07 4runner 2uz engine sound diagnosis when cold or under load

[BulletHead]

anyone experience rattling/knocking sound with the 2uz when cold or under load?

it first appeared a few months ago and it was intermittent. i took it to the dealer and they replaced the belt tensioner and then charged me $100 for the serpentine belt since it had some wear (or so they claimed). this was at 59k miles, so i was still under warranty. i do have the 125k extended warranty. obviously their fix didnt solve the issue, the sound returned the next day.

now it appears every morning and again in evening if i let it cool down for about 1 min and sounds like knocking. i did do a search and looks like the uzj100 experiences the same issue and it could be exhaust manifold cracks? i hear a similar sound while i accelerate and downshift going 20-30 mph.

 

[vwluv10338]

I was going to say it but you nailed it at the end, cracked manifold. Those engines don't have many problems but if you have a ticking while cold I would look at the manifold.

Eric
Master Lexus Tech

 

[BulletHead]

is there a certain area where they typically crack or side of engine?

i wonder if the warranty will cover it.