Do any of you dudes replace the timing chain as a preventative measure? My 89' TOY has 170,000 miles with the original timing chain, and I am wondering if i should replace the timing chain or just wait untill it breaks??
More than likely the guides will break before the chain does. Most of the time it is the guides that break and allow the chain to slap the inside of the timing cover. You dont want this to happen because it will eat away the aluminum and then cause coolant to get into the oil. As we all know coolant and water together is not good. I cant think of anytime I have replaced a timing chain due to preventative maintenance. However when the guides go out you are best off replacing the chain and all. SInce the guides breaking allows the chain to stretch. The most obvious way to know if the guides have broken is the noise you will hear from the chain when the chain starts slapping the timing cover. You can pull the valve cover off and look down the front of the timing cover and try to look at the guides. If i rememebr right there are two bolts for each guide. Also if I rememebr right it is normally the top bolt hole on the drivers side that breaks first. take a flash light and look in there to see if you can notice the guide broken. IF it looks like on of the bolt holes is broken then you need to go ahead and take care of it before it gets worse. As the guides break they end up in the oil pan and if it all goes then you have to pull the pan. IF the chain does end up breaking then you know you may have to pull the head because the 22R series of engines is an interference engine.