Hi fellow RX300 owners,

My RX300 is 5 months old and it has 9000 miles. A few days ago I started hearing this "tap..tap..tap" sound from the engine. Thinking that it was a faulty belt, I went to the dealer only to be told that it was a "TAP PAD" problem (huh?).....

The said that the pistons have gaps at the top, and they need to remove the engine to measure the pistons and align them properly (huh?)

They also said that it is a common thing (I never had any of these from my previous cars) and that I can choose to do it during the next service.

Can anyone throw some light on this please.

Please help me cause my Lexus now sounds like a beat up wagon....and I don't think the dealer is being very honest.

Thank you.

James from Singapore

 

I'm not sure what your dealer is telling you there. There IS a gap between the top of the piston and the top of the cylinder; that's where your fuel/air mix goes. But the piston travel is not adjustable since it's attached to a big hunk of metal called the crankshaft. It goes up, it goes down and the difference between top dead center and bottom dead center is the stroke length ("stroke" for short). This cannot change unless either the crank or the pistons or both is/are replaced.

I can understand your skepticism. Still, it's warranty work, therefore I'd give the dealer a shot and ask for a better explanation of the problem and the fix.

 

"If" this V6 uses hydraulic lifters for valve actuation, I would say it's a valvetrain clatter problem. What the dealer is saying is really left field IMHO. Most likely, it's maybe some sticky lifters or the oil is draining out of them at night.

Are you using a Toyota/Lexus oil filter? If not, what kind? If the filter doesn't have a decent antidrain back valve design, it could be allowing oil to drain back into the pan.

 

It could also be your injectors. Most of the people that I heard from in this forum have the same symptom; noisey injectors. Took it to the dealer and they called it out before I told them. It's "normal" and nothing to worry about if this is the case. Here's the post from a little while back...

https://www.clublexus.com/forums/sho...threadid=29599

 

thank you to those who helped out....now I'm told it's either the Tappet Clearance that needs adjustment or the Injector.

Funny thing is that there is no sound when the engine is cold...sound comes only after 10 mins drive.