99 GT that is making a grinding noise near the harmonic balancer

I have a 99 GT that is making a grinding noise near the harmonic balancer. It sounds like the timing chain is rubbing against the engine cover.

The sound seems to be coming from the area around the harmonic balancer.


Background: My check engine light came on 2 months prior with intermittent P0300 – 308 Random and specific cylinder misfires.
I used my ODBII reader to erase the codes only to have them reappear 2 weeks later. Problems continued and became more frequent.

I was blasting a WRX all the way home from work and as I pulled into my driveway I started hearing the noise but it was still very faint. The noise became louder and is now an obvious and loud noise that appears to be very serious. During the race I did not exceed 5K RPM


Here’s what I have done to diagnose the issue:

ACTION: Removed the belt and started engine to see if a belt driven component such as water pump was causing it.
RESULT: Engine still makes the noise so it is not belt driven.

ACTION: took off both valve covers and briefly started engine incase the noise may have been coming from heads (cam)
RESULT: The noise is not coming from the head nor is it coming from that general area.

Dees anyone have any experience with such a noise and maybe next steps in this diagnostics.


Miles on car : 120K
Modifications to the car: NOTE: None of these mods have been done recently
Cold Air
70mm Throttle body
X-Pipe w/Cats
Magnaflows
3.73’s
Pulleys

PS: If your suggestion is get a new car, I just bought a 03 Cobra
Thanks in advance for any info

Thanks for the advise. I am going to tear it appart tonight. I was going to do this last week but I was waiting to get an engine diagram so I know what the heck I am looking at.

Thanks

asthmaticZeater said:

well. its possible that your toothed timing gear has been damaged somehow. dont think ive ever heard of one being though.

it sits right inside the front cover, directly behind the crank pulley. it actually sits on the crank snout and turns. and a magnetic pickup in the side of the front cover uses it to tell the crank position and keep timing.

if it was damaged somehow, that could possibly cause the misfire code. its also located right where you say the noise is coming from. so this would be my first guess.

the only way i know of to check it would be to pull the front cover and examine it. not all that hard really. youll have to remove the PS pump (well unbolt it and tie it back), remove the crank and water pump pulleys, and your valve covers and front cover. once the front cover is off the ring will slide right off and you can go from there.

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