Hello everyone! A while back I searched this site for info on a rattling diesel-like noise from the engine of my Endeavor (150K miles), when starting cold (40 or less degrees usually). Just thought others might benefit from what I found, so here goes...

Most techs told me that it was an engine knock caused by carbon build-up from non-premium fuel use. They figured this because the noise (which sounded much like a diesel motor) would last about 3 minutes then gradually fade away. Sooooooooooo, I tried many cans of Seafoam, both in the gas and the oil, as well as other professional grade intake cleaners, administered directly into the intake via the vacuum system. While it sure cleaned the intake system, it did nothing for the noise!!! Very frustrating and not inexpensive either!

Finally, I managed to leave it at my local mechanic (Little Bob's Auto, Winona, MN) and actually got it to duplicate the noise while he was present. After checking for noises and vibrations using the old metal-bar-to-the-ear technique, he zeroed in on the area of the timing belt cowling. He looked at the schematic and deduced that the only thing in there that could cause such a noise (and more importantly, a noise that GRADUALLY goes away) was the hydraulic timing belt tensioner! $70 in parts and about 1.5 hours labor and the noise is now gone for good! It makes sense........... the tensioner (when working correctly) applies immediate pressure to the belts. When leaking hydraulic fluid (it's like a small shock absorber), like mine was, it needed to warm up first before it would provide enough force-pressure to keep the belts from slapping around, causing the noise. Problem fixed!

I hope this helps someone else! Good luck!

 

Thanks for posting this! I think I've been experiencing this noise with my '04 Endeavor LS.

I've been dealing with the timing-belt area rattling situation by turning the car off the second I hear it (always on cold starts). When I start the car again (wait time doesn't seem to matter), the noise is gone.

I'll try this out.

In the mean time, I can't seem to figure out a fix for another whirring/soft rattling noise that comes from the transmission area. On cold starts, whenever the car is in gear (reverse or neutral) and operating at low RPM, I hear a soft rattling noise from the engine compartment area. This goes away at RPM greater than around 1,500 (comes back at low RPM if the car hasn't been running for 5 minutes or so) and after the car has warmed up. I haven't found any corroded exhaust shields and haven't found any other descriptions explaining this particular occurrence. Does anyone here have any ideas what it could be?

 

Did you figure it out? Ive got the same problem. It sounds like a loose heat shield to me too, but havent checked it out yet. I'm doing a timing belt in the next few days and planned to inspect some while ive got up on stands. I'll post if i find something