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I own a 2004 Chrysler Pacifica. I have the car back to the ...
Sent to Car Experts November 04 09:34 AM

I own a 2004 Chrysler Pacifica. I have the car back to the dealer 4 times and they are unable to locate this problem. I have a "i call it a valve rattle" sound during acceleration below 2500 rpm. The sound goes away at higher speeds. This is very irritating and I feel that a major problem may manifest itself as more miles get on this car. Currently 17,000 miles on the car. Chrysler has done a valve adjustment kit on it, put new spark plugs and tune up, and then said it was the steering arm rattle. None of these help. I have tried Hi Test gas to see if this would eliminate this and it only behaves the same. I have even tried regular gas, same result. Almost sounds like some pre igniteion sound. Any thoughts ? John Foreman

Optional Information: 2004 Chrysler pacifica v6

Customer (name blocked for privacy)
Status:  Closed   Value: $10
Answer
November 4 9:58 AM (23 minutes and 35 seconds later)
         
REPLIEDCheck Mark
Hi,I need to know a bit more information.Does it make the same rattle when you gently accelerate,and when you put your foot down hard, rattle,but when you ease off the gas the rattle goes away?You say they did a tune up,can you tell me what they did.Did they put a engine mapping computer on,did they read the ecm,did they change the chip in the ecm?You are correct about the presumed noise being "pinking"or pre ignition,but the garage should have suspected the knock sensor.Have you had any codes read from the ecm?
Gordon Ball -- Engineer -- 100% Positive Feedback on 12 Car Accepts
BS,CPE,30 years different auto manufacturers experience
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November 4 10:07 AM (9 minutes and 34 seconds later)
         
Reply to Gordon Ball's Post: Gordon, I do not know if they put the engine on
a maping computer. If you put your foot down hard the rattle does go away. It also goes away when I back off the throttle. As far as the tune up, Chrysler dealer installed new spark plugs
"said they were fouled" ran cleaner through the engine " I do not know what type they used" They did not change the chip in the ecm. Again I do not have any code information to relate to you. I can call the Dealer and ask, this should be on thier computer. Could you tell me what they should look for and I will ask the Dealer. John
Customer (name blocked for privacy)
Answer
November 4 10:27 AM (19 minutes and 5 seconds later)
         
REPLIEDCheck Mark

Hello John,

It certainly indicates pre ignition.Can you ask garage if any faults came up when they read obd11 program from ecm,can they check the knock sensor.I am concerned the plugs were fouled that could cause pre-ignition(glowing carbon particles)on a car this young.I would ask that map sensor ,vacuum sensor,and repeating myself , sorry,the knock sensor.Are you using oil,is the oil mineral or synthetic?I am concerned you are having this type of trouble at 17,000 miles and yes ensure your warranties are current.

Gordon Ball -- Engineer -- 100% Positive Feedback on 12 Car Accepts
BS,CPE,30 years different auto manufacturers experience
Reply
November 4 10:34 AM (7 minutes and 26 seconds later)
         
Yes, I am using Mobile 1 synthetic oil and have since the car has been new. As I said the Dealer did replace the spark plugs but as soon as they did this the problem continued. This should have solved the fouled plug problem but, it did not.
I will call the tech. at the dealer and find out what came up on the map sensor for us and relpl to you. Question could this be a engine timing problem ? Could the knock come from the incorrect timing ? John
Customer (name blocked for privacy)
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November 4 12:57 PM (2 hours and 22 minutes and 42 seconds later)
         
Gordon, I just got a reply from the Dealer and nothing is showing up on any of the sensors. Pete Stobbs the service tech. said that a check engine light usualy comes on if something like this occurs but no indications on the computer. I knew when I used to race powerboats years ago that spark plugs come in varioius heat ranges, do you suppose we could try a platium tip hotter heat range type of plug to eliminate this problem?
Also any thoughts about my using synthetic oils ?
confused   John.
Customer (name blocked for privacy)
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November 4 12:59 PM (2 minutes and 38 seconds later)
         
Reply to Gordon Ball's Post: Still looking for answers ???
Customer (name blocked for privacy)
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November 4 7:05 PM (6 hours and 6 minutes and 6 seconds later)
         
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Gordon Ball -- Engineer -- 100% Positive Feedback on 12 Car Accepts
BS,CPE,30 years different auto manufacturers experience
Reply
November 7 8:26 AM (2 days and 13 hours later)
         
Gordon, Thank you for your reply. I have not talked to the dealer this morning "Monday" I had him keep the car over the wekend and drive it. He said there is nothing wrong but, I do know the preignition sound when I hear it. Now when I first purchased this car it had regular oil in the engine. I drove it back to my home in Tennessee from Atlanta and when it reached around 3000 miles I changed to Mobile 1 oil. Are you saying I should return to standard 10w/30 oil, Will this aid in reducing this problem ? Also what is over fuelling? No light appears on my dash as you have mentioned Thanks for the help John
Customer (name blocked for privacy)
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November 7 8:36 AM (10 minutes and 14 seconds later)
         
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Gordon Ball -- Engineer -- 100% Positive Feedback on 12 Car Accepts
BS,CPE,30 years different auto manufacturers experience
Reply
November 7 8:50 AM (13 minutes and 49 seconds later)
         
Then Gordon you are saying I should return to regular 10w/30 or with this information should I now return to 10w/40 ? . I still cannot reach the dealer this morning "Monday" and will reply if any additional information is received.
John
Customer (name blocked for privacy)
Answer
November 7 9:54 AM (1 hour and 3 minutes and 37 seconds later)
         
ACCEPTEDCheck Mark

Hiya John,

If the problem is clearances in the engine and that is causing oil carry over,yes go to a semi synthetic,10-30W SAE,and see if fouling stops.

Gordon Ball -- Engineer -- 100% Positive Feedback on 12 Car Accepts
BS,CPE,30 years different auto manufacturers experience
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