5-30 oil is fine.. the argument about synthetic and conventional oils goes on endlessly on here .. its make me laugh constantly
just use a decent motorcraft or wix filter.... pure one is fine... change your oil at 3K or so with conventional and 5-7K on syn and you should be fine....
it is hard to imagine your sound... but if it is more noticeable in the car when you rev it that would sound like an exhaust leak... you said they put flowmasters on... i would say they need to check again..
did you hear this noise before they did that or after?
always start with the obvious first
heavy weight oils in high mileage motors is OLD SCHOOL... auto zone, advance, pep boys the whole retail chain will employ anyone so just ignore them unless you know the guy... overhead cam motors in general have major issues with heavy oils.. but speaking for the mod motor crowd its totally bogus in your climate... no reason to do it....
your car doesnt burn much oil i bet... these motos last a long time ...
2006 LX with HPPBlue, Light Camel Interior,Magnaflow Exhaust,PI Zip Tube
Underdrives from ADTR.net
Pioneer AVIC X930BT Nav system, JL xD400/4amp, JL Speakers, Audiovox backup camera
Given to DG in Ohio
2013 Ford Expedition Limited EL, Pearl White
2000 HPP RESURECTION RIP 8/17/2012 died in Dayton OH