2000 Estima, 6 cylinder, makes a short whining noise on start up, also when placed into gear both forward and reverse - mainly when cold - makes a slight knocking sound that fades when you pick up speed,...
The whining noise at start up is either the power steering pump (possibly low fluid, or faulty pump bearing), or possibly a belt on the engine. As for the knocking sound, that is hard to diagnose without actually hearing it, but based on the fact that you are hearing a whining sound at start up, which is indicative of a loose belt, I would start at the belt tensioner and make sure that it is applying the correct amount of pressure on the belts. If the belt tensioner is faulty, it can make a knocking sound. If that is not the issue, then it could simply be the lifters. With engine run time/miles on the engine, internal engine components, such as lifters, valves, bearings and any moving part, deteriorate from friction wear and heat.They have a tendency to make a knocking/rattling sound when they are building up pressure. When they build sufficient pressure, or the engine reaches operating temperature, this sound/noise will dissipate and become nonexistent. This can be remedied by changing the oil, and possibly the weight of the oil (5w30, 10w40, 20w50) depending on your driving habits , or conditions (Highway v/s City/Stop&Go, or short trips under 30 miles)
I hope that you have found this information to be useful, and if I can be of any further assistance, please let me know. Thank you for using fixya!
Oct 01, 2013 |
1995 Toyota Previa