I have a 3.1 Malibu that was overheating, it has water in the oil and now it’s idling at about 2k What is causing the high idling? Is it a crack head or a bad head gasket or something else?
HELP
Probably the Intake Manifold Gasket. This is a common problem with GM’s V6 and V8 engines. You need to get this fixed FAST. If you’re the original owner then you “might” be able to get GM to fix it for free.
I agree with Mike. This is classic lower intake gasket failure symptoms. Unlike most other engines, the 3.1 will scream rather than stall with a vacuum leak. Overheating and coolant in the oil also occur with the failure of these fantastic plastic intake gaskets. You may also consider having a thorough coolant flush done and go with either traditional green coolant or the universal long-life stuff they have now. Almost anything is better than dexcool.