1999 Buick Lesabre Problems

What owners report

Complaints about this model year center on the 3.8L V6's plastic intake manifold and plenum, which owners describe leaking coolant into the engine and leading to hard starting, stalling, or misfires, often without warning. Fuel smells and leaks from the lines and pressure regulator show up next, and older cars in the sample also report rusted-through brake lines that failed suddenly. Electrical complaints, particularly with the ignition switch and security system, account for a further share.

1. 1
   Engine cooling

   Coolant leaking from intake manifold/plenum

   • 34 complaints (16%)
   • median 80,000 mi at 5.8 yrs old (21 state mileage)
   • 2 mention a crash, fire or injury
   • owner-quoted repair $800 (median of 5 quotes)
   • filed 2000–2015

   Owners describe coolant disappearing from the reservoir, white smoke or antifreeze burning in the engine, a check engine light, and eventually a car that cranks but will not start because coolant has entered the cylinders. Several report the plastic intake plenum or upper manifold gaskets as the source and had the manifold, gaskets, spark plugs and sometimes coolant-soaked components replaced; one describes the problem returning years later. Some complaints say the engine was ruined and needed replacement. Mostly reported between roughly 20,000 and 100,000 miles, often noticed after the car is parked or on short drives.

   1 related service bulletin

   What to check: Check the coolant level and look for crusty residue or a sweet smell around the intake manifold and throttle body; ask whether the intake manifold and gaskets have been replaced and whether coolant has ever been found in the oil.

   2 excerpts from owner complaints in NHTSA records

   “My car is a 1999 Buick la sabre with a 3.8l engine. July/20/2012 my car had 80,000 miles on it when my engine started to miss. When I got it looked at by my friend I was told there was coolant in the cylinders. The engine had problems with the intake plenum leaking coolant, because of the EGR system. He then fixed the car. On november 20, 2014 my engine had 138,000 miles when it overheated on the highway. I found no coolant in the reservoir with coolant in the oil. …”

   NHTSA complaint #10663342, filed 2014-12, 80,000 miles

   “While driving 25 MPH the engine light illuminated then the vehicle stalled. The dealership was notified but did not resolve the problem. The vehicle stalled because of a cracked plenum which allowed water to enter the engine. The dealer replaced the plenum, spark plugs, cleaned lower intake and cleaned the coolant from the cylinders.”

   NHTSA complaint #10075461, filed 2004-06, 84,896 miles
2. 2
   Fuel system

   Fuel odor and fuel leaks

   • 44 complaints (21%)
   • median 60,005 mi at 6.5 yrs old (23 state mileage)
   • 20 mention a crash, fire or injury
   • filed 2001–2019

   Owners report a strong gasoline smell when starting, stopping, accelerating, or after parking, and in some cases visible fuel spraying or leaking from lines or the pressure regulator. Repairs described include replacing fuel lines, the fuel pump, and the pressure regulator. Some complaints note a fuel-system recall on this model and say they had a leak before receiving any notice, or that a replaced part was not covered. Reported from about 44,000 to 170,000 miles, with several cases under 60,000 miles.

   Recall 04V0900001 related service bulletin

   What to check: Smell around the engine bay and under the rear of the car after startup, look for damp or stained fuel lines, and ask whether recall 04V090000 (fuel pressure regulator) was completed.

   2 excerpts from owner complaints in NHTSA records

   “A very bad gasoline odor was noticed when starting and stopping the car. The shop discovered two (2) leaks in the gas line. The meter, pump and lines had to be replaced. I don't know if the shop still has the parts and I certainly did not want them.”

   NHTSA complaint #10126536, filed 2005-06, 76,939 miles

   “The car would occasionally smell like gas during acceleration. It also skipped frequently when going up hill. I was driving down the street when the car stalled. I pulled to the side of the road and the engine compartment erupted in flames. The car was a total loss. It was only after the fire that we discovered that there was a fuel system recall in sept. 2004. I bought the car from a GM dealer in oct. 2004 and never received a recall notice nor was I made aware that there was such a problem with this model.”

   NHTSA complaint #10161522, filed 2006-07, 88,000 miles
3. 3
   Electrical system

   Stalling or no-start from ignition switch and security

   • 24 complaints (11%)
   • median 82,500 mi at 9.2 yrs old (16 state mileage)
   • 3 mention a crash, fire or injury
   • filed 1999–2019

   Owners describe the engine quitting while driving or refusing to restart, sometimes with the security light on, dash lights coming on, the speedometer jumping, or doors unlocking on their own. Dealers and shops in these complaints replaced the ignition switch, the theft-deterrent module, the ignition cylinder and key, or repaired battery cables; some repairs did not end the stalling. Spread from about 48,000 to 190,000 miles, often recurring over months.

   1 related service bulletin

   What to check: Ask whether the ignition switch, ignition cylinder, or theft-deterrent module has been replaced, and test that the car restarts reliably after sitting and that the security light behaves normally.

   2 excerpts from owner complaints in NHTSA records

   “Battery went down when clock left on because ignition was loose or faulty. So now I make sure clock is off when I shut it down. Car started up fine - drove it 6 miles - came back out to start it after an hour and nothing-no sound nothing-about 20 minutes later I tried it again and it started right up. There has been a grinding sound n cassette player with no cassette in it at one time. Dash lights lit up while driving so automatically thought there is short in dash board. …”

   NHTSA complaint #10633247, filed 2014-09, 187,000 miles

   “Traveling about 65 - 70 MPH I noticed my speedometer went 'wacky', meaning it went down to 0 - 20 MPH and back up again to the speed I was traveling. Nothing else happened. The next time, maybe a week to a couple weeks later it did I it again, only I heard the doors unlock and it had died. Since then it has been happening more frequently. I have always been able to start it right back up. I can be out on the highway or in town. I usually put it into neutral, start it and keep going. …”

   NHTSA complaint #10637715, filed 2014-09, 190,000 miles
4. 4
   Brakes

   Rusted brake lines with sudden loss of braking

   • 12 complaints (6%)
   • median 96,353 mi at 8.8 yrs old (10 state mileage)
   • 3 mention a crash, fire or injury
   • filed 1999–2014

   Complaints describe metal brake lines rusting through until the pedal goes to the floor, the brake warning light comes on, and stopping power drops sharply; drivers report using the parking brake or low gear to stop. In several cases the lines were replaced in full after inspection, and some owners found the lines badly rusted before any leak appeared. Typically reported above roughly 70,000 miles, and most often past 120,000 miles on older cars.

   What to check: Have a shop inspect the steel brake lines along the frame and above the rear axle for rust and seepage, and ask whether any lines have been replaced.

   2 excerpts from owner complaints in NHTSA records

   “There were no events leading to the failure. The failure was sudden in nature. The failure was the brakes on my car which resulted in a minor (no damage) accident due to lack of stopping power. The brake lines rusted through (pictures available, the lines may still be available) causing nearly complete loss of stopping power. I was able to pull over but did run into shrubbery resulting in minor scratches to the exterior. …”

   NHTSA complaint #10414639, filed 2011-07, 130,000 miles

   “The brake lines in my 1999 Buick Lesabre have completely rusted through. I was driving home, under normal weather and road conditions, when my brake system light went on. Upon pulling over, I saw a large leak in the brake lines. I managed to get home and upon further inspection, saw all lines were extremely rusted. I will be replacing all brake lines in the car with new ones myself, as it is too costly to do at a shop. The car has 143304 miles and is not old.”

   NHTSA complaint #10269462, filed 2009-05, 143,304 miles
5. 5
   Air bags

   Airbag deploying or horn sounding without a crash

   • 8 complaints (4%)
   • median 100,000 mi at 16.3 yrs old (5 state mileage, few)
   • 3 mention a crash, fire or injury
   • filed 2000–2018

   Complaints describe the horn blowing on its own and the driver airbag deploying while parked or at a steady speed with no impact, in one case injuring the driver's hands. Owners link the two symptoms, describing the airbag inflating inside the steering wheel and pressing the horn contacts; some report the airbag or sensor needed replacement and that a manufacturer case was opened. Reported from about 58,000 to 205,000 miles, with several cases on cars that sit in hot sun.

   What to check: Check whether the horn works normally and does not sound on its own, note any airbag or SRS warning light, and ask whether the airbag, horn contacts, or clockspring have been serviced.

   2 excerpts from owner complaints in NHTSA records

   “I was sitting at a red light when my air bag from the steering column deployed in my face. I did not hit anything. It was on or about 1/25/18. About a week prior to this event my horn began to steadily blow inexplicably. I did not have any reason to suspect anything other than a malfunctioning horn so I disconnected the wires to the horn. When the air bag deployed about a week later I concluded the air bag was inflating inside the steering wheel applying pressure to the horn sensor. …”

   NHTSA complaint #11074558, filed 2018-02, 205,000 miles

   “Air bag design flaw - a life threatening design flaw. I am the original owner of a 1999 Buick Lesabre custom (purchased at the end of the model year). The car often spends time in the bright florida sun. Although I use a reflective windshield sun screen, the car still gets hot inside (as do most florida cars). Recently, the horn began to honk continuously. I took it into the orange Buick and gmc dealer in orlando fl. The problem is that the air bag has swolen up and compressed the horn relay. The air bag is broken and needs to be replaced. …”

   NHTSA complaint #10062638, filed 2004-03, 47,500 miles

Buying note. On a car this age, the intake manifold and coolant system, the condition of the steel brake lines, and whether the fuel-pressure-regulator recall was done are the things most worth verifying before purchase. A pre-purchase inspection that includes the brake lines and a cold-start check will tell you more than service records alone.

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.