The 1999 Pontiac Montana has no open NHTSA recalls. Owners report 7 recurring issue clusters, led by “Intake manifold or gasket coolant leak and cracking.” Every Pontiac is now 15+ years old, which changes the maintenance question from 'what mileage?' to 'how old is it?' — hoses, belts, coolant, and brake fluid age out even on low-mile cars. The G6 uses GM's Oil Life System (change oil when the message appears, at most every 12 months) with Dex-Cool coolant and either the 2.4L Ecotec four or the 3.5/3.9L pushrod V6. Parts remain cheap and plentiful through GM's shared platforms — these cars are inexpensive to keep healthy if the age-based items aren't ignored.
No open recalls on file. NHTSA lists no unrepaired safety recalls for this year, make and model. A recall can be issued at any time, and a specific car can still have one open — check yours by VIN at nhtsa.gov/recalls.
What drivers and federal regulators have officially reported about the 1999 Pontiac Montana.
ENGINE AND ENGINE COOLING
69 NHTSA complaints · 2001-11 → 2012-06
“IN SEPTEMBER OF 2002 (~53000 MILES)WE NOTICED THAT THE LOW COOLANT LIGHT CAME ON”
“WHILE DRIVING 65 MPH THE INTAKE MANIFOLD GASKET FAILED AND ALLOWED COOLANT TO MIX WITH THE ENGINE OIL”
“MY 1999 PONTIAC MONTANA VAN'S INTAKE CRACKED AT BETWEEN 50,000 AND 60,000 MILES”
ENGINE AND ENGINE COOLING
7 NHTSA complaints · 2003-03 → 2007-10
“DURING A REGULAR OIL CHANGE MY MECHANIC DISCOVERED OIL IN THE ANTI-FREEZE”
“WHILE DRIVING APPROXIMATELY 40 MPH, THE VEHICLE BEGAN TO OVERHEAT”
“HEAD GASKET LEAKING ON 1999 PONTIAC MONTANA, 80,000 MILES, $700 TO REPAIR”
LATCHES/LOCKS/LINKAGES
17 NHTSA complaints · 2001-06 → 2008-01
“AUTOMATIC SLIDING DOOR ON PASSENGER DOOR OPENED BY ITSELF WHILE DRIVING AT 40MPH”
“RIGHT SLIDING DOOR OPENED WHILE DRIVING,AND ALL MECHANISMS WERE INOPERABLE”
“SLIDING DOOR WILL NOT CLOSE. WHILE DRIVING DOOR OPENS”
AIR BAGS
3 NHTSA complaints · 2002-05 → 2002-09
“WHILE DRIVING AT 20/35MPH CONSUMER WAS INVOLVED IN A HEAD ON COLLISON AND NONE OF THE AIR BAGS DEPLOYED, VEHICLE WAS TOTALLED”
“UPON IMPACT, BOTH DRIVER AND PASSENGER AIR BAGS DID NOT DEPLOY”
“AFTER BEING STRUCK HEAD ON, THE OTHER VEHICLE WAS GOING 35-40MPH AND THE AIRBAGS DID NOT OPEN”
POWER TRAIN
12 NHTSA complaints · 2001-08 → 2014-04
“THE TRANSMISSION REPEATEDLY SLAMS / HAMMERS INTO GEAR”
“INTERMITTENTLY TRANSMISSION WILL SHIFT VERY ROUGH AND HARD, AND TRANSMISSION EMITS A WHINING NOISE”
“WHILE DRIVING TRANSMISSION DOES NOT SHIFT PROPERLY IN COLD WEATHER”
SERVICE BRAKES, HYDRAULIC
5 NHTSA complaints · 2001-08 → 2004-03
“WHILE DRIVING DOWN A HILL APPROXIMATELY 45 MPH BRAKE PEDAL UNEXPECTEDLY FELL TO THE FLOOR, AND DRIVER WAS UNABLE TO ACTIVATE BRAKE SYSTEM”
“WHILE DRIVING, THE MASTER CYLINDER FAILED”
“WHILE PULLING INTO A PARKING PLACE AT 1-2 MPH CONSUMER APPLIED BRAKES, PEDAL WENT TO FLOOR”
AIR BAGS
14 NHTSA complaints · 2001-07 → 2014-04
“THE AIR BAG LIGHT STAYED ON”
“WHILE DRIVING 35 MPH SRS LIGHT APPEARED ON THE DASHBOARD AND REMAINED ON”
“WHEN I GET INTO MY MINIVAN AND START THE ENGINE, THE AIR BAG LIGHT COMES ON SOMETIMES”
Issues on other model years
Source: NHTSA Office of Defects Investigation (ODI). Complaint data refreshed Sep 20, 2026. Investigation data refreshed Sep 20, 2026.
We display NHTSA's record with attribution; we don't editorialize on what these complaints mean for any specific vehicle.
Critical for safety and preventing major damage
Change when the Oil Life System calls it, and at least every 12 months. On engines this age, many mechanics suggest a practical 5,000-mile ceiling — aging seals and PCV systems contaminate oil faster.
Estimated cost — typical U.S. ranges
Dealer
~$120–$160
Shop
~$85–$115
DIY
~$25–$55
Full synthetic costs more than conventional. 5-quart 0W-20 + filter is the typical bill.
Rotate every 7,500 miles. Check tire date codes too — sidewall age (6+ years) retires tires on old cars before tread wear does.
Estimated cost — typical U.S. ranges
Dealer
~$85
Shop
~$60
DIY
Free
Often free at the shop where you bought the tires — worth asking before paying.
Inspect pads, rotors, and especially brake hoses and hard lines at every service — line corrosion is a real failure mode on 15-year-old northern cars.
Estimated cost — typical U.S. ranges
Dealer
~$85
Shop
~$60
DIY
Free
Most shops do this free as a courtesy with any service. Don't pay separately if you can avoid it.
Replace every 2 years. Decade-old fluid is the hidden cause of soft pedals and seized calipers on aging GM sedans.
Estimated cost — typical U.S. ranges
Dealer
~$180–$200
Shop
~$125–$140
DIY
~$10–$25
DOT 3 or 4 — match the cap. Vacuum bleeders make this a one-person DIY.
Keeps your vehicle running smoothly and efficiently
Drain-and-fill every 45,000 miles with Dexron VI. On high-mile units that have never been serviced, prefer repeated drain-and-fills over a pressure flush.
Estimated cost — typical U.S. ranges
Dealer
~$330–$500
Shop
~$235–$355
DIY
~$60–$180
Some sealed transmissions have no dipstick — fill is precise and best left to a shop. Many drivers can still DIY drain-and-fill.
Iridium plugs at 100,000 miles on the G6's engines. Replace wires/boots on the pushrod V6 at the same time — they're brittle at this age.
Estimated cost — typical U.S. ranges
Dealer
~$285–$390
Shop
~$200–$275
DIY
~$25–$100
Iridium plugs cost more but last 100k+ miles. V6/V8 access varies wildly — some are tough.
At this age, replace the belt AND tensioner as a pair on any evidence of cracking or noise — a weak tensioner eats new belts.
Estimated cost — typical U.S. ranges
Dealer
~$195–$235
Shop
~$135–$165
DIY
~$20–$50
DIY-friendly if you can reach the tensioner. Inspect for cracks rather than swap on a strict mileage interval.
Replace every 30,000 miles — a cheap, 5-minute job on the G6.
Estimated cost — typical U.S. ranges
Dealer
~$60–$95
Shop
~$45–$70
DIY
~$15–$40
5-minute job on most cars; the airbox lid usually has clips, no tools needed.
Extends the life of your vehicle and improves comfort
Dex-Cool is rated 5 years / 150,000 miles — but on cars this old the interval is effectively 'every 5 years.' Check for intake and water-pump seepage while it's drained; use Dex-Cool only, never mixed with green coolant.
Estimated cost — typical U.S. ranges
Dealer
~$285–$330
Shop
~$200–$235
DIY
~$25–$60
Use the manufacturer-specified coolant — wrong color/chemistry can damage the cooling system.
Test the battery and alternator annually. Parasitic drains from aging body modules are common on this era of GM — a healthy battery masks them until it doesn't.
Estimated cost — typical U.S. ranges
Dealer
~$225–$390
Shop
~$160–$280
DIY
~$130–$250
Most auto-parts stores test and install batteries free with purchase. Skip the dealer markup.
Typical U.S. ranges. Actual quotes vary by shop, parts choice, and vehicle condition.
How we estimate: Dealer = OEM parts × 1.4 + labor × $165/hr. Shop = parts + labor × $115/hr. DIY = parts only.
This maintenance schedule for the 1999 Pontiac Montana reflects Pontiac's published service intervals and the GM Oil Life System system. Your actual service needs may vary based on driving conditions, climate, and vehicle usage. Always consult your owner's manual for model-specific recommendations.