Thread: My new (old) 2001 Grand Prix GT

This is my 2001 Grand Prix GT. I bought it for my wife in 2003, then we sold it to a neighbor in 2010. Just recently the neighbor decided to get a newer vehicle, as the Grand Prix needed some work to get past California's emissions test, and she offered it back to me. I accepted, and started this car's road to recovery. While new to this forum, I'm a long-time member and gearhead over at pontiacbonnevilleclub.com, where I owned a 1997 Bonneville SE from 1999 until my wife totaled it one year ago, so I've had more than a little experience with the L36 engine. My wife and I have collectively owned five Pontiacs in total.

Here's the Grand Prix GT with my wife showing it off the day we got it back in 2003:


Here it is in 2005 after I got the rear windows tinted:


and here it is just before I got it back, in August 2016. (I changed out the tails for aftermarkets back around 2009 after the originals delaminated):


and right after I got it home:


after its first good exterior wash:


Since then, there is an enormous list of work I've done and had done to the car to get it up to where it is now. I just wanted to get a formal "Hello" out there. I already know some of you from my years at the Bonneville club.

Nice looking blue car! Like meeting an old friend.


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Originally Posted by cheatah faheatah

Sooooo envious of Cali cars...rust &rot free...

Yeah, it is absolutely rust-free. It's super-clean underneath. I'll put together a list of all the work I've done on it since I got it back. It's gone through quite a transformation. I don't have any plans to top-swap it or anything, but after 15 years it had a number of things that needed to be addressed. I'm pretty proud of how far it's come.

Mechanical repairs:

Car had a P0410 DTC for Secondary Air Injection Reaction Pump system.
-Pump was dead. Replaced pump. Drilled a 1/4” hole in the bottom of the rubber shield to allow any water intrusion to drain away.
-Pump was missing the intake filter screen. Replaced with one from a salvage yard.
-Performed TSB #04-06-04-037: repositioned intake hose to prevent sucking in water.

-Relay to Secondary Air Injection Reaction pump was dead. Replaced relay.
-30 amp fuse in fuse block had melted the fuse block around that fuse. Replaced fuse block with one from salvage yard, and installed new fuse.

-Replaced the Secondary Air exhaust manifold check valve because it was the only part left of the Secondary Air circuit, and why not?

Car had a P1404 DTC for EGR closed position performance.
-Replaced with an EGR from a salvage yard. Problem continued to occur.
-Replaced with a new EGR. Problem continued to occur.
-Took car to dealer and had TSB #01-06-04-018A performed: Reprogram PCM with new calibration tables for EGR valve. Problem has no longer occurred.

Car had a Traction Control light on, and Magnasteer was obviously not working.
-Replaced the EBCM with one from a salvage yard. Magnasteer restored, Traction Control light out.

Fuel lines were leaking at connectors to fuel rails.
-Replaced all fuel lines and fuel filter all the way back to the tank with new.

Upper intake was leaking oil around the gasket.
-Replaced upper intake and gasket with new.

Water Pump was leaking.
-Replaced water pump with new. Replaced coolant bypass elbows with new aluminum elbows.

Oil pan was leaking. Transmission pan was leaking. Drivetrain was making a chirping noise.
-Dropped the oil pan, inspected lower engine. (It looked great.) Installed new oil pan gasket, reinstalled oil pan, changed oil and filter.
-Replaced harmonic balancer.
-Dropped subframe. Inspected torque converter. Found torque converter was wrong model (The neighbor I sold the car to had a transmission rebuild shortly after I sold it to her.)
-Replaced torque converter with correct new converter.
-Replaced lower control arms with new arms.
-Changed transmission fluid, filter, & gasket.
-Replaced lower engine mount and transmission mount with new.

Car’s original struts were completely shot.
-Replaced all struts and springs with a gently used (5000 miles) set from a ClubGP member with Vogtland springs and KYB AGX adjustable struts.
-Replaced front and rear sway bar end links with new Moog end link kits.
-Installed front and rear shock-tower bars sourced from salvage yard from a Monte Carlo and a Buick Century, using Don Rome brackets.

Car’s tires were shot.
-Replaced with Goodyear Triple-Treds and an alignment.

Air filter was dirty and housing clamp clips were missing.
-Replaced air filter with new, replaced clamp clips with clips sourced from salvage yard.

Interior & Exterior repairs:

-Had the rear window tint re-done.

Car had passenger floor water leak.
-Verified weatherstrip had fallen into blower housing. Replaced weatherstrip, but also installed new deflector part #15794785, and installed cabin air filter because why not?

Driver’s door weatherstrip was torn.
-Replaced with weatherstrip sourced from salvage yard.

Passenger sideview mirror mount was broken.
-Replaced sideview mirror assembly with one sourced from salvage yard.

Driver’s seat support mesh was shattered.
-Sourced a good-condition passenger seat from salvage yard, cannibalized it for the support mesh and foam seat cushion and rebuilt the driver’s seat.

Trunk lift struts were shot.
-Replaced with new.

Wiper blades were shot.
-Replaced with new Bosch 22A and 22B blades.

Driver’s A-pillar plastic trim was broken.
-Replaced with trim sourced from salvage yard.

Driver’s sun visor w/electric lit mirror had badly torn fabric.
-Replaced with one sourced from eBay.

Interior carpet was torn.
-Replaced with a carpet sourced from a salvage yard & given a good power wash.


Center console cupholder module was broken.
-Replaced with module sourced from salvage yard.

Shifter had torn boot.
-Replaced shifter assembly with one sourced from salvage yard.

Blower fan knob broke.
-Replaced with new sourced from eBay.

Rear spoiler had problems. It had one or two mounting bolts that broke off inside it and rattled around whenever I opened or closed the trunk lid.
-Removed spoiler, cut a hole around 2” in diameter in the underside of it with a hole-saw and fished out the broken parts and vacuumed out the crud that was rattling around inside it. Re-mounted the spoiler with new bolts to replace the broken ones, and added nylon spacers to allow a slight space beneath the spoiler so debris can be washed away.

OEM OnStar antenna was broken.
-I could have just removed the whole thing, but I like to keep the look original even though the analog OnStar service is obsolete, so I sourced a used antenna from eBay and replaced it, just because.

All of the door interior trim panels had broken nylon barbed fasteners and cracked trim strips along the top by the window.
-I restored each trim panel with new nylon fasteners and replaced the broken trim strips with Trim Gard #22L-01 edge trim.


One of the headlights had a cracked plastic mounting bracket.
-I repaired it with epoxy and reinstalled.

Rear deck trim padding was rotted.
-Replaced with new foam padding.


And of course on top of all of that, I cleaned the heck out of *everything*. I had the entire interior out of the car and cleaned everything. I used magic-erasers and leather restoring gel on all the leather interior surfaces.

I have a couple lingering problems I’m shooting down.
-Lots of plastic rattles inside. Center console & steering wheel buttons are particularly noisy.

-One of the pulleys in the engine is screeching after driving for around a half hour. I think it’s the water pump I recently had replaced. Next week it will be replaced again under warranty, but I may have the tensioner assembly replaced at the same time just to rule out future age-related problems from it, and a new belt.

-The rear door driver-side door lock is not working with the remote or the buttons inside the car. But then it briefly did work today with both the remote and the buttons, so I’ll have to troubleshoot the wiring. I just hate taking the door trim panels off, because each time some of the nylon fasteners get all torn up.

-When I had the front door trim panels off, I replaced the factory Bose speakers with aftermarket Infinity’s, but everyone knows aftermarket speakers sound quiet with the factory amp because of the extreme low impedance of the OEM Bose speakers. I have plans to tap the wires to the Bose amp and hook up an aftermarket amp. I won’t start that project until I get the last engine issues ironed out.

-Once everything is done, I’ll think about paint. The replacement passenger sideview mirror housing is painted black rather than blue, and the rear bumper and spoiler need painting, and frankly the whole car could use a refresh on paint. I haven’t decided if I’ll do some paint work myself or just have a shop respray the entire car.

Other than the pulley squealing, the car is running and driving great. The AGX struts are a touch stiff, so I might dial them down. The Triple-Treds and the shock tower bars and new lower control arms and sway bar endlinks and motor mounts have everything nice and tight. The car handles like it’s on rails. With almost 208,000 miles, it's in really good shape now, and makes a nice spare car for us. If it doesn't get wrecked in the next five years, my eldest son will get to drive it. It's a decent project car for now.

Originally Posted by cheatah faheatah

DAMN, sounds like you could have built a car from the ground up easier, lol

Yeah, it really pays off to maintain a car well, compared to resurrecting a car that has been somewhat neglected. To her credit, the neighbor I'd sold it to had the oil changed regularly and did get the transmission rebuilt, and had the brakes serviced as needed. Shortly before replacing the car she had some repairs done that included a new Driver Information Center and a new windshield. The car had decent bones and I knew it hadn't been mechanically abused. She put a lot of miles on it in both local driving and long trips, and frequently hauled around two Siberian husky dogs. There was a *LOT* of dog fur throughout the interior. When I pulled the seats and center console out to replace the carpet it gave me a good opportunity to clean everything really well. Other than leaks throughout the drivetrain, worn struts, lower control arm bushings and ball joints and motor mounts, the car was pretty solid. Absolutely *no* rust.

For what I've spent on it, I could have bought a used car that needed some work. But one nice thing going into this project is that you have some idea what the possible upper limits will be if you're not going to wildly mod the car. In a worst case scenario you'll need an engine and a transaxle, and these drivetrains are the opposite of rare. My local Pick-N-Pull was the source for many specific parts that I needed, and compatible cars were plentiful. I did much of the work myself and had my local mechanic perform anything I didn't have the time or inclination to do. So long as the car doesn't get wrecked, it should last a very long time, and that was my main motivation in taking the car back. I knew the car's history and knew I could work with it. I have a lot of confidence in my ability to maintain it, having owned a Series II L36 Bonneville for 16 years.

I don't *need* an extra car, but having one gives me some flexibility in maintaining our other two primary vehicles. My daily driver since the wife totaled my Bonneville a year ago is now a 2005 Mercedes S500, and my wife's daily driver is a 2011 Chrysler Town & Country minivan. The van recently needed a 4-wheel brake job again (these vans eat brakes). My wife and I have opposite work schedules so we each need a car, and she works every other weekend (she's a nightshift nurse), so I often have to pay a shop to repair her van while I'm at work or else I have to take a day off work to do it myself. With a spare car I was able to do the brake job in spare time over a couple days. Same with working on the Grand Prix itself. My 9 and 11 year old boys helped me out with power-washing the carpet, vacuuming, and replacing the strut assemblies and motor mounts. Everyone should own a small child who can scamper up into the trunk to slip the nuts onto the top of the rear strut assemblies when you're changing those out!

Originally Posted by Bugsi

-One of the pulleys in the engine is screeching after driving for around a half hour. I think it’s the water pump I recently had replaced. Next week it will be replaced again under warranty, but I may have the tensioner assembly replaced at the same time just to rule out future age-related problems from it, and a new belt.

In hunting down the squealing noise I had the water pump, tensioner assembly, and belt replaced, with no change. Had the power steering pump replaced, still no change. Finally located the problem with help from this forum and pontiacbonnevilleclub.com, where after posting a video of the noise, people from both sites recommended checking the PCV valve. I discovered the PCV valve was *completely missing*. $3.27 later, the problem appears to be fixed. The missing PCV valve may have played a role in the P1404 DTC I was getting, that complained about the EGR closed position performance. I'd already had a dealer reprogram the PCM with updated EGR tables, but in hindsight the problem was probably the missing PCV valve.