Cobalt Engine Problems

  • 51,098 MILES
Took car in for oil change. Before leaving the service dept, Traction Off/Service Traction displayed on message center. Service dept took it back again, 30 minutes later said message was off now but to bring it back if showed again. Before getting a mile from the dealership, service engine light came on. Took car back. They kept it for 5 days, said misfiring and excessive leakage, and replaced injector in #3 cylinder. 3 days later, service engine light came back on. Took it back for service again. Kept car for 2 weeks this time, replaced 3 intake valves and 2 exhaust valves. Have had car back for less than a week. When idling behind a stopped school bus car starting********, interior dash lights started going in and out, and knocking from front end. Pulled to side of road and turned car off. After waiting a few minutes I started it up again and it sounded normal. No service engine light yet. Drove on to work. When leaving work the service engine light came on so car is back at dealer for work once again, and they tell me they'll have to get "in-depth" to find out what's wrong. Any thoughts to what this ongoing problem may be are appreciated.
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Sunday, October 9th, 2011 AT 4:01 PM

1 Reply

Your car is still under warranty?
Document evrything about evrytime you take it in. Try taking it to another dealer.
Ask the service manager to look over, "Technical Service Bulletins" with you. See which ones might apply to your problems. Technical service bulletins are problems with a vehicle that do not have to be disclosed to the public unless asked for.

Here is one of a few I found;
2009 Chevrolet Cobalt Engine And Engine Cooling Service Bulletin 79049
NHTSA: Action Number: 10038727 Service Bulletin Number: 79049

Report Date:
Apr 01, 2011 Component:
Engine And Engine Cooling Summary: Gm: there are multiple warning lights on. There is harsh shifting, hard steering, and no start. There may be multiple trouble codes stored. *Rm

You can go to the NHSTA web site and really spend time to make sure you have them all but with just one or two under your belt, it will usually get things going.
Personally, I would ask them to show you the compression and leakdown test numbers for cylinders, especially number 3, as it sounds like it is not making compression or firing correctly. When your car is cool, check the ant-freeze to see if it has any brown contaminants in it or the overflow. Check engine oil to see if there are any milky deposits.
What kind of fluid was, "excessively leaking" from the front? With the misfiring and knockng it sounds like that cylinder is damaged and it might be from a bad head gasket. Also ask them for a cooling system pressure tests. Ask to see the specifications on both the compression and cooling systme tests to see if they are within spec.
I think they might have damaged your motor or the timing is off due to the timing be, ctankshaft and/or camshaft sensors ot other reasons.
Also, when you check your oil, take it under the light or sunlight and move the dipstick back and forth looking for specs of metal. That is an idication of a motor that needs a rebuild/
Don't mention that until the cylinder compression, leakdown and cooling sustem pressure tests are done.
For the compression test, the pressure should be no less than 100 PSI and the highest compression cylinder should be within 70% of the lowest compression cylinder.
The radiator cap should be marked with its max pressure. I do not have the amount of time a cylinder or the cooling system should hold these pressures, that veries and they should have a spec in the factory service manual that they can show you.
The oil pressure could be tested, if you do not have a gauge in the dash, which should be 50-80 PSI.
Start with the Service Bulletin and checking the NHTSA web site.
Then ask for tests and specifications.
Then if you find milky oil, brown or some other contaminated looking color in the raiator/overflow or metal in th eoil, confront them with that.
Ask to see the Factory service manual specifications for leakdown times, etc.
An educated, upset and tired of this !$#% Customer is just what they want to get rid of.

I hope this information helps.
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Sunday, October 9th, 2011 AT 5:07 PM

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