Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 1996 Pontiac Bonneville owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owns a 1996 Pontiac Bonneville. The contact stated that several attempts had to be made before succeeding in starting vehicle. The vehicle was taken to a mechanic where the failure was located at the intake manifold and oxygen sensor. The intake manifold cap was melting and causing oil to spill. In addition, the failure was producing white smoke from the tailpipe exhaust. The vehicle was repaired but the contact was unsure as to the exact repairs made to the vehicle. The contact also stated that the anti-theft system failed and would alert the contact that the doors were opened, and the seat belts were not secured erroneously. The fuel injection system was also defective and was repaired by replacing the fuel injector, and adding fuel cleaner. …
On 02/18/2002, 04:20 am, my wife went to start the car to let it warm up before going to work. Upon start up, there was an explosion and there was a fire instantly. I ran out and rolled the car out of the carport and into the back yard. The neighbor came running with a fire extingusher and put out the fire just before the fire department arrived. There was a recall (your number 96V116000). The upper intake manafold did fracture from one end to the other...gapping open about two and a half inches.. My car was repaired for this recall on 01/19/1998. I guess that this was not a fix for the problem. The GM investigater looked at the car and told me "that there was nothing that we had done to cause this problem". He would not say anymore. On 02/18/2002, the prrson for GM called and said that they would not accept any liability for the problem. …
Car was at aproximately 87000. Turned the car on, there was a loud explosion and smoke came out from under the hood, didnt see any flames, popped open the hood, and smoke just continued to pile out. Engine light came on, and the mechanic found the engine was on its last breath. Had engine relaced for a used engine with 4500 miles on it for $1500. Soon after the engine the alternator started to die, where just by standing next to the car you can hear metal to metal grinding noise coming from it. Paid $100 to get new alternator. Right after alternator the eg r valve died, had it replaced, another $300 spent. Now come spedometer saying 99000 but the second engine only having 60000 the serpentine belt cracked and worn out beyong believe. Another $75 spend. …
Around jan 2008 while driving a plastic water hose burst. I replaced it and had no other problem until around aug 2008. This time the water pump started leaking. I replaced that and the thermostat and radiator cap, but I still kept loosing coolant. Then I found a crack in the radiator which I replace around the end of aug 2008. I still kept having to top off the coolant reservoir ever two days. About June 2008 I started having trouble with the veh starting, it would seem like it wasn't getting enough gas or flooding. It would be running but barley and it would not accelerate when you press the gas pedal. Finally it would start. It doesn't do it all the time but it's doing it more often now. I've fuel system and injection cleaners with no change. Then I went to NHTSA and found a recall 96v-116 that seems to be the cause of my problem. …
Cooling system leakage-the black plastic cover on the intake manifold leaks coolant/water. It leaks when the weather is cold, it does this when ever parked and the car is allowed to sit and get cold. There is clear evidence it is leaking around the base of the plastic cover where it seals against the aluminum intake manifold. It has done this every winter for the past four winters. It is getting worse, and from the complaints I have read it is common to the 3.8 l engine. It does not leak at all in the summer or fall, only in the winter below 35 degree's. What is the real problem and is there a solid fix for this, or are all repairs just temporary until the new gaskets start leaking again? Is there any type of recourse or recall? The colder it gets, the bigger the leak and the puddle under the car. It also stinks when you drive it while the coolant cooks on the motor.
My 1996 Bonneville started acting up, roughly idling, and hesitating when taking off. There was loss of power, poor gas mileage, car would shut it self off while driving down the highway.check engine light came on and started flashing. Took it to auto zone to get it checked. Scanner idicated that it had multiple misfires, and that my map sensor was bad. Replaced map sensor. Still didnt change on how the vehicle operated. Replaced one of coil packs, still nothing. Put new plug wires and nothing cahned. New oxygen sensor installed, and still nothing. Changes. Over all I just got done spending $150.00 on this car and I cant even afford that, and still have not resolved the problem. I replaced basically everything that the computer came up with. What can I do here to solve this problem without me hurting my financial status, and me blowing the car up.
I bought this car in December of 1999, I beleive that the car was in an accident before I bought it, because the driver side door does not have the labels on the door for the weight or tire pressure, all it has is a parts number sticker a white lable. I have asked the Pontiac dealer about it and they said that some come with just that label. I payed $16.000 for the car and beleive that the car was in an accident prior to purchased date. I have had the paint peel off the hood shortly after buying it and now peeling on the roof over windsheild. But with the sticker off the door I belive that I was taken. I still owe $9.000 in payments. I also think that it was a lemon, because on the winsheild is a sticker that says sunset Pontiac satisfaction, a round sticker on the driver side of windsheild. I have never seen another sticker like this on any other vechicle.
The engine on this car failed. It has 115,000 miles. It was maintained from the start. We purchased it new. The intake manifold failed and leaked antifreeze throughout the motor. We had the manifolds, oxygen sensors, and catalytic converter replaced. We found out there was a TSB issued on this vehicle regarding the manifold problem. Pontiac and the dealership were contacted. They both told us it's a common problem, but they'll do nothing. I'd understand given the mileage that this is not a new car, however, knowing there's a TSB issued on it, it seems they are failing to provide a good product to their customers.
Tl contact owns a 1996 Pontiac Bonneville. While driving between 35-40 MPH, the vehicle gradually lost power and shut off. When the contact attempted to restart the vehicle, it backfired. The vehicle was pushed to the side of the road and towed to the dealer. The dealer stated that the upper intake manifold was cracked and would cost $503 to repair. The current mileage was 176,000 and failure mileage was 105,000. Updated 04/08/08. The battery was replaced due to the vehicle not starting.
Tl contact owns a 1996 Pontiac Bonneville. The vehicle backfired when the ignition was started, and the check engine indicator light illuminated. The intake manifold was damaged. This failure occurred twice before and the manifold was replaced. A local mechanic stated that this vehicle was included in recall # 96V116000. However, the manufacturer stated that the vehicle was excluded from the recall. The contact possessed the repair invoices. The current and failure mileages were 150,000.
NHTSA investigations
Engine compartment fires
Engine complaints in other Bonneville years
Frequently asked questions
How common are engine problems on the 1996 Pontiac Bonneville?
NHTSA has 44 complaints about the engine & cooling of the 1996 Pontiac Bonneville, 29% of the model year's 150 complaints. The component named most often is exhaust system › manifold/header/muffler/tail pipe (12 mentions).
Is there a recall for 1996 Pontiac Bonneville engine problems?
No. NHTSA lists no engine & cooling recall for the 1996 Pontiac Bonneville, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 1996 Pontiac Bonneville engine problems start?
Half of the complaints with a recorded mileage happened before about 105,000 miles, and 8% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 5 fires and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.