Hello,

I am new to the board and looking at purchasing a Deville between 1996 and up. I was wondering if They run on 93 octane or 87? Also I was wondering what kind of gas mileage thet get. Let me know, interested in buying one.

Brian

 

I have recently purchased a 1996 DeVille with 92000 miles. It takes Premium and I am getting about 19 mpg by driving around town and to work. Very little highway driving. I have read somewhere that you can run 89 octane, but you will lose some performance. After I bought the deVille, I changed out the spark plugs, fuel filter, and pcv valve, just to freshen it up a bit.

Good luck in your search

 

if I run 89, will it damage the engine at all or just loose performance?

 

I can't say for sure. Maybe someone else on this forum can answer this.

 

Search "octane"

https://www.cadillacforum.com/search...mitbutton=+OK+

 

HELLO, I HAD A 96 DEVILLE CONCOURS AND IT RAN PERFECTLY FINE ON 87 OCTANE, I TRIED SEVERAL TIMES TO SEE IF THERE WAS ANY DIFFERENCE USING THE 91 OCTANE OR THE 87 OCTANE, THE ONLY DIFFERENCE I NOTICED WAS IN THE PRICE OF THE FUEL.THIS DEVILLE HAD 168000 MILES ON IT WHEN I TRADED IT LAST WEEK, I PERSONALLY DROVE IT FOR THE LAST90000 OF THOSE MILES . IT WAS VERYEASY ON FUEL IN MY OPINION,(16-17 MPG AROUND TOWN AND USUALLY ABOUT 22-24 MPG ON THE ROAD) I STILL DRIVE A 95 SLS AND I USE 87 OCTANE IN IT AS WELL, IT IS EVEN BETTER ON FUEL THAN THE DEVILLE WAS,(18-19MPG CITY AND 23-26 MPG HWY.) NOW FOR THE GAS HOG, I JUST PURCHASED A 04 ESV AND IT SEEMS TO GET ABOUT 12 MPG CITY AND 17MPG HWY!!!! NOT BAD FOR A 5700 LB. VEHICLE. I HAVE OWNED SEVERAL LUXURY CARS IN THE PAST ,MB'S /BMW'S AND THE LIKE, I'LL TAKE GOOD" OLE FASHIONED DETROIT IRON" ANY DAY!!!!

 

there are other factors but long storie short it's what the wallet can bear on this one i have a 91 Deville.

 

octane has much more to do with knocking / pinging (pre-ignition) than hp (power).

GM Engineers suggest that is is OK to run an lowest octane that engine will
handle w/o knocking / pinging.

i got dual tanks on my 4x4, one tank i always fill with REG, the other
sometimes i fill with PREMIUM if towing or heavy loads are involved
as i expect to push the throttle to its widest and command the engine's full
power climbing hills & mountains or pushing a head wind. when the need is
there, i flip the switch to the PREMIUM and as soon as the need stops,
flipt it back to the REG.

however, it is your car and your cash .. so i leave that decission to each owner.
i met enough drivers than havent a clue what pinging or knocking is that its scary
to tell them how they can choose if they cant tell when they should..

i'll put something in the FAQ on the subject.



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Personally I wouldn't use 87 octane in the Northstar. Cadillac recommends minimum 91 for a reason. I have no idea how much more premiumand higher octanes are in the USA but here in Canada it is about 8 to 10 cents.