Three problems related to engine and engine cooling have been reported for the 1998 Toyota Sienna. The most recently reported issues are listed below.
I came home and turned my ignition switch off but my 1998 Toyota van kept running. Turning the key on and off did not turn it off. I tried shutting it down with the ignition switch again and again and again. I tried turining it off again while moving the gear selector lever but to no avail. I begin to smell burning rubber. I lifted the hood and realized the engine was being turned over by the starter which was not disengaging and starting to smoke. Then tons of smoke began boiling off the starter. I disconnected the positive battery connection and the engaged starter stopped cranking the engine. Heavy smoke continued boiling from the starter for about a minute longer. I was very glad I was not inside the garage because I think the starter could have started a fire or the smoke would have smothered me.
Engine oil sludge: my Sienna was finally fixed by Toyota canada after I made numerous complaints about the dealership (jim pattison Toyota) that refused to repair the vehicle. The whole engine was overhauled by a different dealership. I was really happy the way they handled the case. I just received a memo from Toyota yesterday that Sienna between 1998-2000 have problems with the transmission. They have extended the warranty on transmission for these particular vehicles to 8 yrs or 100,000 miles .
Engine had to be replaced due to oil sludge, oil changes were made made promptly.