Here's the scenario leading up to the problem. Took the car out on a sunday and drove it moderately hard. (just enough to both excite and **** off the wife) Drove it the last 30 minutes on the freeway while heading home with no sign of trouble. Parked it until morning and when it was started the next day it made a loud noise (maybe a metal on metal clank, again I'm taking the wife's description here) Then it seemed to run fine. Once I got the car that afternoon the engine light was FLASHING, so I took it in. There was some lifter like noise coming from under the hood.
After the dealer looked at it, they told me it had a bent intake valve. They also told me that the spark plug on that cyclinder had a broken/cracked cermic insulator. The part has been repaired but, now the lifters seem to rattle when stepping on the accelerator at low speeds, especially in 3 or D.
First. What damage may have occured to the engine as a result of the cracked spark plug? Could this have caused a premature detonation in that cylinder, thus causing the bent shaft? Should I be supspicious about damage to the cylinder wall due to a fractured piece of the sparkplug falling in to it? (and the dealer not telling me?)
Second. Could the noise I'm now hearing be due to the improper/poor reassembly by the dealer? Am I looking at another major procedure to get the lifter noise corrected? It's a 2002 w/ CA emissions

Thank You,
Mike Clark

 

What year?

 

This car came for CA so I assume it has CA emissions.

 

Shouldn't be making any noise if they fixed it right. Take it back and complain.

Detonation caused the spark insulator to break, which then got caught between the piston and valve on the up stroke causing the damage. Do you run premium gas?

You can do a compression test on the cyliner to see if there is any wall, piston, or valve damage.

 

all 2002 are CA Emission, It shouldn't be making any noise. Did they do an oil change after they took your engine apart? Do you have enough oil in the engine? IF everything checks out, then you should take it back and complain. And you meant "Bent Valve" right? not shaft?

 

Yes I meant bent valve. Thanks for the info.

Mike

 

If you have a bent valve, a little trip to the dealer won't fix it. You need to have the head removed and have the valve replaced. If it's bent, it might not retract all the way into the head, thus leaving a space inbetween the hydraulic lifter/valve stem. Thus causing the tapping noise.

And Mark, I'm from Seattle.

 

Hasn't it been reported by someone that the 3.5 VQ can loose a screw from the intake (at the throttle body) which could cause damage inside the engine? Could this be another case?

 

YOU READ MY MIND!!!!

Dealer is feeding you BS, another infamous throttle-body screw injestion.

Remove the bellows infront of your TB and make sure you have TWO screws still.

 

Which screws is it that fall out, the 2 in the main throttle plate or the ones in the intake runners?

 

the main throttle plate.

 

Great...is there any effective method of securing them to prevent this? loctite?

 

I'd say locktite would work, if I had a 2K2+, I'd definitely remove them and locktite them since it can't hurt.

 

Any updates?

 

Funny as I'm reading this just now, scrolling down I was already going- throttle plate screw musta fell out. I was the 1st one to report this to the .ORG a few years ago, when I got 2 free 3.5L engines cause of it. Electrode got smacked by the screws rattleing around inside the engine, which destroyed the plug, then it tried to escape the combustion chamber through the exhaust valve. The valve only opens a few milimeters and there is no way anything the size of a screw like that will get through the open valve. I just repleaced my friends throttle body (3.5L with no warranty no more) and we loctite the screws before putting on the TB. FYI new TB when it crapps out is 1200 bux new... man I'm glad I have a 3.0L.

 

Got me worried now, will have to check mine and locklite them in.

Pedro