My 2001 LS430 160k has been a great car until recently I have been hearing an annoying ticking noise coming from the valve covers for about 30 sec after a cold start. It then quiets down but is still audible as a tick some of the time when the engine is accelerating under load. Idle is as smooth as always and no codes. Exhaust checked out for leaks as well. Have always used synthetic oil at 5000 mi intervals and the car still gets great power, gas mileage, and doesnt burn any oil. I am not looking forward to any head work on this car. I thought 3UZ was good for at least 300k with regular maintenance and driven gently.

 

Are you using the proper weight oil?

 

Mobil1 5-30 extended performance every 5000 miles.

 

How many miles on your '01? Be certain the ticking is from the valve cover area.
I would use a product like Marvel Mystery Oil added to the crankcase to clean sticky bucket-style lifters in the LS. BG also makes oil cleaner additives that are used by "L" dealers as well. Using synthetic oil doesn't guarantee that you have no gum deposits on the engine internals.

 

The lifters on these engines aren't hydraulic so they won't make noise like a Chevy V8. The lifter spins in its bore in the head as the lobe pushes it down. This is accomplished with the cam lobe being machined with a very slight bevel. The lifter transfers the vertical motion through the shim underneath it to the valve stem. All 3 of these parts are hardened to reduce wear. It's been debated elsewhere but Toyota doesn't give an adjustment interval because the wear is marginal to none for this type of setup. The valve seat or valve can wear but this would cause a tighter clearance which would cause the valve to leak and the engine to lose power due to lower compression on the affected cylinders.

After all of that I have a very educated guess as to what your issue is: You have a leaking exhaust manifold gasket or a cracked manifold. Textbook symptoms of ticking noise when cold and under load.

 

That is a really good thought about the manifold and I love reading your posts were you a lexus tech? Also what year porsche 911 you own?

 

Thanks. Never been a tech for Lexus or anyone. Just self taught with lots of books, manuals, and experience. One of the few things I haven't done on a vehicle is a transmission rebuild. Within 3 months of owning my LS I had the engine torn down to the short block in my driveway (head gaskets). No Porsches for me. My user name comes from my Camaro, a 1991 Z28 1LE (an extremely rare factory built race car).

 

yah I avoid transmission work it utterly terrifies me and I just did some Google Foo on your car and it is pretty cool man do you have one of the blue ones?

 

I'm not a fan of engine treatments or oil additives in general but I did run about a quart of Marvel Mystery Oil in my 430 for an oil change and I noticed the oil was definitely darker then normal at the standard OCI. The main reason I mention this is noticed the heads seemed more quiet after the treatment. Or I should say valves. Not that mine were loud but the ticking when listening at the valve covers was not as loud. If any carbon is building up in these tiny passages a safe engine cleaning definitely helps.

 

its very very unusual for any uz engine to tick, regardless of oil weight.

 

I bought my SC400 with 99,000 and it was 9 yrs old. The previous owner never replaced the timing belt. I took it in for service and witness the valve covers being removed. Heavy Varnish on the rear of each cover. The previous owner followed Schedule B for Oil changes (7500 mi).
The Tech found 3 valve spring buckets with excess wear and replaced them. One of them is coated inside with sludge. I follow Schedule A now.
In motorcycle engine valve clearance gets tighter as valves wear against the valve seats, especially on the exhaust side..

 

Have you been able to find the source of this sound? My GS makes a similar sound to the one you describe

 

• Remove the engine cover.
• Take a length of rubber hose.
• Place one end at your ear. Point the other end close to, and around the engine to locate the area of the noise.

You can also use a screw driver (preferably one with a long shank) the same way. Only with this method, physically place the end of the screw driver against the engine.

Both methods, the general location of the noise will be obvious. This should narrow down the guessing to just a few possibilities.