I have a 1991 subaru loyale, 1.8L engine w/ 4wd. It started with a cold start in -10 degrees f. My engine turned over a little rough but this was normal for cold starting. It has been making lifter noise all winter but always went away when the engine was at normal operating temp. After starting on the particular day the temp dropped, however, it was making more noise than usual. Unfortunately i thought this was possibly another lifter making noise due to the abnormal temp. However, it never went away, even after warming up. I let it sit and restarted a day later to try and figure out where exactly the noise is coming from. I am afraid to drive my car or even start it again. It seems the whole engine is making a metal to metal chattering. Sounds very valve train sounding for sure, but could be making crank noise too. (Its hard to tell, it is loud.) The engine still runs like normal as far as running. It runs and idels smooth, and seems no loss of power. The oil pressure has lowered a little, but not significantly since all went bad. Could the oil pump have given out? Could an oil channel have plugged. I am baffeled. I am sure with the noise internal damage is being done everytime that thing runs. I am not driving it, for I can guarentee it won't go far before dying completely. The car ran fine the night before, no probs. ANY HELP OR SUGGESTIONS. I am thinking the engine will have to come out for overhaul but don't know for sure. Anything you can suggest please let me know. Thanks a bunch.