Four problems related to coolant leaking have been reported for the 1998 Oldsmobile 88. The most recently reported issues are listed below.
Yesterday our car began overheating. We added a bottle of coolant yesterday and another two gallons today along with a bottle of stop leak and had it towed to our mechanic. Our mechanic told us it seems like the engine has seized completely and he is not equipped to fix it.
Faulty head gasket resulting in coolant leak and damage to engine costing $2946. + car rental.
Engine sputtered and shut down causing loss of power steering, power brakes, etc. Fortunate not to have happened at high speed or in heavy traffic. The engine locked up completely and would not restart. Cause was coolant leakage through crack in plenum which had to be replaced at a cost of over $700. This is very likely the cause of the following consumer complaints listed on your site: odi id's - 553119, 883623, 886028, and possibly others that were unexplained. I only searched for olds 88, but the same engine is used in pontiacs, and other gm makes. This problem is common enough to have been listed by the automotive service assoc. Of arizona repair shops - see their website and an article under the title "coolant leakage" which explains the problem very clearly. The plenum is plastic, and is simply subjected to more engine heat than it can safely handle over time, causing the cracks to develop over time, hence the continual and gradual loss of coolant until it finally gives way resulting in too much coolant leaking into the engine to allow for combustion. As stated earlier, this engine shutdown could be very dangerous at higher speeds or in traffic.
While driving the engine gasket leaked coolant which caused the vehicle to overheat. The consumer had to replace the entire engine.