Mechanical noise when starting engine

your egr circuit is clogged. how many miles on her? you must act quickly, to avoid possible blown head gasket

 

there is a circuit. watch @NutzAboutBolts youtube

 

Pipe, EGR valve, EGR cooler(most important), intake manifold, there are holes that clog.
I use a brass bore brush in a drill and gunk to clean them out.
Pressure washer and oven cleaner for the cooler, gunk, carb or brake cleaner for the valve.

 

I had the same on my 2010. Turned out to be a very small head gasket leak. Happened when the car had been sitting for awhile was a loud kind of knocking.

 

yep, get on it before she blows

 

Other than cleaning of EGR, I would check for miss fire codes, spark plugs, and coil packs just to keep an close eye on possible head gasket leak...

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Dont know if someone mentioned, but keep an eye on coolant level.
If you are adding coolant and see no leaks from hoses etc, then could be headgasket leak into the cylinder.

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Get Good OBD2 scanner like CARISTA + Dr. Prius android Apps. You will know much better the cause of problems. But it is indeed true, you need to check your EGR valve at around 100k miles and clean it if you are handy enough. Otherwise just remove 2 bolts on the EGR module (black cylinder), pop it out and try to push it if it is sticky or not. Rotate it fully and close it right away without any slack, otherwise EGR valve stuck opened and cause stalling. I checked mine at 100k miles and it was still smooth so I will wait for about 40k more miles to clean the whole intake manifolds, EGR, new PCV valves, and coolant at the same time.

 

The idea is to clean the egr circuit BEFORE you had a problem... not after...
Like changing the oil/filter, coolants, brake fluid BEFORE they fail and cause huge expensive problems.....

 

Yeah don't wait. 100k is about the longest you want to go, for a full initial cleaning. Don't set yourself up to procrastinate, by piling OTHER chores on to do at the same time. OP's 298K miles is alarming, needs immediate attention.

Do the full EGR circuit clean out, including the intake manifold (pay particular attention to small EGR capillary passages, one per port, on the intake).

If you want to change the PCV valve it's cheap, or at least clean it with carb cleaner. If the plugs aren't due leave them alone. With some care, the full EGR cleaning can be done without spilling a drop of coolant.

Look into oil catch can too.

I can post some boiler plate info, links and repair manual excerpts in a bit.

 

EGR circuit INCLUDES the intake manifold.......
Because.....
There are holes/ports for each cylinder that the exhaust gas' get sucked into the cylinders....
Extremely easy to clean with a gun bore brush and gunk.

 

We got a pair of stainless steel drinking straw cleaning brushes (if you use such straws you NEED such brushes...), and one I immediately requisitioned for the garage. They're a perfect fit for intake manifold EGR capillaries. Start it in, slip carb cleaner straw in beside it, give a shot, then run the brush in. Repeat as needed.

 

I think some only clean the egr cooler, tube, and valve, and forget about the manifold.
And still have a problem.

 

I used my hand brush the first time I cleaned it. But as I was searching for something else, I came
across my bore brush, and realized that using this would be a LOT easier and faster and less messy!
I used either brake or carb cleaner on the first port, but it dried up too fast. That's why I used gunk.
Less than 10 seconds with the drill moving in and out, and it was clean.

Any type of brass brush will work though. A steel brush could damage the port walls. Brass is softer.

 

My description was maybe confusing: the stainless steel drinking straw brushes have nylon bristles.

 

I just did an EGR cleaning. Will compile the video later. It will be a series of work comprising of EGR cooler, EGR pipe, intake manifold, throttle body, coolant, PCV, oil catch can and MAF. Took me 2 and a half day to finish it mostly due to spending time to take the videos (playing with lighting, camera angles and batteries).

Do it all at once. Save a lot of time and the car is now super smooth.

 

Okay, the "stainless STEEL" kinda threw me off....