Got a weird issue going on with the truck. I'll give the short version, I just had a bunch of service work done on the truck, 95,000 mile service, new spark plugs, new power steering pump (it was leaking) and now that I spent almost $1200 on service...I have a vibration at startup...happened the next day after my service work.

It only happenes when the engine has sat unused for 4-6 hours, or overnight. It does not sound like piston slap which has been beaten to death on this site and I have read at least a hundred posts on it, and found audio clips of it. It is way too fast of a vibration or knock (whichever you please) in my opinion to be piston slap.

Out of spite I just replaced my serpantine belt today for $35 from the local auto parts store. I went 96,000 miles on the original belt, and it looked fine, but seemed too loose to me, now that the new belt is on it is much tighter.

Should I consider replacing the tensioner too? I am supposed to go to the local ford dealer on wednesday to leave the truck for 6 hours to cool so they can hear the noise and screw around with it for an hour, but if I can solve the problem before then I'd love it (especially at their $92/hr rate).

What do you think? I am planning on recording the noise...I have the equipment to do that.

EDIT: OH YEAH, it is a 2001 S-crew


--JR

 

Let the truck idle with the hood open. Look at the tensioner and other pullies and see if theyre wobbling any.

 

Nice lookin truck slammajamma!

I did actually do that today after I put the new belt on, I did not see anything unusual that caught my eye. I was looking over everything pretty good to make sure the belt would stay in place.

I had another thought, doesn't make a lot of sense to me but could the starter be hanging up...or not disengaging right away? I know what they sound like when you grind them on an already running motor, but not what they sound like when you don't let off.

--JR

 

Best way I know to pinpoint noise is with a cut off broom stick. Hold 1 end at your ear and then place other end at varius spots until you find the noise loud and clear. The noise will be ampified through the stick just becarful not to get it into the belt, fan,etc.. You can buy a stepascope at the parts store but the stick always works for me......

 

Thanks

 

I did the first recording with a digital camera set to video mode. Immediately after I start the engine you hear the noise I am talking about for about a half second.

What do you think this is? (it may take a few to update, I just uploaded it)

http://www.youtube.com/watch?v=3jP5IbJ4U3g

The next recording will be done with a condenser mic and Firebox digital recording interface.

 

Official word from the dealer is the starter is hanging up. This is the dealership I bought the truck from in Wheatland Wyoming and we know him very well. Doesn't BS with you.

Now I get to go to the local guys and see if they agree.