I've started traveling a bunch for my job so I'm looking for a "Road Car" and Bonneville is one of four cars I'm thinking about.

My 03 SLE was a great car. Bought it new and sold it 3 years old with 34k miles. My grandmother owns it now and it barely has over 40k on it! It did have the standard intake problem that all newer GM cars seem to have (fixed under warranty) but otherwise it was a great car that returned 30mpg on the highway.

If I get another Bonne I'm thinking about a GXP. I've heard many horror stories over the years about Northstars in Caddys. It seems they are either excellent engines or total junk in the shop constantly. I've driven several Northstars in Caddys and loved them but never owned one. If I buy a GXP, I want it to be low miles (30k or less).

Are there things I should look out for or look at when buying a used GXP?

Does the GXP get decent highway mileage?

Can I burn regular fuel or does it need premium?

Any advice you could give for GXP shopping would be great.

Thanks

I've had my GXP for just under 2.5 years now. Personally, I really enjoy the car. It'* a wonderful highway vehicle, very comfortable. It would be very similar to your previous Bonneville in this respect. I've found the V8 has lots of power to pass when needed. The GXP only requires regular gas, although personally I burn mid-grade. I'm getting about 23MPG highway. Can't tell you about city, never really paid attention. If I like a car, I don't really worry about fuel economy too much. There are a few things I've come across problem wise.

Many of the other 2K+ Bonneville issues are not resolved in the GXP. This includes things such as the poor adherance of the door water deflectors leading to water leaks, the intermediate steering shaft, electronic compass module and horn.

If we're talking specifics about the GXP, there are also a few...

- The foglight wiring harness is a known problem. There is a TSB out for this.
- Some reports of coolant leaks.
- A particular beef of mine is the engine oil cooler hoses.
- Transmission cooler lines.

I had some fairly significant transmission problems when I first got the car, but I haven't heard of this being common. I've had no trouble since it was serviced. They recently found my oil pan is weeping. I did have a problem with the timing cover leaking. The harmonic balancer was scored and they had to replace it, the seal and the timing cover.

I've really had no issues with the engine from a mechanical or electrical standpoint, just some leaks. A mechanic friend of mine always says "If it didn't leak, it wouldn't be a GM". He also continues to say "... but at least they always start!". He owns four GM'* so he can't be very turned off by the problems.

The GXP has its moments of frustration, but I'd buy another one (at least I say that now... ask again in another 100,000km).

I drove a 3.8L Impala for a few years and got 28-29mpg w/ regular. My GXP gets 21mpg following the same route using premium. If I'm real careful, I can get 23mpg on the highway. So, don't have high expectations on the mileage.

At 15,000/yr & assuming $2.50/gal for premium, I figure a penalty of $550/year in gas expenses.


I understand you can run regular (or mid-grade), but there should be some loss in performance and mpg.
Again assuming $2.50 vs $2.30 (premium vs regular), premium gas needs to get you about a 1.8mpg improvement in fuel economy for break even.

I've had some of the common problems, plus a wheel bearing and heat seater.

Would I buy another... probably not. Besides, in a couple years, it'll be tough to find one with lower miles.

But I'm not giving it up either. It'* a LOT of car! And a Love/Hate relationship. It beats the heck out of my wife'* CTS.

My GXP is in the for sale section

Thanks for starting this thread... the info in the thread plus the little stuff i found thanks to google is showing me all green lights on this purchase.. I'm not worried about the MPG b/c my fiancé works about 5 mins from the house and she can take the GXP to work while i drive the 16miles up the interstate in the 2003 Grandprix SE....... I'm heading to the credit union in the morning!!!

Quess my PM didnt scare you away......ROFL!

lol... Naaa

I think I have the record for GXP gas mileage. After a night of nitrousing light to light.

LOLOL!!!! U'd think u were drivin an old skool guzzler.

haha that'* still much better than what my dad'* pick up that I use for work gets. '96 F250, probably about 8 city mpg, or maybe even less now considering it'* age.