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 1998 Pontiac Trans Sport owners, lightly cleaned up (personal details are redacted by NHTSA).
A well maintained 1998 Pontiac transport with a 3.4 liter engine developed a coolant leak. This was diagnosed by a local service center. As they explained that my vehicle has an intake manifold leak, it was also mentioned that they have seen many manifold coolant leaks with this engine. I decided to have it repaired at a GM dealer where I purchased the vehicle. They also explained that they service many of these type of leaks. They explained that the repair calls for a new type of manifold gasket and new bolts. The mechanic even showed me where on the old gasket the failure usually occurs. Although it May seem as if these comments where anecdotal, it still appears to point to a general failure in the design of the manifold gasket. This repair was very expensive. Why haven't these 3.4 liter been recalled? Are only inexpensive manufacturer defects recalled? …
Diagnosed with intake manifold gasket failure on 1998 Pontiac Trans Sport with 3.4 v6 engine. Oil and antifreeze mixed and fixed by dealer at cost of $890. With no assistance from general motors. All to common problems on this engine and the 3.1 v6 with speculation that the dexcool antifreeze deteriates gasket. Could possibly be true since gasket is now made out of a diffrent material. At this time it is imperative that NHTSA forces general motors to recall these engines and reimburse all owners who have paid out of pocket for repairs. This vehicle in question was well maintained and items were changed way above recommended service schedule. Vehicle also developed a rough idle with no obvious cause with possible explanation of internal engine damage. These intake gasket failures could be the reason for numerous engine fires witnessed on the highway. Also I am the original owner. …
On 12/26/05 I smelled coolant when exiting my vehicle. After investigating, I found that coolant was leaking. I took it to a mechanic, and had the internal gasket replaced for $575. The next day I saw that it was still leaking coolant. I took it back, and had the water pump replaced for $166. The next day I saw it was still leaking, and I had no heat. I took it back to the mechanic, who told me that it is leaking at the timing cover, and the lack of heat could be due to an air bubble, or I May need my heater core replaced. He gave me rough estimates of $900-$1500 for the leak, and probably about $400-600 if my heater core needs replaced. GM needs to recall this vehicle for this problem.
My 1998 Pontiac Trans Sport minivan has developed a problem where the dexcool coolant is leaking into the engine...my mechanic found coolant in the engine oil. I called my dealer, the man from whom I bought the car, and he experienced the same problem on his GM minivan. I did an internet search and found numerous others (www.GM-v6lemons.com, and other places) who have experienced this problem. It seems clear that the manifold gasket in these vehicles develops leaks when exposed to the dexcool coolant. In my case, the vehicle is 5+ years old, and has 59,000 miles...so there is no warranty in effect. GM should be forced to recall these vehicles and repair this problem.
I own a 1998 Pontiac transport, bought new, and has 80000 miles on it. Was just told that the intake is leaking, ans will need manifold gasket replacement. Was told that there have been numerous reports of this happening. Alled local Pontiac dealer (matthews Pontiac, vestal, ny [phone]) and they confirmed this, and that there is a new and improved gasket, but they wouldn't help with the cost of replacement. Also reported that my headlamp lenses have been lost (lost 2 in one year) and had to replace entire headlamp unit at my own cost. Dealer said this is common also, and they believe it was a problem with the adhesive!! They will not help with that one either.
Tl contact owns a 1998 Pontiac transport. The contact stated that the vehicle's intake manifold is leaking internally and externally in between the intake and the block. He has not contacted the manufacturer due to prior issues with the transmission. As a result, the vehicle consumes a large amount of coolant which contaminates the oil. The engine size was unknown. The current mileage is 65,150 and failure mileage was 65,000. Updated 06/08/07
My wife was driving home from work. The temp gauge went up and the engine had no power. She pulled overhand parked. After the car cooled down I tried starting it and the temp stayed down so I drove the car to the dealership. I felt all that was wrong was the thermostat stuck. Then I get a call that the head gaskets had failed and that the damage was going to cost me $2400 at least that because of the gasket failure all kinds of damage was done.
Intake maniflold gasket leaking anti freeze, dex cool. It cost 1010.27 to repair the engine but now my oil presurre light is flickering when engine idles so there May be some bearing damage. ( cam, rod or main bearings ) the oil presurre sending unit was replaced to see if it had failed still does it. Anti freeze mixing with oil can damage bearings and cause engine to lock up bracking cams and or crankshifts. This can strand us on busy highways.
Where do I start? Same complaints as all other Pontiac minivan owners. Since original purchase in 1998, headlight assembly faulty, ABS warning light malfunction, air bag warning light malfunction, and malfunctioning (still) passenger automatic sliding door. Recently had head gasket replaced due to antifreeze leak, as well as front left wheel hub. This is the worst (and most costly) vehicle I have owned with respect to maintenance.
Vehicle kept over heating. Took it to a mechanic and they changed out thermostat, water pump,temperature sending unit, catalytic converter. Was still over heating. The mechanic checked the engine and found blown head gasket and cracked heads. This problem started out on interstate 15 northbound right outside of barstow, ca. Had to pull over to the shoulder and wait for it to cool down several times so we could get to an exit.
Engine complaints in other Trans Sport years
Frequently asked questions
How common are engine problems on the 1998 Pontiac Trans Sport?
NHTSA has 52 complaints about the engine & cooling of the 1998 Pontiac Trans Sport, 23% of the model year's 227 complaints. The component named most often is cooling system (15 mentions).
Is there a recall for 1998 Pontiac Trans Sport engine problems?
No. NHTSA lists no engine & cooling recall for the 1998 Pontiac Trans Sport, though it has 5 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 1998 Pontiac Trans Sport engine problems start?
Half of the complaints with a recorded mileage happened before about 71,000 miles, and 7% before 25,000 miles.
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.