Noisy start up, 2006

[B.G. Smith]

About 10 days ago I went out to go somewhere and started the truck, heard a mid range squeal from engine area. Shut down, opened hood and inspected what I could see, no blood, guts or hair visible and no cats missing from neighborhood.. Nothing out of the ordinary, started back up and all is fine. Have driven several times since with no unusual sound. Truck has 88,000 miles. bg

 

[petersonj]

Sounds possibly like a belt drive component. It may be worth your time to remove the serpentine belt and inspect each component for smoothness of operation. Water pumps on these trucks from 2003 through 2007 are notorious for leaks and premature bearing failure.

I learned something while replacing a water pump on a friends 2007 Cummins truck (2nd water pump - one at 65,000 miles and one at 130,000 miles). While the belt was removed and while I was inspecting all of the belt driven components, I noticed that the alternator used a one-way clutch pulley - called OAP's (overrunning alternator pulley) or OAD's (overrunning alternator decoupler pulley). I recognized it because I had to replace one on my wife's 2006 VW TDI alternator. The symptoms on the VW were very similar to yours - a one time squeal and then everything seems to be fine. It took me several weeks to figure it out. The engine ran fine, but it seemed that the idle was a little rough and I noticed excessive movement of the tensioner pulley at idle . It turns out that the squeal was a slipping one-way clutch on the alternator until it locked up and then behaved like a solid pulley from that point forward. I replaced the pulley with another OAP and the tensioner pulley became steady at idle and the engine idled smoothly again.

Your truck may not have this one-way clutch pulley, but it would be worth a look. If it does have one and it is locked up, I don't think it should be a problem to continue driving the truck - at least for awhile until you figure out the problem. It would behave as a solid pulley and I don't think you could tell the difference when your engine is at idle - large engine displacement would probably hide the symptoms as compared to the 1.9 liter VW TDI engine.

Anyway, hope you find the gremlin...

John

 

[cerberusiam]

The only problem with water pumps is the cheap replacements that are being used and lack of maintenance. A new Cummins water pump and coolant changes on a schedule will result in excellent service on the WP, like +150k in most cases.

What frequently happens is the belt will stretch enough or the idler spring get weak enough the belt will jump off one of the pulleys on start up or shut down, then, jump back on when the engine is shut off. Unless you leave the engine running and find the problem it disappears and nothing looks out of the ordinary. This stems from the quick shutdown of the engine and the rotating mass of the components, been an issue for many years. There is a TSB for the squeak on shutdown that replaces the alternator pulley with a sprag clutch to stop that which can lead to other tissue if the sprag gets worn or sticky. Just have to check and see if you have one of those installed and if the belt and\or idler is getting worn\weak.

 

[B.G. Smith]

Thanks for the replies. I haven't heard any more unusual noises. The overrunning clutch brought something to my memory. A couple of weeks ago one of my friends called and said her car was making a terrible noise, vehicle was a Chrysler Town Country. After some listening and probing under the hood with a stethoscope I decided it was the alternator bearings. Removed the alternator and turning it by hand it seemed very smooth, any way I took it in and it checked bad, got new alternator and installed and all is quiet. Did notice that the pulley on alternator had a plastic cover in the end where you would usually see a nut holding the pulley in place. Checked my truck and it also has a plastic insert in the end of the pulley. How about it Parts Guru MWilson? Do we have the alternator pulley with clutch? bg

 

[Bill Stockard]

BG,

Send Mike a Private Message. It's not likely he'll see the request in your post.

Bill

 

[petersonj]

(Checked my truck and it also has a plastic insert in the end of the pulley)

BG, I will bet that if you remove the plastic cover, you will see a female spline (about 30 teeth) that accepts a special removal tool. That will tell you that you have a one-way clutch pulley.

John

 

[mwilson]

(Checked my truck and it also has a plastic insert in the end of the pulley)

BG, I will bet that if you remove the plastic cover, you will see a female spline (about 30 teeth) that accepts a special removal tool. That will tell you that you have a one-way clutch pulley.

John

Don't remove the cover unless you are ready to change the pulley. It won't stay after you disturb it.

 

[mwilson]

Thanks for the replies. I haven't heard any more unusual noises. The overrunning clutch brought something to my memory. A couple of weeks ago one of my friends called and said her car was making a terrible noise, vehicle was a Chrysler Town Country. After some listening and probing under the hood with a stethoscope I decided it was the alternator bearings. Removed the alternator and turning it by hand it seemed very smooth, any way I took it in and it checked bad, got new alternator and installed and all is quiet. Did notice that the pulley on alternator had a plastic cover in the end where you would usually see a nut holding the pulley in place. Checked my truck and it also has a plastic insert in the end of the pulley. How about it Parts Guru MWilson? Do we have the alternator pulley with clutch? bg

Yes, we do. I checked my '06 yesterday and it does have the ADP (Alternator Decoupling Pulley).

I have a story and am going to start a new thread on the subject.....I just changed an ADP unit yesterday on my '02 Town and Country.