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Cracked Upper Intake Manifold


really awful
Typical Repair Cost:
Average Mileage:
147,959 miles
Total Complaints:
3 complaints

Most Common Solutions:

  1. replace it and live with it (2 reports)
  2. not sure (1 reports)
1997 Pontiac Bonneville engine problems

engine problem

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1997 Pontiac Bonneville Owner Comments

problem #3

Mar 112008

Bonneville SE 3800 Series 2

  • Automatic transmission
  • 140,000 miles


It was a great idea of GM to place a plastic engine part right on top of one of the hotest parts of the engine the EGR pipe. Yeah that didn't turn to ash or anything, cracking the rest of the manifold and dumping all the coolant in to the engine. As it turns out coolant is not a very good fuel for combustion engines. If you have the choice pay less money and get the smaller 3500 engine it's cheaper and engineered well.

- , Milwaukee, WI, USA

problem #2

Jul 212007

(reported on)

Bonneville 3800 V6

  • Automatic transmission
  • 106,876 miles

If you own this vehicle you WILL need to replace the Air intake manifold every 30,000km - 50,000km. Antifreeze leeks in. You can tell by the white smoke/vapor pouring out of the tailpipe.

- , Estevan, Sask, Canada

problem #1

Jan 072007

(reported on)

Bonneville SE 3.8L V6

  • Automatic transmission
  • 197,000 miles

One day, I noticed my engine coolant reservoir was very low. (Looking back, this should have been a big hint to get it checked out.) I refilled the reservoir and went on my merry way. This happened a couple more times, and at that time I was ready to get it looked at. However, for some reason, it stopped. No more disappearing coolant. So I figured I'd stop worrying about it... big mistake. If I would have gotten it checked out at that point, I would have found out that my upper intake manifold needed to be replaced. I could have paid for some engine work and been done with it. Not me.

I had to take it on a trip to a town about 70 miles from home. At about 11:45pm, the engine overheated, started making terrible noises, and died. Luckily, I was able to sell the car to a mechanic who planned on replacing the engine and giving it to his son.

To all owners of GM cars with 3800 series II engines built in the late '90s: keep an eye out for this problem. It is common for the upper intake manifold to break in these engines. If you catch it soon enough, you can save yourself a lot of headaches...

- , Wausau, WI, USA

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