I HAVE A 2008 CTS SEDAN (3.6) THAT HAS A SLIGHT PINGING NOISE WHEN SHIFTING BETWEEN GEARS AT NORMAL SPEEDS. HAD A 3 STAGE DE-CARBON TREATMENT DONE RECENTLY AT A CADDY DEALERSHIP. I HAVE ONLY USED SHELL 89 OCTAINE FOR THE LAST 6 MONTHS. I CAN ONLY HEAR THIS NOISE WHEN THE WINDOWS ARE UP AND THE BLOWER OR FAN IS SET ON LOW. I AM CONCERNED, PLEASE OFFER SUGGESTIONS.
Country: United StatesMake: CadillacModel: CTSYear: 2008Engine: 3.6
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I would suggest trying a higher octane fuel (91 preferable) and see if that helps. I had a Caddy in the shop a couple months ago with the same condition and suggested to the customer to use a higher (91) and he has had good luck with it. You can also try an octane booster you can get from an auto parts store.
have used shell super -v on occaison. i thought this car was designed to run on regular.
What is the 8th digit of your VIN?
The 8th didget is the number 7
If your vehicle has the 3.6L V6 engine (VIN Code V), use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, you might notice an audible knocking noise when you drive, commonly referred to as spark knock. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, the engine needs service.
If your vehicle has the 3.6L V6 engine (VIN Code 7), use regular unleaded gasoline with a posted octane rating of 87 or higher. For best performance or trailer towing, you could choose to use middle grade 89 octane unleaded gasoline. If the octane rating is less than 87, you might notice an audible knocking noise when you drive, commonly referred to as spark knock. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, the engine needs service.
Like I said, I used 89 octaine on a regular basis and 93 octaine on occasion. I don't believe it's a hard knock but rather a slight ping. You don't believe it is a timing issue or a sensor?
It could be a timing issue if the wrong oil is being used. The cam phasers that adjust the timing are hydraulically controlled with the engines oil. Sometimes, if the cam phasers are not operating correctly, it will set a DTC (diagnostic trouble code).
You should be using Mobil1 fully synthetic 5w-30 engine oil
The right oil is being used. I have taken this car to the dealership twice to deal with this problem and they have not isolated it due to the fact no diagnostic code is being thrown. Any suggestions?
I would actually take it back to the dealer and have them call TAC (Technical Assistance Center). I know for certain that they have case loads of concerns like yours. Not to dog your dealer, but they should have done this during your 2nd if not 1st visit. This is not only to help the technician with the diagnosis of this condition, but to ensure you as a customer that they are doing everything possible to resolve this issue. You, as the customer, have done all the necessary steps on your behalf ( using premium fuel and premium oil).
16 years GM Tech, ASE Master Certified