rough starting and blows smoke. engine light on

Just had the timing belt, water pump, drive belts etc done for the regular maintenance and then the engine light came on with code po116. Toyota dealer told me they would change thermostat and ect sensor. They told me that if that didnt work I might need a new computer module at the cost of $1500.... Brutal. This van has just cost me $1700 for the belt pump and sensor... Fingers crossed that the light doesn't come on again. Im not spending another $1500 on a 16 year old van.

Update from Nov 12, 2016: There is no sludge issue with this van. I don't know why car complaints automatically assumed it was engine gelling. The problem was the ect sensor and thermostat. Hopefully not the computer module. Will know soon if engine light comes on again.

Every morning and mid afternoon when I start the van, a thick cloud of white smoke spews out of the tailpipe. It continues for about 5-10 mins then eventually stops. This repeats everyday. I tried using stop-smoke additives, one called ProTech I saw on YouTube . It was expensive... $29 per can . It didn't fix it if course. I took it to a mechanic but he couldn't recreate it. He kept saying its normal and just to live with it. It's very embarrassing when smokes inside a parking structure and everyone is staring at you while covering their noses.

Mechanic says if it's the seals or gasket it'll cost me $2500. Heck NO! The van is only worth maybe $1500.

I'll likely get rid of this and cut my loses.

We purchased our 2000 Sienna in July of 2004 and were told that there had been only one other previous owner before us. This vehicle was also a "Certified Toyota Used Vehicle" that supposedly had gone through 160 rigorous check points! NOT! I have recently found out that at the time that we purchased this vehicle the dealership knew of a defect that was in the engine that caused this particular engine to turn the oil into a "Gel"! This, in turn, causes the engine to fail! A Technical Service Bulletin came out on this in 2002. This does not always happen quickly, especially if you have your oil changed regularly, like we have. It can take years for it to blow smoke ,as mine did, but the first sign is the check engine light coming on, which mine did well over 2 years ago. My local Toyota dealership would tell me each time I called or went by that it was an O2 sensor gone bad or that it was just my gas cap needed to be tightened! They never said you need to bring it in because that engine has a defect and needs to be checked! They knew exactly what the real problem was but did not want to say because it was not "smoking" at the time. They can blame a check engine light on over 200 possible problems. They never even did any paperwork when I would come in because they did not want a paper trail that could be traced! We have owned four Toyotas in our lifetime and we are only 37 years old. We will never buy a Toyota again! This problem has not been resolved because Toyota is denying paying for the claim and we do not have $4,000 to $6,000 to fix our car at this time (Which really needs a new engine because if they only replace the valve system and clean the gel out it will just come back again). I am not giving up though. I will take this problem as high as it can go! Toyota's customer service or lack there of is the reason I will never buy a Toyota again. I understand that engines can have flaws but for Toyota to not stand behind their product like they are doing is an insult to this "used to be loyal" customer! Let me also add that if I did not have a family member that could loan me a vehicle while I fight this fight then I would have probably had to trade the Sienna in and take a huge loss because of the costly repairs it needs! Not to mention we only have 3 payments left! This is NOT what I expected from a Toyota. Anyone that wants to find out more about this problem can go to oilgelsettlement.com and get educated. Or put "2000 Sienna Smokes on Start Up" in Google, like I did. If I can find this info so quickly why did the dealerships never know?!?!