Engine Mechanical problem
1997 Ford Explorer 6 cyl Four Wheel Drive Automatic 138000 miles
I've got a loud rattling noise from the engine compartment. The loudest spot I could hear with a stethoscope was from the driver side exhaust manifold. It looks secure though. I don't see any movement from it.
The noise sounds like it's coming from the center or right side of the engine. The noise is also loud underneath, but everything is loud under there when it is running.
I wondered if it could be a lifter, spring, etc. But when listening through the tappet cover it doesn't sound all that loud.
Also, this only occurs at a low or rough idle and quits if I rev up the engine. This leads me to think the noise is external and is something loose that is rattling due to the irratic idle of the engine. What is your idea on this? Could a bolt be caught somewhere and cause this noise?
A good example of the noise would be like someone is tapping on the external side of the exhaust extremely fast or like someone is shaking a few pennies inside of an aluminum can. It is a high pitch rattle like something is hitting thin metal. I was wondering if a bolt got trapped behind the driver side manifold that I don't know about, but space is so tight I just don't know how I'll ever find that out. I also had someone else (not an certified mechanic) listen to the sound just to given an idea of what it sounded like and he said he thought he could hear an exhaust sound with the rattle at times, like a " poof" or passing of exhaust gas that triggered the rattle. I couldn't say much on this because I find the rattle so loud I can't hear anything else.
I know this description and the details I've given aren't a whole lot of help, but if anyone has any idea what this might sound like I would sure appreciate your opinion on the matter.
A question for you does the engine shake? If so you could have a bad engine mount. You should take a look at the heat shield on the Catalytic Converter. The spot welds may have broken in a couple places causing the rattling.
While at the cat take a rubber mallet and hit the cat or the pipe just in front or brhind it. If you hear something rattle then it is time to replace the cat. The internal material is starting to brake apart.
July, 24, 2010 AT 7:20 PM
The engine only shakes when the engine is running rough, otherwise no it is quite smooth. This happens at times, particularly when the engine has been idling for a long period of time. As for the heat sheild on the cat, it doesn't seem to be loose. The noise also seems to be closer to the engine than where the cat is located.
July, 24, 2010 AT 8:44 PM
Yes it is a possibility, I didn't think of that cause I haven't come across it in quite a while. To give you a close gestement I need to know the 8th digit of the vin.
July, 24, 2010 AT 8:48 PM
8th character of the VIN is E.
July, 24, 2010 AT 8:52 PM
Also, I don't know if it is the tensioners, guides, or what and if it's the front or rear. I have read if it's the rear the engine has to come out and it will require a special tool for the timing.
I don't even know where these tensioners are located at.
Since the truck is still running, thus the timing hasn't taken a walk on me yet, I'm wondering if I could replace the front tensioners (the screw in type from what I understand by reading other info on this) and see if that fixes the problem. Would I really need to replace the chain or anything if it hasn't broke or skipped yet?
July, 24, 2010 AT 9:47 PM
No as long as the chain hasn't jumped you don't really need to change the chain. You can try replacing the tensioner on the left side to see if by chance that is the problem.
Remove upper intake manifold. Remove thermostat housing. Remove left camshaft tensioner. To install, reverse removal procedure. If using a new washer, tighten to 32 ft. lbs. (44 N.m). If using old washer, tighten to 49 ft. lbs (67 N.m).
If that doesn't fix it then it look like the front of the engine will need to be torn down to replace the Guides or Cassetts as calls them.