Knocking on cold start

Good morning,

Yes, there is a TSB on the noise, and I attached it at the bottom for you.

If you are under 70,000 in miles, it would be a warranty item.

Let us know if you have any other questions.

Roy

Hello, I just wanted to add to the concern you are experiencing. The knocking sound you hear is because a cylinder is misfiring. I would also recommend that you get the vehicle nice and hot from normal driving and let it sit overnight. In the morning remove all four spark plugs and inspect inside the bore for coolant. If there is evidence of coolant, then that's your cold start misfire causing that sound. You will also notice the expansion tank for the coolant getting low depending on how much of a leak there is.

I have done a few cylinder head gaskets for this particular concern. The intake manifold bulleting was updated. I believe it to include a misfire under load. The EGR passages are small holes and get plugged up causing a lean misfire to the adjacent cylinder. That would be my first step to inspect before spending money on the intake manifold. Please update us with that information.

Sounds like a plan.

Roy

First verify that is the EGR. Disconnect the electrical connector to the EGR. If the problem goes away, then there is an updated, I take an EGR pipe for the repair. If it still misfires with it disconnected under load, then you could have a bad coil or spark plug. Let us know what happens with the first test when you unplug the EGR. Posted a picture of the connector.

The cooler only has coolant running through it. I wouldn't worry about anything behind that going to the exhaust. If you remove the intake manifold, you will see the small EGR passages where the gases will flow. If they are plugged up, then the manifold and EGR pipe need to be replaced.

You can try to clean it but usually that carbon is pretty packed on there, that is why they had us just replace the manifold. To be honest I never had to replace one. It has been the head gasket failing causing that misfire on cold start. There is also a software update you can have done to see if it helps with the knocking sound and P0300.

Sounds like a plan.

Keep us updated on the result.

Roy

Can you post a video of it when it is knocking? I just feel like you are just installing parts on your vehicle. Also, I feel like you did not understand what to look for on the intake before replacing it? It seems like you are on the right track with the coils.

A misfire will slow the crank down and cause the rattle/knocking noise. A bad coil, spark plug, or injector can cause that. An engine mechanical fault can cause that also. If you post a video at least we can try to verify if the sound is due to a misfire or something separate from the misfire codes, you already have.

Thank you for the update. The pooling in the intake, do you mean the oil build up? Every CT has some oil in there from it taking in PCV fumes back in. As for the coil. I had a tech looking at a CT doing the same thing. Cold start rattle/knock.

We went in with a bore scope to look for coolant and it was dry. He orders an intake manifold and EGR pipe because of the bulletin without reading what the conditions for replacement should be. He installs it and the same cold start sound. He got lucky that in one of those starts the engine kept rattling around and we were able to look at the misfire counting up. We checked the coil, and it had no spark.

This business can throw curve balls at you at times. Will we ever see that condition again? I don't think so, but you may just be experiencing that yourself right now. If you swapped coils and plugs around and the misfire follows it, then you have already solved the issue.