99 Chrystler 3.8L Engine Knock - HELP~



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Thread: 99 Chrystler 3.8L Engine Knock - HELP~

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    99 Chrystler 3.8L Engine Knock - HELP~

    Hi all:

    I am a new member and a new Chrystler Town and Country owner... a nice ride leather heated seats very nice. I'm impressed, never had one before.

    I have a problem, the engine knocks, raps, it sounds like in the tappet area a distinct knock. It's not at the rocker arm area, too heavy a sound, it goes down the road nice doesn't skip or smoke, just knocks.

    Today I tore it down, heads off, oil pan off... all the roller lifters look great, they all move like the same amount, the pushrods are fine and the rockers.
    I checked each connecting rod bearing*(it's got 162,000 miles on it) all the bearings are intact, wear is evident for sure but not so you would hear a knock, I expected to find one spun.
    Now I''m at a loss, I've looked at all the likely suspects and stilll no smoking gun~!

    Any thoughts will be greatly appreciated... I heard that the cams break on some of these... if the cam was broke it wouldn't run very well...

    HELP>>>


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    Quote Originally Posted by tommcmullen View Post
    Hi all:

    I am a new member and a new Chrystler Town and Country owner... a nice ride leather heated seats very nice. I'm impressed, never had one before.

    I have a problem, the engine knocks, raps, it sounds like in the tappet area a distinct knock. It's not at the rocker arm area, too heavy a sound, it goes down the road nice doesn't skip or smoke, just knocks.

    Today I tore it down, heads off, oil pan off... all the roller lifters look great, they all move like the same amount, the pushrods are fine and the rockers.
    I checked each connecting rod bearing*(it's got 162,000 miles on it) all the bearings are intact, wear is evident for sure but not so you would hear a knock, I expected to find one spun.
    Now I''m at a loss, I've looked at all the likely suspects and stilll no smoking gun~!

    Any thoughts will be greatly appreciated... I heard that the cams break on some of these... if the cam was broke it wouldn't run very well...

    HELP>>>

    Geez, I wish you'd found us before you tore your motor down. The fact of life is that pretty much all of these motors knock to a certain extent, our 1998 3.8 is no exception. This issue has been discussed a time or three around here and if I remember correctly the popular consensus is that the noise ie eminating from the timing chain and or the oil pump assemblies.

    FWIW, I replaced the head gaskets on our 1998 last summer as well (incorrectly thinking that I had a coolant leak from one of the gaskets), so I'm pretty familiar with the job you've just taken on.
    Sold: 1998 DGC Sport 3.8 (Final odo: 178,000 miles)
    Sold: 1998 Chrysler T&C LXi 3.8 (Final odo: 190,000 miles)
    Sold: 2003 DGC ES 3.8 (Final odo: 172,000 miles)
    1999 Chrysler T&C Limited 3.8
    2001 Honda Accord EX-L V6 (4-Speed automatic)
    2012 VW GTI (6-Speed manual)

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    Wow, your ambitious my 3.0 liter had a little tick to it - I added some "Kendall High mileage oil" to it and viola Noise gone!!! I do not know that much about the 3.8 L although they are supposed to be a much better engine than my 3.0L I was told that the noise in mine was a collapsed lifter and apparently all the 3.0 do it. Good luck I am sure someone here knows how to help you!
    "IT'S HARD TO LEAVE WHEN YOU CAN'T FIND THE DOOR!!!

    2003 Grand Caravan Sport 3.3L
    2004 Honda Civic
    A Few Boats and a Sled (not a dog sled )

    Former Chryslers:
    2000 Dodge Dakota
    1993 Plymouth Acclaim
    1996 Voyager 3.0L
    1999 Caravan 3.0L

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    [QUOTE=shipo;63411]Geez, I wish you'd found us before you tore your motor down. The fact of life is that pretty much all of these motors knock to a certain extent, our 1998 3.8 is no exception. This issue has been discussed a time or three around here and if I remember correctly the popular consensus is that the noise ie eminating from the timing chain and or the oil pump assemblies.

    FWIW, I replaced the head gaskets on our 1998 last summer as well (incorrectly thinking that I had a coolant leak from one of the gaskets), so I'm pretty familiar with the job you've just taken on.
    ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++

    This motor had KNOCK, I've never heard a knock like that and not find a smoking gun inside... I'm really exasperated at this point not finding anything.
    I'm sure if I put it all back together it will knock like I never touched it...
    How can a timing chain make a knocking noise>?
    Another thing; no debris in the oil pan, no metal, no parts, or broken parts... no shavings...

    Thanks for you reply, let me know about the chain and pump, how do they knock?


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    I concur with the timing chain noise issue. My van has a little bit of timing chain noise at idle. An older 3.3L I worked on last fall had a lot of timing chain noise. I think the chain just beats against the metal chain guide once even a tiny amount of slack develops. The chain has no damper to take up slack.

    - G
    1998 Grand Voyager @282,000mi, 3.3L FFV V6

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    tommcmullen - are you sure it isn't just piston slap?
    1998 Grand Voyager @282,000mi, 3.3L FFV V6

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    Check to see if your torque plate is cracked. This problem is actually more common than you would think. Remove the tin plate on the bottom of the bellhousing (I think it is held in with three small bolts) If you can move the torque converter any distance back and fourth with no resistance -rotation, not fore and aft... you have a cracked torque plate. If cracked, you will not be able to see the cracks until you remove the transmission. They crack arround the crank shaft bolts. Quick and easy to check. The torque converter should move, but have no "free play".
    These engines are bullet proof, it is unusual to find problems with them.0

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    I don't think it's piston slap, as best I could see everything with the pistons looks a-ok... I'm not taking them out if I don't need to.

    The flex plate... I was thinking about that too, it seems tight...
    The knock is real pronounced when the engine is cold, like a collapsed lifter, but with no skip, then when the rpms are brought up to 2500 or so holding there the sound is like a bad rattle, but no scraps in the pan.

    I'm going to check the flex plate again... the timing chain is loose, i can feel it and see it, can't imagine how it would make that noise but, I'm so close now there is no backing up.

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    When my flex plate went it was worse for some reason when the A/C was on. After looking and looking I thought it may be the torque converter. I called my local dealer (Goss Dodge in South Burlington, VT, Great folks) They said from my discription they were sure it was the torque plate. When I asked them if this was common, the service manager told me that they had just done three of them...
    I could easily turn the ring gear back and forth about 3/8', then it started to hit some resistance. The frustrating thing for me was there was no way to see the problem to be sure it was the problem until after I removed the transmission. The good news, it was the torque plate and I really did have to remove the transmission. The bad news, my torque plate was shattered.

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    Check all the bolts holding the flywheel to the torque converter. Iahve heard them make on awful knock

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