1998 Lexus Ls400

[gifted-tulip]

Guys, Occassionally after parking my car for 5 - 7 days,I hear valve taping sounds coming from the engine. Is this a major concern? The car has 191000 miles on it at present. The taping is loudest when the engine first starts then gradually disappears over 30 to 45 seconds at idle. The engine is working normally most of the time. I would appreciate your help. Is there anything I can do? I use 5w-30 80% synthetic oil in it and 5w-30 is the recommended oil by manufacturer.

[steve2006]

This is a known problem with the engine but they never seem to get any worse with time.

The valve clearance is done with shims and although you can replace these with different thicknesses to acheive the adjustment it is both a labor intensive job with expensive parts.

The noise probably sounds worse as the engine oil will have drained from the top of the engine having been stood for 5-7 days so until full lubrication is regained it will sound noisy.

If it disappears in the time you say I wouldn't be unduly worried.

I was once advised that on higher mileage engines a 10W-40 oil could be used which with a slightly thicker viscosity may help.

[gifted-tulip]

Steve thanks for your thoughts. Glad to hear its not serious. Does any engine damage occur during the time the valves are taping?

I thought of using 1 qrt of 10w-40 in my next oil change but this may be to conservative. I usually change oil every 4000 miles. I looked at the exact time the car was parked before starting it. The time was actually 8 full days. I will try to avoid leaving it parked that long in the future...plan to keep it under 5 days.

I have a question assuming proper maintenace, what is a reasonable life expectancy of this 4L engine.?

Does the A/C compressor need any service at any time?

[turboomni]

I own a 1997 ls400. It was quiet when I bought it and about 6 months later I heard a valve noise that would be noticeable at start up and then go away when warmed up. After awhile it took longer to go away. Then it was consistent in varying degrees which *BLEEP*ed me off. I researched valve adjustment and realised it is all done with shims and such which I would guess is very time consuming especially if you have 32 valves to check......I then made another discovery from this forum I believe. It could be the EGR pipe which is on the back of the block. I got my stethoscope [heater hose] and while running listened and the sound and when in the back of the block I heard it loud and clear the valve noise. Got a mirror and realised it [egr tube ] was cracked. I am not up to such a task of replacing this anymore and my starter went out. While the starter was replaced I had him replace the egr tube and the problem was/is gone. It also cured a vacume leak a rather big one but I really didnt notice a rough running engine,,,,but when I got it back it was as smoooth as silk and quiet. I hear this is a common [egr pipe] problem especially on high milage cars with worn engine mounts. I had the mounts replaced too. It may not be your problem but I would suggest checking the egr pipe before you dig in any further. It is also a real pain in the @ss to replace all 4 bolts. The manual states to remove the tranny to replace this tube....it can be done in other ways, much cheaper,,you need an inovative mechanic.