RPM after serpentine belt change

[clearbluewater]

I was hearing squeeking sounds from engine, after changing belt sounds are gone, took it for test drive, it seems to be running ok. New belt is 10mm (1cm) shorter than old one. This was because of feedback from other owners.

The rpm gauge seems to misreporting, showing 5k, 6k when its not. Engine sounds fine. As I kept driving the rpm would get close to normalizing but not fully.

After 2 hours I noticed rpm starting to show accurate reading, based on throttle, engine sounds. But not sure if it's fixed.

Before I go out again I wanted to check if this is normal as it is a new belt? Any adjustments needed?

 

[alldodge]

The belt has nothing to do with the Tach and so long as the tensioner is working correctly their are no adjustments

 

[ESGWheel]

It’s not unusual for tachs to go a little wonkery as they age. What typically happens is the 4/6/8 selector switch on the back of the tach gets a little corrosion under it and causes it to misread.

My suggestion: get behind the tach if you can with a flashlight and find that little sliding switch. Then slide it back and forth a few times leaving it in the proper position and will be good for a while. It might be the type you turn and may need a small screwdriver. If you have do to this multiple times per season, time for a new tach.