1987 Porsche 911 — windshield replacement created a highway whistle

Intermittent stuff lies if you only catch it once. A pressure test beats staring at a dry driveway if the 1987 Porsche 911 is losing coolant with no puddle. Save the big job until that test fails. On “windshield replacement created a highway whistle,” that was the fork that mattered for me. Just my two cents from doing this recently. This is the filter I use when the thread starts repeating itself. If that fails I'll eat the diagnostic fee.

I wouldn't throw parts yet. Move a coil or plug on the 1987 Porsche 911 if it's cylinder-specific and see whether the code follows. Don't erase codes until someone who can help has seen them. No need to make it theatrical. Your commute and mine probably aren't the same, but the test still applies. I refuse to clear codes until someone else sees them.

I'd want a measurement, not a hunch. Loaded-suspension checks on the 1987 Porsche 911 catch play that a wheels-hanging inspection misses. You'll know quickly if you're on the wrong tree. That's the sequence I'd use. I'd sleep better after that step, even if it finds nothing. No warning lights, which is why I'm documenting it.

This is usually cheaper to test than to guess. Get a real battery/charging test on the 1987 Porsche 911, not just resting voltage, before blaming a module. Don't erase codes until someone who can help has seen them. Verbal 'we'll take care of it' is not a plan. Parking it somewhere I can hear it better next time.