I just got my car back from the dealership they said they repaired the coolent leak they replaced the valve cover gaskets and tube seals, replaced o-rings and water pump. That was on Monday and on Tuesday I noticed the smoke coming from the tailpipe again. Today while driving home the service engine soon light came on I made it home and turned off car I noticed some smoke coming from under the hood, needless to say I have a call in to the dealership, but what could the smoke under the hood mean.

If the smoke coming out the exhaust is white, it could be coolant being burned. Has the car ever overheated? If it has, the aluminum head may have warped, causing the head gasket to blow and coolant to get into the cylinders and be burned. It's not uncommon for valve damage, in these situations.

The under hood smoke may be oil/coolant that is burning off the engine from the repair work.

Don't drive the car, until you know what has happened. It's safest to have it towed. Get a code reader to determine what code is stored in the ECM, when the Check Engine Light came on.