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Dan, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1328
Experience:  Dealer Auto Technician
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Knocking from timing chain area, timing chain area and about

Customer Question

knocking from timing chain area
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: timing chain area and about two years
JA: What is the model/year of your Chevy?
Customer: 07 cobalt
JA: Are you fixing your Cobalt yourself? What have you tried so far?
Customer: replaced the timing chain the tensioner and sprockets and bad valves and head gasket
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 10 days ago.
Category: Chevy
Expert:  david craig replied 10 days ago.

Hi Im David, after replacing all of that you still have a knock? did you ever do a compression test?

Customer: replied 10 days ago.
no i havent
Customer: replied 10 days ago.
could it be the oil pump is bad
Customer: replied 10 days ago.
u still there
Expert:  david craig replied 10 days ago.

it could be a bad pump, but idf its been happening for 2 years you got more problems then a bad pump. its probably a rod knock from lack of crankshaft bearing lubrication and now theres movement of the piston connecting rod causing the knock.

Customer: replied 10 days ago.
no way to fix that also the car has jumped time twice
Customer: replied 10 days ago.
i was thinking maybe the chain is not getting proper lubrication
Expert:  david craig replied 10 days ago.

if the car has jumped time then you have bent valves.

Customer: replied 10 days ago.
what is your opinion
Customer: replied 10 days ago.
i replaced the valves
Customer: replied 10 days ago.
reseeted them
Expert:  david craig replied 10 days ago.

my opinion is always based on if it was my car. i would do another compression test. and based on those results, i would make the next decision.

Customer: replied 10 days ago.
also replaced crankshaft pully
Expert:  david craig replied 10 days ago.

do you a compression test.

Expert:  david craig replied 9 days ago.

checking in to see how its going

Expert:  david craig replied 8 days ago.


Expert:  Dan replied 5 days ago.

New expert here

I am contacting you because the post has not been closed or rated.

This question is coming up on 7 days which means it will time out and close.

You have already paid to get this question answered, but you have not rated.

Let me help some more. Is there anything else I can help you with?

If I did not give you 5 star service, please let me know what I missed.


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