My 4 runner just hit 108,000 and has been trouble free for the most part. Had to replace the left rear axle seal a few months ago, but other than that it's been great. But this week it starting ticking. The ticking gets faster as engine RPM increases, and it seems to be getting louder lately. Is this a lifter issue? A valve adjustment? Any help would be greatly appreciated. Oil level is good, and it's brand new oil as of last week. Should I stop driving it until its fixed...am I doing serious damage by continuing to drive it?

Thanks,
Michael

 

Can also be exhaust manifold gasket or cracked exhaust manifold. Get your head in there and try to determine where its coming from. (Dont wear loose clothing). Or take it to a dealer and have them look at it.
You can still drive it but should find out what it is.

 

Use a mechanic's stethescope to see where the noise is coming from.
They are pretty cheap and widely available.

My bet would be either lifters or more likely an exhaust leak.

 

Thanks for the feedback... would it help to differentiate between the possible causes if I told you that it doesn't tick when the engine is cold??

 

With an exhaust leak, I would think that would be when the tick would be the loudest because the metal hasn't expanded yet due to the heat. Do you guys think sludge build up would cause this? I know some of the earlier 3.4s had problems with sludge build up. It could be a number of things though. Like possibly a bearing on one of your accessories making a little noise. Just do what the others said and try to locate the noise.

 

Finally took the 4Runner to the dealership to have it looked at. Turns out it wasn't the lifters or an exhuast leak...it was an arcing spark plug! The dealership up in San Francisco who put in Bosch Platinum Plugs for me didn't tighten on of the spark plugs enough and it worked itself loose, almost to the point of completely falling out. So, the ticking was coming from the arc being created. I had the dealership here replace all the plugs and the ticking is gone. This dealership down here in SoCal also said that the 3.4L engine does NOT like platinum plugs...kind of strange, but ok.