1997 Pontiac Bonneville Problems

What owners report

Owners of this model year most often report engine coolant problems, largely tied to the plastic upper intake manifold and its gaskets on the 3.8L V6: coolant leaks, overheating and, in some cases, coolant entering the engine. Electrical complaints about sudden stalling or total power loss and steering complaints about loss of power assist when turning left also appear repeatedly, mostly in the 60,000-130,000 mile range.

1. 1
   Engine cooling

   Coolant leak / failure of plastic upper intake manifold

   • 17 complaints (12%)
   • median 98,774 mi at 7.3 yrs old (12 state mileage)
   • 2 mention a crash, fire or injury
   • owner-quoted repair $1,100 (median of 6 quotes)
   • filed 1999–2009

   Complaints describe coolant disappearing or leaking, overheating and, in some cases, a hole, crack or warp in the plastic upper intake manifold or its gaskets. Owners report that coolant reached the cylinders, sometimes stalling or locking the engine, and several mention replacing the manifold, gaskets or engine itself. Some owners say dealers or mechanics attributed the pattern to the plastic intake design used on the 3.8L V6. Reported mostly between roughly 50,000 and 130,000 miles, often while driving at speed or shortly after a coolant repair.

   2 related service bulletins

   What to check: Have a shop pressure-test the cooling system and inspect the upper intake manifold and gaskets for coolant residue or warping; ask whether the manifold or gaskets have already been replaced and keep an eye on coolant level.

   2 excerpts from owner complaints in NHTSA records

   “The intake manifold or the plemium whatever you want to call the thing wore out and all of my engine coolant went into the fuel cylinders and locked my motor down I was headed to macon ga from douglas,ga going to the hospital were they had transfered my brother and here I am in perry,ga broke down because Pontiac puts a plastic intake manifold on a motor I feel like Pontiac should have to pay for this part being replaced. …”

   NHTSA complaint #10067614, filed 2004-04, 128,123 miles

   “A block from home our engine shut down. The upper manifold had a hole in it due to the manifold being plastic, and crystalizing over a period of time. It cost us $729.00 to get it fixed. Luckily our engine wasn't hot or we would have had more serious problems.”

   NHTSA complaint #10037097, filed 2003-09, 113,000 miles
2. 2
   Electrical system

   Engine stalls or loses all power while driving

   • 24 complaints (16%)
   • median 110,000 mi at 8.0 yrs old (10 state mileage)
   • 1 mention a crash, fire or injury
   • filed 1997–2015

   Complaints describe the engine shutting off without warning at various speeds or while idling, sometimes taking steering and brake power with it, and sometimes restarting right away or only after sitting. A few owners link it to battery terminal or cable problems, with acid leaking and cables working loose, and one suspects the ignition switch. Dealers are described as unable to reproduce or diagnose the fault, with several reporting no stored codes. Reported across a wide mileage range, from around 39,000 to over 230,000 miles, with several complaints at 100,000 miles or more.

   3 related service bulletins

   What to check: Inspect battery terminals and cables for corrosion or looseness and ask whether the ignition switch or crank sensor has been replaced; if the car has a history of random shutdowns, get the fault codes and electrical connections checked before buying.

   2 excerpts from owner complaints in NHTSA records

   “The car lost all power while driving on several occasions. It would just quit and I would have no brakes or steering and all gauges would shut down. Sometimes it would lose power and then it would come back on while I was still driving cutting in and out repeatedly. It happened a lot when I was idling at a corner and then would start through the intersection. It would quit going through the intersection. Sometimes it wouldn't start after driving it a short distance. …”

   NHTSA complaint #10576488, filed 2014-04, 118,515 miles

   “While my wife was driving home with our children the vehicle suddenly shut off. My wife was able to safely pull off the highway and contacted me. When I arrived I found the positive battery terminal fell off the delco battery, causing acid to leak into the battery tray and front frame section. I replaced battery and had to repair the cable end because the end was seized.”

   NHTSA complaint #755665, filed 2001-12
3. 3
   Steering

   Power steering assist lost when turning left

   • 13 complaints (9%)
   • median 118,515 mi at 7.7 yrs old (7 state mileage, few)
   • filed 2000–2014

   Owners describe a popping noise followed by loss of power steering when turning left, while right turns still have assist; in some cases the wheel becomes very hard to turn in either direction. Complaints say the dealer or manufacturer did not resolve it, and several note that other Pontiac models with similar rack-and-pinion steering were covered by a recall while this model was not. Mostly reported between about 70,000 and 130,000 miles, sometimes at low speed and sometimes while driving.

   What to check: Test both left and right turns at parking-lot speed for unequal effort or noise, and check the rack-and-pinion and steering gear mounting bolts for leaks or looseness; ask for any steering repair records.

   2 excerpts from owner complaints in NHTSA records

   “1997 Pontiac Bonneville rack& pinion steering the power steering suddenly failed when turning to the left only. Turning right was still functioning with power assist. The problem increased over a short period of time to where the car wouldn't turn left at all (even manually). Complaint was made to dealership as well as manufacturer with absolutlely no resolution.”

   NHTSA complaint #10065876, filed 2004-04, 69,845 miles

   “While making a left hand turn vehicle lost power steering. Consumer had to use force to turn steering wheel. Dealership was notified, but did not resolve the problem. The consumer notified the manufacturer who stated that there was no recall on the vehicle but there were recalls on other models with the same rack and pinion. The consumer was told that his vehicle was not produced at the plant of the recalled cars.”

   NHTSA complaint #10081638, filed 2004-08, 100,000 miles
4. 4
   Brakes

   Brake pedal feel and hydraulic brake faults

   • 5 complaints (3%)
   • median 44,000 mi at 9.9 yrs old (1 states mileage, few)
   • filed 1997–2006

   Owners describe a hard or low brake pedal, grinding noises, and in some cases brakes that stopped working, with master cylinder or rotor and pad replacement. One complaint describes corroded hydraulic brake lines leaking fluid at several connections. Reported from very low mileage up to about 44,000 miles, with some complaints filed when the car was relatively new.

   1 related service bulletin

   What to check: Check brake pedal firmness and look for fluid weeping or corrosion at the brake lines and master cylinder; ask when the pads, rotors and fluid were last replaced.

   2 excerpts from owner complaints in NHTSA records

   “The problem started with a thumping sound coming from the front/brake area of the vehicle. After attempting to pull out of the shopping center I realized my brakes were gone. My husband was able to get it to rapid motors the next day and we were told that the master cylinder would have to be replaced. Just over 1 year later the same problems started again and again the brakes went out and we were told again a new master cylinder would need replacing. Each replacement has cost us a little over $300.00. …”

   NHTSA complaint #718770, filed 2000-02

   “Consumer heard a metal to metal grinding noise. Went to dealer where they replaced rotors/pads to front wheels. Dealer stated the brake rotors on the outside surface were blackened from heat and the brake pads were glazed.”

   NHTSA complaint #819695, filed 1997-12

Buying note. This model year draws repeated coolant and intake-manifold complaints, so a cooling-system pressure test and repair history are worth having before purchase. Also check steering effort in both directions, battery cable condition and brake line corrosion, since those are the other frequently reported problem areas.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.