My 04 Forester developed a VERY high frequency low volume scream under the hood after a recent 300 mile run through cold/icey roads. It has not abated since. It is electrical in nature as it will subside somewhat when I challenge the electrical system (such as press door locks).
I can hear it when the engine is off, key out. Low volume but very high pitch. Definetly coming from the engine. Diffiuclt to pinpoint due to the frequency.
Check engine light is not on. 137K miles. Running about 700-800 miles per week. Most of that is at highway speeds: 50-70 mph.
No other symptons. Runs fine.
Any ideas?