2007 Mercury Mountaineer 4.0L
After quite some time of not being overly concerned by the one-second timing chain sounding rattle at cold startup, I suddenly have developed a loud rattle that stays from startup to full operating temperature. It seems to be coming from the front middle or left (drivers) side. After spending many many hours reading everything I can find on here, I am pretty sure I have a guide or tensioner problem, either the primary chain tensioner or the driver side chain guide. I guess its also possible it could be the balance to crank chain guide or tensioner, but that doesn't seem to sound too common. No noise from the back right side.
I'm getting close to beginning the tedious task of inspecting and R & R-ing the necessary parts as so excellently laid out here by 2000StreetRod and others, but thought before I start, if anyone might have had any experience with a later year 4.0 like mine, and be able to offer any additional words of wisdom, it might be helpful.
The car starts right up with no problem. I haven't been driving it since this louder rattle started. But I have let it warm to normal operating temperature, and when I bring it up to between 2000-3000 rpms, it seems to quiet down some, but seems very loud when I let off the throttle; in fact, I feel the need to ease it back down to idle speed. If none of the chains have jumped, it would seem a good thing to keep it that way.
I have run it a few times this way (let it idle), and have occasionally developed an P0300 and P0301 code (random misfire and cyl 1 misfire). I have cleared the codes and either they have not reappeared, or then have then reappeared after a few times of this starting from cold and bringing to warm idle cycling...not every time. The engine seems to run pretty good other than the rattle.
Despite all of my research, while it sounds as though Ford enhanced some of the guides and tensioners, maybe in around 2002 or so??, I haven't been able to find anything stating specifically what year(s) these changes were made, or if there were any others later. I do know about the improved primary chain tensioner, and I believe the metal reinforcement of the left side guide and maybe the right side also.
Also, I haven't seen anyone on here indicating they have had this issue with anything really even close to as recent a model year as mine. I'm thinking maybe 2004 was the latest model year where I have read on here about someone needing to address this timing chain issue. So, I feel like I should be a little surprised that I'm dealing with this at 145K on the odo.
There were some apparently minor changes to this engine that I'm guessing may have corresponded to the timing of some slight body modifications that occurred in the Explorer and Mountaineer beginning in model year 2006 and later (one-piece tailgate/hatch; redesigned dashboard; automatic trans shifter moved from the steering column to the floor; new seating/console design, etc.). I also have a '99 Explorer 4.0, and my '07 engine compartment is different in a few ways, including a redesigned upper intake manifold, the oil filler hole is on the passenger side valve cover instead of on the driver side; the engine coolant overflow/recovery tank is in the front versus the old being on the passenger side fender; the 07 no longer has the trans dipstick. I think there are a few other minor modifications but I believe the engine is largely the same and also with regard to the design of the cams, timing chains, tensioners, guides, etc. Am I right?
Also, some of the replacement parts and the OTC tool kit seem to limit the applicable years to those prior to my 2007; I'm not sure how much sense this makes.
Also, being AWD, mine would have a balance shaft, correct?
Any thoughts or experience with this later version would be greatly appreciated!!
My specifics:
2007 Mercury Mountaineer
4.0L
AWD
145,000 mi
Thanks,
Jeremy