I own a 1997 Buick LeSabre (60K miles). I like the car, but I have also experienced the intake plenum problem. In talking to GM service managers as well as independent shops, it seems that this is a common problem. I had the car repaired at an independent shop. The owner is a former GM service manager. He told me that some previous customers were able to get reimbursement from GM. I contacted GM. The customer service folks admitted that they receive a lot of calls about this issue. However, they refused to reimburse my repair costs because I had not tried to get the problem fixed at a GM dealer... but I had no idea what the problem was prior to taking it to the shop! GM service reps told me that they deal with this issue on a case by case basis... I think this issue should be addressed by a recall... all owners should be made aware of this potential problem with the 3800 Series II engines...
1998 LeSabre - My plenum cracked and blew coolant into all the cylinders at hwy speed. The coolant flooded the engine so quickly it stalled. I had the car towed to a GM dealer and there was no warranty and no admittance of wrong doing on GM's part. They had this funny look on their faces, like, we know whats going on, but we won't admit to the manufacturing defects. Cost was $800.
I was lucky, a friend of mine put a piston thru the block and broke the crankshaft of his car... cost him $5000 for a new engine. He said his coolant went into one cylinder only and when the piston came up it couldnt compress the water.
I found out from a parts supplier that they sell lots of the plenums and the problem is on 1997 to 2003 3.8 engines. There must be millions of those engines out there... now you know why GM won't back up their cars. He also told me that the after market carquest plenums are redesigned to correct the problem.
I don't know if the dealer put another bad GM plenum on my car.
This car will need to be replaced soon and I'm very reluctant to by another GM because they aren't being honest with their customers.