I do under warranty? Change front axle fluid? Is there anything more I should ask the dealer to do?
POWER TRAIN: AXLE ASSEMBLY
TSB #01114 -- SOME 4X4 VEHICLES MAY EXHIBIT A HIGH-PITCHED SQUEAL OR WHISTLE TYPE NOISE FROM THE FRONT AXLE AREA OF THE VEHICLE AT SPEEDS FROM 16 TO 64 KM/H (10 TO 40 MPH). *TT (NHTSA ID #622642, JUNE 11 2001)
January, 14, 2007 AT 4:55 PM
You spent a lot of money on that truck, rightly you shouldn't have to be doing their job at this point. But I understand why you are. In theory, you should be albe to give the symptoms, they should be able to experience it and then diagnose it. Being at the dealer there is a higher percentage they have run into this. But some dealers have incentives to not warranty things. So I would take it in, tell them the symptoms and bring it when the symptoms are most likley to happen. Try to get someone such as the service manager to test drive it with you so he hears it. Inform them of the tsb, but let them decide how well it fits.