1998 Pontiac Bonneville: engine overheating

Filed Apr 8, 2013 · Engine · 62,000 miles · VT · fire

Tl* the contact owns a 1998 pontiac bonneville. The contact stated that while driving 20 MPH, the vehicle overheated. The contact then attempted to park the vehicle however, the vehicle then stalled without warning. The vehicle was taken to a dealer for diagnosis and the contact was informed that the intake manifold was melted and the head gasket was blown. The vehicle was not repaired. The failure and current mileage was 62,000.

Filed Feb 9, 2007 · Engine · 41,500 miles · MI

I am the owner of a 1998 pontiac bonneville with a 3800 engine. I am the original owner and the car has less then 42,000 miles on it. The upper intake (plenum) and seals have failed resulting in coolant leaking into the engine. I phoned an acquaintance who worked as a technician at the gm power train engineering facility in flint, michigan where the 3800 engine was engineered. He said it was common knowledge by the engineering skilled trades employees that the upper intake design was flawed. There were many intake failures observed during dynamometer testing. Some even exploded. I was told that the engineers and management was well aware of the defective design, but for some reason, changes were not made. I can direct investigators to employees who witnessed intake design failures in the testing facilities.

Filed Dec 22, 2005 · Engine · FL

1998 pontiac bonneville overheated. *ts the consumer stated the engine started to sputter and then would pick up abruptly and then the engine light illuminated. The consumer was told water was coming out of the plug holes. The consumer had the vehicle towed to another establishment where he was then told the entire engine had to be rebuilt or replaced. The mechanic stated the manifold had a leak at the throttle body. The consumer stated the problem has resurfaced again 4 years later.

Filed Dec 13, 2005 · Engine · 60,000 miles · FL

There are 313 complaints on this website as of today concerning the 1998 pontiac bonneville. Out of those 313 reports, at least 132 are 100 percent related to the plastic manifold failure which causes the engine to overheat to catastrophic results. I have had to replace the engine on my vehicle twice within 4 years. Gmc is refusing to acknowledge this issue and it is a shame that the almighty dollar is more important than integrity,honor and people's lives. What happened to pride in what you manufacture?shame on gmc!!!

Filed Apr 5, 2005 · Engine · 72,108 miles · WI

For the second time in about 2 years my 98 bonneville had the plenum crack while simply driving at normal speeds. This allows water to enter top of motor which requires vehicle to be shut off immediately or motor will overheat until it is ruined. The car had about 50,000 miles at first occurrence and has 72,108 miles on it when it occurred again last friday. Car is undrivable until parts can be bought and installed, making this a very dangerous situation if you are on highway when that occurs. It has cost more than $ 800.00 each time to get vehicle fixed and I now have no trust in this part of motor what so ever as there is no real reason why it occurs other than plenum being plastic so it can't stand up to normal pressures or temperature changes. Vehicle manufacturer has admitted they made a fix for problem but it is at owner's expense which does not seem fair as this is an obvious design flaw which allows dangerous situations for owner to happen.

Filed Nov 15, 2004 · Engine · 68,000 miles · IN

Upper intake manifold developed a coolant leak into cylinders. On startup, the engine hydrolocked. When engine hydrolocked, the starter was damaged and had to be replaced. The intake manifold and spark plugs had to be replaced. The dealership said this is a common problem and all manifolds will eventually fail.

Filed Oct 6, 2004 · Engine · WI

1998-bonneville 70,000 miles. Started stalling intermittently on one occasion, got car to mechanic and found out that the upper plenum had a hole burned right through it. Had to replace the upper manifold because of coolant leaking into the engine. $910.00 later it is fixed. Did some research and found that gm is aware of this problem and know of numerous complaints about this. Wondering when they are going to call for a recall??????

Filed Sep 20, 2004 · Engine · 96,098 miles · WA

While driving 55 MPH vehicle overheated. White smoke came from the tail pipe. Vehicle was taken to a dealer, who informed consumer that the problem was a crack around the egr located on the intake manifold.

Filed Aug 20, 2004 · Engine · CT

I have a 1998 pontiac bonneville which was brought into the dealer for repair due to not having any heat in the car. I expected a faulty thermostat or some other minor problem. It turned out that engine coolant leaked out from the plenum, water pump and gaskets requiring replacement of the water pump, water pump belt, and manifold (with the various gaskets) manifold was actually rotting from the inside due to coolant leak into it. This repair cost over $1,000. Upon talking to the dealer and my own internet research this is a common problem with the gm 3800 engine which is in bonnevilles, grand prix and buick lesabre. I reference the federal safety agency consumer complaints listed under bonneville and grand prix complaints of "engine cooling systems" and "engine." I also direct you to edmunds.com "town hall" section(bonneville and grand prix) that is a chat room that shows numerous complaints about the exact same problem. I guess I was lucky in that at least my engine didn't completely seize as is also common when the antifreeze coolant leaks into the combustion chamber. Gm will not reimburse me a dime on the cost. This car has just 36k miles on it but it is 4 1/2yrs old and thus out of warranty. The car has been properly maintained, including a dealer oil change just 2 months prior to this problem. My research has shown that the engine coolant leakage from the plastic gaskets and plenum into the manifold and combustion chamber is not an isolated incident and needs the federal safety agency to investigate this issue further. Gm customer service is of no service and they have basically told me to buy japanese from now on. *sc

Filed Aug 15, 2004 · Engine · 58,183 miles · GA

No events lead up to the failure, it was immediate. Car stopped dead in its tracks, started one more time before it died in 1/8th of a mile. I was informed that the intake manifold was the problem coolant leaked into the engine. *jb replaced intake manifold,gasket,oil filter, oil, coolant & spark plugs.cleaned out coolant from intake and cylinders. Change oil and filter.

Filed Apr 20, 2004 · Engine · 28,000 miles · OR

While driving engine was leaking coolant onto the intake manifold. This could result in engine failure. *ak consumer was informed by her friend that her vehicle was on a list of potential engine failures from coolant leaking by general motors (gm). Consumer went to a gm dealer as soon as she learned the news, and showed extensive damage on the intake manifold which was replaced.

Filed Jan 5, 2004 · Engine · 72,967 miles · NJ

Intake manifold leaked coolant into engine. Seems the plastic intake manifold and gasket warped causing excessive coolant consumption into the engine.