Loud sound coming from engine at speeds over 45. Sounds like downshifting, but it’s not.

I would check to see if the exhaust is loose somewhere.

Steve

@tsolo thanks, I’ll check that out. I wondered if it was the ac compressor because I just got the ac running. I don’t think it was doing this when the ac was not operational.

Check the inside of your metal engine hatch cover for evidence of contact  from the compressor or alternator pulleys. They are perhaps rubbing on the hatch.

Larry

Yes, it is possible that the compressor is making that noise. Pull the compressor clutch wire off and take a drive. That will easily confirm whether that is your problem or not

Larry

Thanks Larry, @If-tp2511