After a long period of consideration, I've decided to keep my Bonneville GXP and will try to make the best of it. I've become attached to this car. The coolant no longer leaks after the sealing tablet treatment, so hopefully it's not the water pump housing like the stealership suspected it. While reading about the GXP and the Northstar, apparently GM uses some kind of quick disconnect hoses that leak a bit by default so maybe it's just a design thing.

Long story short, I would like to replace some (if not all) of the coolant and vacuum hoses in this engine. I found a kit for the Bonneville SSEi;

https://hpsimotorsports.com/collections ... -1998-2003

But considering the obvious design differences, I'm not sure if it will be compatible. Apparently this same place sells silicone hoses by the foot, but not having a shop manual for the GXP I have no idea as to the lengths.

Does anyone know if there is a ready-made hose kit specifically for the GXP? And if not, does anyone know where I can find a diagram with the hose connections, or at least the diameters and lengths needed?

The Northstar is a completely different engine, not even in the same ballpark as the 3800. It doesn't have the vacuum lines running all over like the 3800 does. It has vacuum leaks most likely caused by the 90° elbow inside the intake plenum, the intake boot and the intake gaskets themselves.

Lot of good pics here: https://www.cadillacforums.com/threads/ ... ps.171319/

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Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 55k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 95k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 260k | Official Bonneville Hauler

Yeah I was going to say, I looked at the engine and while there are some hoses and lines, it looked nothing like the 3800. At least it's not like some cars where there are vacuum lines running under the interior trim of the car, but I was kind of hoping there was a kit at least to make things easier. This car's tough. I'm already dreading the day I have to change the spark plugs because of the position of the cylinders near the firewall.

Do you have any idea where the GM techs could've connected their tool to check the pressure in the coolant system? I started getting the vacuum leak after that inspection and without a clear understanding of what this car is, I have no idea what could've happened. I drove the Bonneville for almost 2 months and nothing came up but now that stupid MIL lights up every 3-4 days. I kept clearing it thinking it was a one-off but after the 5th or 6th time I can't think that anymore.

They would have used the coolant reservoir cap to pressurize the system. They probably didn't do anything, just a a coincidence. Use some carb cleaner and spray around the left and right sides of the intake plenum and you should be able to find the leak pretty easy. You're just watching for a change in idle.

What are your codes?

_________________
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 55k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 95k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 260k | Official Bonneville Hauler

My OBDII scanner is picking up two codes, but they are identical. p0446, and p0446 P. I have no idea what the "p" part means and googling yielded zero answers. I have been fiddling with my car, the coolant is no longer dripping after I put in 2 more stopleak tablets, but I've noticed it does horribly on gas. 3 quarters of a tank only got me 258km, Which is 160.5mi. I've also noticed some staining on the driveway that's in the rear wheel area, quite a big one too.

I'm thinking there's a leak in the fuel line, which would rob me of my gas and cause a vacuum leak. Does that make sense? I've ordered a PF 2100 K&N fuel filter, but now I don't know whether I should get the NAPA fuel line repair kit or an entire fuel line/return line, which I found over here, https://www.linestogo.com/pontiac-bonne ... 1-a2g-set/
It seems fairly self explanatory but I don't know if this is the problem really. I mean something's leaking gas, something is causing a vacuum leak code, and something is robbing quite a bit of power from the engine. I'm just assuming that it's the fuel line and fuel filter. I mean 160.5mi on 3 quarters of a tank of gas, something is definitely wrong here.

P = Powertrain.
B = Body.
C = Chassis.
U = the vehicle's computer/harness/network.

As to P0446;
P0440 is an EVAP system code, specifically related to the system not being able to vent itself. There are three main components (there are others, but these are the main culprits), 1) your gas cap 2) the purge solenoid and 3) the EVAP cannister itself.

Just as much as the system wants to maintain a vacuum, and allow for a pre-determined decay rate (otherwise you'd set P0442), it also needs the ability to vent itself when too much vacuum is present. If the purge solenoid isn't working, or the canister vent isn't working or the canister itself is plugged, these can result in P0440. My first bet though, check your gas cap. Did you just recently fuel? 9 times out of 10, any EVAP code is a gas cap related code as rarely do purge solenoids or EVAP canisters go south. If it was, and there is truly no fault, the code will most likely clear itself after 3 consecutive successful operating cycles.

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Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck