peppertree

My 1997 LS400 has 160,000 miles and is now exhausting some smoke and has a light knocking at start up. My trusted mechanic tells me the lifters are going and some oil is making its way to burned from possibly the rings not sealing well any more. He changed the oil to a semisynthetic and put in some kind of conditioner in the new oil, designed to quiet the lifters. It does seem a lot quieter now but still smokes a little. He says to just drive it until it gets really bad, or it is some $3000 to to do an upper cyclinder job, and a lot more to hone the bore and do new rings. I thought these motors were last a lot longer. Any thoughts?
Jeanette

Kansas

My 90 LS was running the same as when it was new at 183,000 miles when I finally sold it after 13 1/2 years. I think the current owner has over 240,000 miles on it and occasionally tells me that it is doing well and that he loves the car.

Valve noise at start up is fairly normal as these cars age but the clicking noise usually quiets down after a few minutes. Is the car using a lot of oil? Is the compression way down? Is the car low on power?

Minor smoking does not mean that the engine is worn out.

If you have not owned the car since new, do you have documentation on whether or not it had regular oil changes before you owned it?

LSPiNoY

iTrader: (1)

i have a 1990 LS400 with ~260,000+ miles. still runs strong.

Thermactor

iTrader: (1)

Well - go to www.auto-rx.net and do the treatment. It could do the trick. You have some deposits built up in your engine probably that need to get flushed out. The RX will help gently clean out the deposits and make the car quieter.

Bill Dowd

I use Mobil one full synthetic oil and lucas oil snythetic additive I have 195,000 miles and it runs fine. I use the 10-40 weight mobil one and change it every 10-12,000 miles. I always check the oil level at 3,000 miles or if you run a half quart low the oil light will come for a few seconds and go off. As far as possible having deposits in the enginer use lucas fuel injection cleaner and take the lexus some saturday morning on a nice long trip say 50-100 miles to give the engine a good cleaning. If you should happen to always drive in town and bumper to bumper traffic take a run on a saturday to just clean out the carbon in the engine. HAPPY MOTORING.

RA40

iTrader: (6)

Welcome to CL.

If you are really curious and don't mind paying ~$100...have a compression check done. This way you have some idea how worn the rings are. I'm not sure of the psi level...guessing 160-180psi normally. (Can somebody verify?)

How is the tranny...regular fluid drains?
At what point did you acquire the car?

91LS400LEX

When I sold my 1990 LS400, it had 252K miles. Engine was all-original... it had never leaked or burned a drop of oil between changes. No smoking either. I think that 160K is the lowest mileage I have ever heard a LS400 smoking. In fact, I personally have never seen a Lexus LS burning oil, but iI am sure there are some out there?

SW07ES

Only Lexus dealers, Toyota dealers and Toyota specialty service shops are qualified to determine the cause of the smoke and engine noise because only they have Toyota specific knowledge and expertise. Ordinary "mechanics" don't. In fact it appears your "trusted" mechanic isn't even aware that the Lexus V8 doesn't even have hydraulic valve lifters that can "go bad".

160,000 miles is just the break in period for a properly driven and cared for Lexus engine. But if you are not the original owner then it's possible the prior owner could have damaged the engine via neglected or delayed preventive maintenance. As RA40 mentioned, a compression test can tell you whether or not the engine has serious mechanical wear or damage. Readings should be
up in the 170-190 PSI range on all 8 cylinders if the engine is still in good mechanical condition. If your engine has good compression then the cause of the smoke is likely something minor and the cause of the engine noise is something minor too like loose valve clearances or an exhaust manifold gasket leak.

PK_Celsior

iTrader: (18)

my 95 ls400 has a lot of smoke from the exhaust. from start up im surprized i past smog in cali . the engine noise usually is your valves clicking its nothin serious. to what my lexus mechanic friend told me. i have 200k miles. my motor still surviving my lexus mechanic said my compression still good :].

Bradster

1990 LS400 with 240K miles..purrs like a kitten..changed to Amsoil 100K miles ago and never looked back

ttyR2

312K miles and no smoke or anything else odd comes out of the exhaust system.

persian451

the LS lasts forever with proper maintenance

Bill Dowd

A possible link for the car smoking could be the valve guide seals when the car sits over night or for a couple hours a small amount of oil will go down the valves and come out the tail pipe. If this is the problem just use good oil and change it every 5k or use mobil one and change it every 10k. If you drive the lexus in town all the time take it on a open highway and run it about 50-70 miles and clean out the carbon and gunk in the engine if it is always highway driven you wont use much oil and I would't worry about it. Just keep a log on how much oil you have to replace every 5,000 miles if not much drive the hell out of it the car was built to run and run hard.

Zoraone

First - The 1UZFE doesn't have lifters. The cam lobes sit on a flat tappet that actuates the valves.

A lifter, in its simplest forms exists in pushrod engines. My LS2 has hydraulic lifters. The lifters ride on the single cam inside the bock an actuate the valves via pushrods an rocker arms.

The small smoke you are seeing is probably from leaking valve stem seals. Nothing major. These seals get old and small amounts of oil leak down into the combustion chamber while the car is sitting. Upon start up this oil is burned and exhausted.

Oil is cheap. Don't worry about it.

CptnTonus

The 1UZFE does have lifters, they just don't "lift" on anything like most people are used to, they push. The technical term is a hydraulic lash adjuster, or cam follower. I would imagine the 1UZ uses solid lifters though, since you have to adjust the valves every-so-often. As far as I know, all piston engines use some type of lifter, it's just not called a lifters perhaps.

My LS400 ticks most of the time, especially on cold starts. I can't tell if it's an exhaust leak, or if the valves need adjustment, but the car doesn't smoke or anything. I'm almost at 237k miles and she's running strong!