Ryan McDonald
Basic Member
Posts:191
 | | 21 Jan 2011 12:15 AM |
| So after a few searches, Im tossing a quick poll/trouble shooting question: 2000 D2 with 4.6L. Engine noise is exhibiting a "tap tap tap". This noise is present at idle, under load and corresponds to RPM. I have no appreciable loss of power, acceleration. But I may have recently noticed a drop in gas efficiency. No significant oil or other fluid leakage. Other "Vitals" remain stable. I'm thinking my choices are: a. valve lifters b. push-rod c. piston ring What am I missing? Do I need to open her up? Do I need to arrange for an "accident?" Thanks much for any info! | | |
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Benny Benson
Veteran Member
Posts:1681
| | 21 Jan 2011 12:24 AM |
| Exhaust leak. Timing belt/chain tensioner. | | | |
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Mike Rupp
Veteran Member
Posts:1354
| | 21 Jan 2011 06:35 AM |
| Diagnosing taps, clicks, and clunks are hard to do over the internet. Without being there, it's hard to tell if it is inside the engine or out. You might want to throw a quart of Lucas oil additive in and see if the sound changes. That will point to issues in the engine itself. | | | |
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Dan Cronin
Veteran Member
Posts:2844
| | 21 Jan 2011 07:12 AM |
| More than likely, a rocker arm cup has become dislodged. (Seems to be pretty common on the Rover V8's. | | | |
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Rob Stewart
Basic Member
Posts:428
| | 21 Jan 2011 12:03 PM |
| X2 on exhaust. Tap on the cats with a 2x4 and see if you get any rattles. Also check your ex. manifold bolts for looseness. Your 4.6 isn't from a 2003 Disco is it? | | | |
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Alex Kogan
Basic Member
Posts:421
| | 21 Jan 2011 01:57 PM |
| I'd suggest don't drive till you somewhat identified root cause at least. Get engine stethoscope or simply sufficiently long metal rod. Put one end against various locations around engine (don't stuff it into any moving belts!!!) other end (don't stuff into ear!!!) hold in you fist put that against your ear. Works just like wire telephone. You will distinctively here various parts of engine working. If it's bottom end then it is either your mains or rod bearing, middle could be piston ring or piston rod, top - could be rocker, worn camshaft, push rod etc. Some place else - you are probably lucky. | | | |
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Alex Kogan
Basic Member
Posts:421
| | 21 Jan 2011 02:00 PM |
| I seriously doubt it has anything to do with exhaust if as you describe noise corresponds to RPM | | | |
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pross
Basic Member
Posts:362
| | 21 Jan 2011 02:33 PM |
| You should try to get a vid up on here so we can hear it but sounds like rod bearings or guides but each has its own sound so a vid would help. how loud is it? | | | |
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Todd Eliason
Veteran Member
Posts:3515
| | 21 Jan 2011 08:27 PM |
| Posted By Alex Kogan on 01/21/2011 2:00 PM
I seriously doubt it has anything to do with exhaust if as you describe noise corresponds to RPM
The tempo of all of my exhaust leaks had everything to do with RPM. | | | |
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Ryan McDonald
Basic Member
Posts:191
| | 22 Jan 2011 12:16 AM |
| working on video... | | | |
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Rob Stewart
Basic Member
Posts:428
| | 25 Jan 2011 05:17 PM |
| Any luck tracking down your tapping? | | | |
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Tony Sims
Veteran Member
Posts:1231
| | 26 Jan 2011 08:00 AM |
| How many miles on the engine? Any difference in the tapping when in gear vs. neutral? Is it a sharp metallic sound like tapping a wrench on the valve cover, or what? Can you feel any corresponding vibration?
As you describe the noise as tapping and not knocking, I'm thinking external or top end, not crank/rods/bearings. Plus crank noises tend to lessen at higher RPM because unless the oil pump is dead it will manage to get some oil around things to form a cushion as RPM rises.
Start your investigation with all the stuff on the outside of the engine that moves, like all the stuff being spun by the serpentine belt, including the tensioner/idler pulleys (although those usually squeal from worn bearings). Be careful to keep fingers and clothing away from the belt, no need to add a trip to the hospital to your troubles.
If it's not external, focus on the push rods and rockers first. Could be as simple as a loose rocker. Secondarily the cam and cam followers (i.e. lifters) and the valves. Then timing gears and chain. | | | |
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Alex Kogan
Basic Member
Posts:421
| | 26 Jan 2011 10:15 AM |
| From personal experience. There is no way to tell knock from rattle, rattle from tap. Awhile ago I acquired Dodge Intrepid from police auction, sight unseen, very cheap, a bit bruised, 3.5 years old, only 21k! miles, just out of warranty. Soon it developed or at least I noticed a rattle which corresponded to RPM, really sounded like a loose bolt or something of that nature. S...t but using the rod technique (see above) It did came from the bottom. What can be so messed up with 21k vehicle. I don't shun away from opening things up. But never seen anything like that. Behold:
And of course source of rattle was not a loose bolt or or lifter or chain or whatever. It was connecting rod bearing: 
Long story short. Replaced bearings, made sure all clearances are to spec, cleaned up engine as much as I could.
Drove it several months just not to make sure nothing else is wrong about it. Fed it Mobil 1 and no knocks, no tapping, no noises, no sludge showed up again. Finally traded it in for 3 year old Montero. In the end made myself handsome profit.
Anyway I'll repeat again invest $5 in this tool. It's invaluable in identifying engine noises. Of course. Ha Ha. bought my TLC from same auction, comparatively cheap, comparatively low miles and behold. Of course it's like a plague for TLC but none the less funny. 
Now with new head gasket, new valve guide seals (all 24 of them), new PHH for those in the know, etc. Now seemingly runs like a champ. Taking that baby with intake attached off and putting back on was fun. It's no fun though how on right side of engine you can just climb under hood (and I spent good deal of time there) while on left side it's sometime almost impossible to stuff you hand through to reach some sensor with just tips of your fingers. | | | |
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pross
Basic Member
Posts:362
| | 26 Jan 2011 05:01 PM |
| There is a huge sound difference between an exaust leak, tapping valve, or main or rod bearing I'v been diagnosing cars and trucks for years just by listening to the engine its the way I was taught. | | | |
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Mike Kelly
Basic Member
Posts:469
| | 26 Jan 2011 11:25 PM |
| Of course. Ha Ha. bought my TLC from same auction, comparatively cheap, comparatively low miles and behold. Of course it's like a plague for TLC but none the less funny.
Now with new head gasket, new valve guide seals (all 24 of them), new PHH for those in the know, etc. Now seemingly runs like a champ. Taking that baby with intake attached off and putting back on was fun. It's no fun though how on right side of engine you can just climb under hood (and I spent good deal of time there) while on left side it's sometime almost impossible to stuff you hand through to reach some sensor with just tips of your fingers. This is dumb off topic, but that's not the Cruiser in your signature, right?
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Tony Sims
Veteran Member
Posts:1231
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| 27 Jan 2011 02:04 AM |
| Posted By Alex Kogan on 01/26/2011 10:15 AM From personal experience. There is no way to tell knock from rattle, rattle from tap. Awhile ago I acquired Dodge Intrepid from police auction, sight unseen, very cheap, a bit bruised, 3.5 years old, only 21k! miles, just out of warranty. Soon it developed or at least I noticed a rattle which corresponded to RPM, really sounded like a loose bolt or something of that nature. S...t but using the rod technique (see above) It did came from the bottom. What can be so messed up with 21k vehicle. I don't shun away from opening things up. But never seen anything like that. Behold:
That is hideous! WTH were they using for lubrication, banana peels?! | | | |
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Alex Kogan
Basic Member
Posts:421
| | 27 Jan 2011 07:46 AM |
| Posted By Michael Kelly on 01/26/2011 11:25 PM
This is dumb off topic, but that's not the Cruiser in your signature, right?
Yes. It used to say dead in water. Also it's not really family mover any more. | | | |
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Alex Kogan
Basic Member
Posts:421
| | 27 Jan 2011 07:54 AM |
| Posted By Tony Sims on 01/27/2011 2:04 AM
That is hideous! WTH were they using for lubrication, banana peels?!
Those Chrysler 2.7 V6 were notorious for sludging. It even had oil change history. Not that you would get too many in 21000 miles. One theory was: water pump is located inside the engine driven by cam chain. if it starts leaking minute amounts of antifreeze get into oil possibly causing this mess. Mine indeed was leaking. Only through the drain hole though I didn't see any signs of leak inside engine. I replaced it as well. | | | |
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Mike Kelly
Basic Member
Posts:469
| | 27 Jan 2011 08:18 PM |
| Posted By Alex Kogan on 01/27/2011 7:46 AM Posted By Michael Kelly on 01/26/2011 11:25 PM
This is dumb off topic, but that's not the Cruiser in your signature, right?
Yes. It used to say dead in water. Also it's not really family mover any more. Looks like someone put a pre-95 grill on her... any reason, or just preference? | | | |
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Alex Kogan
Basic Member
Posts:421
| | 27 Jan 2011 08:41 PM |
| It kissed something in it's previous life then front cowl grill and hood was repaired with some salvaged pieces. Interestingly front fenders are original and intact. | | | |
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