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'12 Boss low rpm engine rattle

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I have a 12 Boss with 9k on the engine. During some spirited driving, not near readline, flashing yellow check engine icon came on for about 10 seconds, then went off. And stayed off. I drove it home because the light stayed off, about 10 miles. Now, there is a low rpm knock in the engine. Engine runs fine otherwise, and NO lights come up. I'd considered maybe carbon buildup, though not likely, then I wondered about bad gas. Kinda afraid to drive it. At this point it's just speculation. Try some isopropyl in the fuel and add some new fuel on top of it ? Any help would be appreciated . Don.
 

TMSBOSS

Spending my pension on car parts and track fees.
7,530
5,247
Exp. Type
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Illinois
Re: '12 Boss low rpm engine knocking

Fuel related "Ping" is not common at idle or low loads.
Does the noise go away at higher RPMs?
There TSBs which may covering your tapping noise

Late Model Restoration lists all TSBs for mustangs. Here is a link.

https://lmr.com/products/2012-Mustang-TSB-Recall

The following may apply. Checkout their site for more details.

Ford TSB Article # 11-9-15

Ford TSB Article # 12-8-14
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
Re: '12 Boss low rpm engine knocking

12Boss302 said:
"I have a 12 Boss with 9k on the engine.

Now, there is a low rpm knock in the engine."

Hi Don:

Can you explain this in a bit more detail? Big difference between "Knock" and Ticking Sound or Ping.

Let us know if the noise is audible at idle and/or what is the RPM range If audible at idle only, you should be able to discern a tick noise v. a knock noise.

Check the oil level first.

Then, if you do believe it is a knock (deeper, heavier note noise), and it is audible at idle and continues up to say 1,500 to 2,500 RPM's, or so, then call your Dealer and seek their advice. They should send out a tow truck as you should not operate the engine with a knock noise.

Carbon build up and pinging will only happen while accelerating under load, (in gear as opposed to revving the engine in neutral).

Engine Ticking Noise (per TSB), is explained in the appropriate TSB. (Note: The flashing yellow CEL you mentioned is a concern and not usually associated with the TSB Tick issue.)

Good luck and keep us posted,

302 Hi Pro
 
Re: '12 Boss low rpm engine knocking

Do you have track key?
Do you have a scanner tool to check for engine codes even tho light is out?
Is your car tuned?
Being that its a 2012 your power train is still covered by Ford.
If your answer to those questions above is No. Take it in to your service dealer.
If yes to some questions return to stock. Take it in to your service dealer.
Bottom line is you need to report it. This way if they claim that they found nothing and something does happen you will have a record of reporting this knock. It will make having any repair work or at the extreme an engine replacement that much easier.
If you say nothing you will receive nothing!
 
Re: '12 Boss low rpm engine knocking

superhero said:
Do you have track key?
Do you have a scanner tool to check for engine codes even tho light is out?
Is your car tuned?
Being that its a 2012 your power train is still covered by Ford.
If your answer to those questions above is No. Take it in to your service dealer.
If yes to some questions return to stock. Take it in to your service dealer.
Bottom line is you need to report it. This way if they claim that they found nothing and something does happen you will have a record of reporting this knock. It will make having any repair work or at the extreme an engine replacement that much easier.
If you say nothing you will receive nothing!

Thanks for the suggestions. The engine starts, idles, and sounds normal, until 2000rpm and up. I guess it's more of a rattle. Oil is fine, and it occurs with both keys. I'm not a mechanic, but I have a hunch. I emailed a form with VIN and mileage info, back to Ford and asked for a recommendation of a Preferred dealer in my area. I will trailer it there and let them start it and listen to it.
 
Re: '12 Boss low rpm engine knocking

12Boss302 said:
I have a 12 Boss with 9k on the engine. During some spirited driving, not near readline, flashing yellow check engine icon came on for about 10 seconds, then went off. And stayed off. I drove it home because the light stayed off, about 10 miles. Now, there is a low rpm knock in the engine. Engine runs fine otherwise, and NO lights come up. I'd considered maybe carbon buildup, though not likely, then I wondered about bad gas. Kinda afraid to drive it. At this point it's just speculation. Try some isopropyl in the fuel and add some new fuel on top of it ? Any help would be appreciated . Don.

UPDATE. Flatbedded the Boss to the dealer last Wed. Saturday the dealer called and said Ford is sending a new engine, covered by the 5 year powertrain warranty. No info yet on the failure. I'll update at completion of the job. Needless to say, I am seriously relieved.
 
Re: '12 Boss low rpm engine knocking

Well that's a bummer but Ford has been great about standing behind their product. Maybe we should start a thread for those that have had engines replaced to see if there is any consistent reason as to what is failing.
 
Re: '12 Boss low rpm engine knocking

VooDooBOSS said:
Well that's a bummer but Ford has been great about standing behind their product. Maybe we should start a thread for those that have had engines replaced to see if there is any consistent reason as to what is failing.
That is a Great Idea! You will recieve a LIKE!
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
441
Southeast
Re: '12 Boss low rpm engine knocking

12Boss302 said:
Still waiting on engine at the dealer. Out of curiosity, besides the 'normal' Boss-specific external parts on the engine, are there any more 'subtle' external identifiers that would indicate a Boss engine, and not, say, a 'normal' Coyote engine ? I don't know if I could tell the difference. Thanks.

I'm sure it has a specific P/N for a Boss application. Your Dealer used your VIN to order your parts to get them right.

Check with your Advisor and get the part number they ordered.

My Boss has a circled letter "B" (blue paint), in the engine valley, but that might be an assembly line ID marker.

Good luck with your repairs,
302 Hi Pro
 
Re: '12 Boss low rpm engine knocking

12Boss302 said:
UPDATE. Flatbedded the Boss to the dealer last Wed. Saturday the dealer called and said Ford is sending a new engine, covered by the 5 year powertrain warranty. No info yet on the failure. I'll update at completion of the job. Needless to say, I am seriously relieved.

Ford replaced the engine under the power train warranty. I am very happy to get the car back. The story does end well in this case . Merry Christmas to me !
 
Re: '12 Boss low rpm engine knocking

12Boss302 said:
UPDATE. Flatbedded the Boss to the dealer last Wed. Saturday the dealer called and said Ford is sending a new engine, covered by the 5 year powertrain warranty. No info yet on the failure. I'll update at completion of the job. Needless to say, I am seriously relieved.

Glad to hear you were taken care of. My 12 Boss exhibited a similar noise in the low 2K rpm range AND was consuming oil. I too received a new engine. Valve train problem perhaps?
 

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