I have a 2002 Toyota Highlander 6 cyl, 148,000 miles. I get a cloud of white smoke from the tailpipe upon starting a cold engine. Smokes for about 1-2 minutes, then smoke stops. Any thoughts?
Are you needing to add coolant? or oil?. If not, likely your injectors are worn or dirty allowing fuel to puddle on the pistons and light off when started. If the smoke is more blue-white and your oil consumption has gone up a bit lately, it may be leaking valve seals. If it is white and a little sweet smelling, coolant is finding its way into the combustion chambers - head gasket has failed.
Hold a white cloth or paper towel over the tailpipe while someone else cold starts it. The towel should be a little wet from the exhaust, if it is quite wet and smells sweet - coolant. If it is mostly oily, well, oil. If it smells like gasoline or solvent-y, injectors. If it is either of the first 2, have a compression (or leakdown, preferably leakdown) test done. That should confirm or deny the problem. If it is injectors, run a couple of tankfuls of injector cleaner through the truck and restest.
If it is the 5vz it’s more than likely valve seals, pretty common issue on high mileage engines. If you are loosing coolant it could be a head gasket starting to fail. Check your fluids and see what is low. Has the check engine light came on or does the engine run rough when first started?
My guess, valve stem seals. My Chevy started with a puff of blue smoke, solved it by replacing valve sttem seals.
My guess if valve stem seals and possibly exacerbated by valve train sludge leading to oil pooling, all depending upon the oil change regimen and oil type.