1997 Oldsmobile Aurora Car wants to Run@225Degrees OR Highe

I've changed the Coolant w/a Better&Higher quality coolant & Replaced Therm( 180 degrees)-But the was"Supposed work done on heads prior to Purchase-(Cadillac &Olds do NOT recommend)&Seems between Rough/UN-Even Idle&Sound of leaking gases that may indeed be a Head Gasket Leak)??Car runs slightly better-Especially on Hwy-But IN Town IF I stop to allow to Idle,Car will JUMP from 195 to 225+ In Less than Minute&can go HIGHER IF allowed to idle any longer-(I.E. close to 250 degrees!).Could a "Head Gasket Sealant/repair kit/additive work in Meantime??OR;Does car basically need NEW Complete Heads to Fix Problem??Know this IS a Constant problem w/4.0Litre N-Stars w/NO Grill&NO Method to get cool air upon engine-Could "Hood Scoops OR Louvers be a poss. Fix to get cool, air to alum. engine??Its construct has NO Way for air to get to engine Stock-Hence my Idea of placing Small/conservative hood scoops on said car-OR do a Cold Air Induction Plumbed to frnt.Spoiler going to throttle body-would that be enough??
I am a PERM.Disabled Person for last 20+Years ongoing&Likely for Life&Need Help Plz!.:)
Thx.K.C.Moll 702-234-2457

updated 7/24/09

Car question is RE;'97 Olds Aurora,Vin-C,4.0Liter w/constant wanting to run HOT-(I.E. 225 to even 235 Degrees-w/Alum.Block&heads-Not good..Flushed/changed T-Stat,Only minor changes noticed?Car Has"NO Grille Space per-say&Needs method of getting AIR into engine bay"!Any Suggestions-OR Seen this problem Before?Other Aurora Forums seem to have LOTS of'over-heat type problems'BUT Mainly the '95/'96 Models&supposedly fixed by MY '97 Model-seems they jumped the gun as it is NOT"Fixed"in the slightest?I'm Perm Disabled-so is a Limit to what I can Physically do-But
How can I Locate problem&Fix?Could it be leaking heads?Only'rough running IS@Idle-rest IS-"OK".?Plugs/wires/temp sensor??Appreciate any Direction to anyone that might be of help!:)Thx.C.M.