Clanging sound
 

92 that I recently bought and just got to the point of being able to test drive it. PO said that it had a bad torque converter, but I have doubts about his mechanical and diagnostic capabilities.

I had just changed the engine oil and filter (proper fill level) and passively flushed the (filthy) tranny fluid.

When first started, fired right up and settled to a nice idle. Blipping the throttle resulted in a faint knocking noise. (I was inside the car so couldn't localize the noise.) Volume was about equivalent to a mildly sticking HLA.

During the test drive, the noise was about the same to start until I reached the end of our little road (<15MPH) and entered the highway (50MPH). Tranny wouldn't shift into higher gears (3rd/4th), so engine rpm was pretty high (5000-5500rpm) at 40-45MPH that I compromised on.

Suddenly, knocking noise increased dramatically and I pulled over to check things out. Knocking was pronounced at idle, and felt to be coming from beneath the intake's second runner on the engine's left (driver) side; listening was less definitive.

Limped back home at a walking pace. The sound I heard had a sheet-metal quality to it: A slight ringing to it, and a frequency that suggested something not very thick. The knock virtually disappeared during no-load conditions, but reappeared with either power or coasting. (Rather like a rod small-end/wrist-pin failure.) Engine stalled on me once, but started right back up without a problem.

We were just getting hit by a storm front, so I didn't poke around the car in the rain once I got home.

My first thought was flexplate, possibly just loosened bolts or maybe cracked. But the threads I have looked at don't seem to match when the noise occurs.

Any suggestions? Where is the inspection hole to access the flexplate/TC bolts?

Edit: And, oh, I forgot - the noise is not in synch with road speed, and does not seem quite in synch with engine speed. While creeping along, when I would slowly release the throttle the impression I got was the knock's frequency would decrease from a couple times per second to virtually zero on "no-load" and then pick back up again if on overrun/coast.

Re: Clanging sound
 

It's common for the engine to " tick" a bit if not driven for a few days. It's just caused by the oil draining after sitting. That tick should disappear in a minute or two.

Does your SVX still have the heat shields on the exhaust? They are a good source of mystery metallic noise. The sounds change too as the torque on the exhaust changes and as it heats & cools.

Re: Clanging sound
 

I am very familiar with Subaru HLA ticking. My 88 XT daily driver sounded like it was going to throw a rod when I bought it because it had sat for a few months. (I have a small herd of HLA equipped Subarus.)

The volume of this noise is considerable (not a mild to moderate tick), and sounds rotational in nature (i.e. - consistent interval between noises, roughly engine speed related, no harsh resonances). It does still have its heat shields, but the the volume and quality of the noise tells me it isn't something light like a heat shield.