First, you need to stop the check engine light from flashing. That means that you are doing severe damage to the engine. You can check the codes and see what is malfunctioning. If that is too much trouble, just cut the wire going to the check engine light. Once you get all of the problems causing the light to flash, it may run at normal temperature, or you may have a cracked block or head, or a bad head gasket, if it is not something that the other people have listed.

It probably needs an intake manifold plenum assembly, they crack around the EGR passage then start to ingest coolant!



NOTE: The 3.8L (Series II) is famous for this problem!

Why do you bother to ask when it is obvious you don't do any repairs. And I'd bet you don't have any money so just keep driving it, it will die a slow and painful death soon. But just think you can start over again killing another car.

Only o/heats at high speed? Coolant flow may be restricted. Try flushing and filling, and change thermostat. Make sure not a lot of debris in radiator fins, and airflow not blocked.

Time to take it to a professional.. be prepared for an expensive bill (possibly thousands for engine replacement) also catalytic converter replacement..

Keep in mind you may be better off getting a newer or different car.

Your lucky it lasted this long, I know you don't wanna hear it but you got as much use out of it as your gonna get. Kick that thing to the curb before you get stranded in it.

Ok so my car is in bad shape. Its a 2002 buick lasbrae 3.8 engine its misfiring the check engine light is blinking when im accelerating im onlys getting like 12 miles a gallon now my car is overheating but it has coolant then when its hot i open the radiator coolant like bubbles n flows back into the overflow but it only overheats when im accelerating on the highway when i get off onto regular roads it cools down and dosnet overheat?? Any suggestions on what any of these problems could be???