2007 Camry 4cyl not a hybrid

Okay sounds like something is mixing in the combustion chamber coming out the exhaust. 99% of the time this is related to a blown head gasket or crack in either the head or block. If you purchased the new rebuilt engine from a reputable re-manufacturing company like Jasper as a long block, meaning came with the head attached from the re-manufacturing company Then if a leak is occurring from the mixing of coolant into the combustion chamber then it would be covered under the warranty providing you didn't overheat the engine due to a faulty coolant fan that failed.This could have been over looked by the mechanic by not diagnosing why the head gasket failed in the first place and effecting that repair after the new engine was installed.The fan should come on after reaching normal running temperature that is about 195 degrees. If the fan does not turn on ( faulty ) ,you drove the car and you do not have a temp gauge to tell you the car is overheating then you most likely blew the head gasket again. Ff course this is providing you have exhaust fumes in the cooling system. Most reputable shops have a chemical tester that will detect exhaust in the cooling system while running the car. This tester is squeeze rubber clear plastic tube filled with a clear blue chemical with a rubber tapered nose . it is simply inserted in the radiator or reservoir bottle where the fill cap is removed.With the engine running the rubber top section is squeezed sucking in the air from the coolant system and if there is exhaust in the coolant system the blue chemical will turn green. If so you have a fault in the head gasket, block or head. If it was a short block purchased with a recondition head either it was not tourqued in the right sequence and correct torque specification psi or the re-manufactured head was not checked properly ( magnaflux and surfaced checked ). I would have the block test done as described to rule out blown head gasket. If it is blown by all means have the fan checked and repaired as well.

also if it is oil mixing and not coolant then this may be a bad valve seal. If it is a blown head gasket you may have moisture in the oil. look for a milky oil on the tip stick or under the fill cap. Even moisture under the fill cap without a milky mix is a sign of a blown head gasket.

The white smoke would be constant. As sometimes when a vehicle is started moisture my be present due to condensation from hot to cold and with only smoke slightly as is wars up and dissipates.

This is a new rebuilt motor. It started easy and ran smooth with no smoke on initial start up. It was not until the car got warm/hot (about 3-5 minutes) that it started to smoke from out of the exhaust. It appear to have some smoke in the engine compartment too. He shut it off before any damaged could occur. It was not driven on the road. Could the old fuel have any connection? I'm thinking NOT likely. It should have a new thermostat with the new rebuilt motor. I had a new water pump added as well. My mechanic is going to try pulling any codes later today. The radiator was only a few months old when the old engine overheated, so I did not have it replaced with the new rebuilt motor.

drain the fuel tank and fill with new fuel as well as replace the fuel filter and see what happens. How about the fan ? is it working at all?

Thanks for the replies. I appreciate all the possible reasons offered! It was a long block with the head already mounted. The engine rebuilder compression tested it before shipping. (FYI Jasper is not as good as it used to be. I have heard many recent story of rebuilt engine failure) The electric fans worked after the overheating of the original overheated motor. With an open circuit when we moved it (Key in on position, to move trans in in neutral) it was running.) I will have the mechanic, check the fans circuts again to be sure. We never drove the car to overheat the rebuilt motor. The second start up resulted in the same results. It started fine. ran well with no smoke, then once it warmed up smoke began pouring out the exhaust. I asked him to drain the tank and add fresh gas. He doesn't think it's the issue. I'll go there and check the oil and the coolant. Hopefully he had the coolant chemical tester you mentioned. His last thought was the head gasket was put on upside down. Has was going to call the engine builder next after checking for codes and any other possible issues. I'm beyond frustrated with the whole ordeal, but will report back with any updates. Thanks again.

It was the Catalytic Converter! My mechanic talked to a few Toyota tech buddies who all agreed it was the likely candidate for the issue. Sure enough, the third time he started the motor there was less smoke after it warmed up. There was a lot of moisture coming out the exhaust (new muffler and resonator). The temp on the Cat is a bit high, but there were no codes thrown. It's possible the Cat might need to be replaced, but they suggested it might clear itself out with a few long drives. Once again, thank for all the replies.

Look at the cat at night when the engine is warm and running.I've seen them glow red hot when clogged. Even piratically clogged and running causes back pressure. Your opinion is noted on the jasper engines and I assume that's why they have a 3 year or 100,000 mile warranty parts and labor should one fail. I have three all over 20,000 so far but I could just be lucky. Time will tell as with any rebuild.

After a couple hundred miles all is good. It passed inspection (emissions) in NJ without any issues. Thanks for the note to check the catalytic converter at night for any glowing. The mechanic had a code reader which indicated cat temps. The temps dropped with each drive down to a normal operating range. That was relief.

glad everything is ok