Engine Clatter

[LexusLooker]

OK brain trust, please do your magic!

98 LS, purchased 9 months ago with 15K miles. Since then I've put 30K on it, so it's had a huge lifestyle change. Many times, but not always, when I start it cold, there is a distinct valve clatter for several seconds. It tends to go away with an oil change. Also, when fully warmed up but idling, the engine just sounds "sloppy". It may be an exhaust sound (EGR tube?), or it may be valves, kinda softly clattering. Not as loud as at startup, but not a smooth sound. All sounds are heard with the door open or outside the car; I never hear anything inside. It is possible I just never listened closely enough, but it just sounds raggedy, like an old GM engine...I'm not GM bashing, just imitating the older, more mechanical, sound. I don't think it's the normal injector noise. Power is fine.

Some history. The car had the oil changed by the dealer on a mileage schedule for that first 15K. So that means it went a couple of years or more between changes...ouch. I have changed it every 5K since using 5W-30 and Toyota filters. A coworker's husband worked for Park Place Lexus and recommends 3K changes, so I've gone to that. The oil at 5K is definitely dark, as well as somewhat "sticky". So I'm thinking it's kinda sludgy. I have done 3 changes in a row at 1K each as a kind of flush. The oil comes out new looking. Should I do a few more of these? I know I might get flamed, but I went to Mobil 1 this last time for the detergent effect. I know not to use additives, but what about one of the sludge flushes that you let circulate for 10 minutes just before an oil change? Or should I pull the pan and look at it?

Or I may be off track entirely by looking at the oil. The plugs and timing belt have never been changed because the mileage limit has not been reached. However, they both are past their time limit. Could the raggedy sound be from the timing being off because the belt is stretching and/or the plugs corroded? If it matters, the serpentine belt hasn't been changed either, and it's just showing signs of cracking.

Your advice is appreciated in advance!

James

[ArmyofOne]

OK brain trust, please do your magic!

98 LS, purchased 9 months ago with 15K miles. Since then I've put 30K on it, so it's had a huge lifestyle change. Many times, but not always, when I start it cold, there is a distinct valve clatter for several seconds. It tends to go away with an oil change. Also, when fully warmed up but idling, the engine just sounds "sloppy". It may be an exhaust sound (EGR tube?), or it may be valves, kinda softly clattering. Not as loud as at startup, but not a smooth sound. All sounds are heard with the door open or outside the car; I never hear anything inside. It is possible I just never listened closely enough, but it just sounds raggedy, like an old GM engine...I'm not GM bashing, just imitating the older, more mechanical, sound. I don't think it's the normal injector noise. Power is fine.

Some history. The car had the oil changed by the dealer on a mileage schedule for that first 15K. So that means it went a couple of years or more between changes...ouch. I have changed it every 5K since using 5W-30 and Toyota filters. A coworker's husband worked for Park Place Lexus and recommends 3K changes, so I've gone to that. The oil at 5K is definitely dark, as well as somewhat "sticky". So I'm thinking it's kinda sludgy. I have done 3 changes in a row at 1K each as a kind of flush. The oil comes out new looking. Should I do a few more of these? I know I might get flamed, but I went to Mobil 1 this last time for the detergent effect. I know not to use additives, but what about one of the sludge flushes that you let circulate for 10 minutes just before an oil change? Or should I pull the pan and look at it?

Or I may be off track entirely by looking at the oil. The plugs and timing belt have never been changed because the mileage limit has not been reached. However, they both are past their time limit. Could the raggedy sound be from the timing being off because the belt is stretching and/or the plugs corroded? If it matters, the serpentine belt hasn't been changed either, and it's just showing signs of cracking.

Your advice is appreciated in advance!

James

Here is your problem, most likely. your timing belt has slightly stretched due to age, and is hitting (slapping) its plastic timing belt cover. it happens on my car too. change the TB it willl likely go away. i would do that anyway as your engine is an interference motor. if the timing belt breaks, your motor will be toast.

[monarch]

I'd suggest getting two opinions from two different shops to see if their diagnoisis's match. Only a minor issue is likely causing the noise (e.g an exhaust manifold gasket leak, fault with an ignition system part, etc.). I can't think of hardly anything the original owner could have done to the car during it's first 15,000 miles that could have caused internal engine damage. 15,000 miles is not enough miles for sludge to form, even if the oil was not changed for 2 years. Plus the Lexus V8's are not prone to developing sludge.

[sha4000]

army i doubt the TB has stretched with that low mileage and the 98ls doesnt have a plastic cover their aluminum. i know what this guy is talking about b/c i get that same noise and its most likely an exhaust leak or in my case the valves need adjusting. its noticeable upon start up but not so much after the car warms up, this doesnt affect power in any way

[ArmyofOne]

army i doubt the TB has stretched with that low mileage and the 98ls doesnt have a plastic cover their aluminum. i know what this guy is talking about b/c i get that same noise and its most likely an exhaust leak or in my case the valves need adjusting. its noticeable upon start up but not so much after the car warms up, this doesnt affect power in any way

oh, yeah i just noticed the mileage. your right that isnt likely.

[LexusLooker]

Whew, when I saw Monarch's name, I thought "Oh NO!! He's going to spank me for a) inquiring about a sludge flush and/or B) using Mobil 1!" Thank you Monarch for the advice - I'm glad to hear you think it's fairly minor. I'll get it looked at. And I promise to return to dino juice in the future :)

Army and Sha, thanks for your comments too. I'm nervous about the TB being so old, and had the same feelings as Army about it being flaky, but EVERYBODY I've talked to locally tells me to just chill and wait until 90K.

Happy New Year guys.

[sha4000]

i hope eveything works out

[90LS400Lexus]

15K miles on a 98'? Wow, that is low. I also doubt that it is your belt.

However, at that mileage, the engine should be in perfect working order, without any bizarre noises to speak of @ all.

I am wondering though... you said it runs "sloppy". Has the car been setting for a long time? If so, perhaps you have some old gasoline? Perhaps a fuel filter is in order?

[nc211]

15K miles on a 98'? Wow, that is low. I also doubt that it is your belt.

However, at that mileage, the engine should be in perfect working order, without any bizarre noises to speak of @ all.

I am wondering though... you said it runs "sloppy". Has the car been setting for a long time? If so, perhaps you have some old gasoline? Perhaps a fuel filter is in order?

Ahh, there ya' go! I think you're probably in need of some seafoam injector cleaner. Good answer 90! I would call your dealership and ask them what they recommend in terms of injector cleaner. I think mine says some sort of product called bf44?? that's not it, but close...i can't remember. I would also think she's probably due for a country road cobweb blow-out....if you get me drift..

[sapper_daddy]

As far as fuel injector cleaning goes the best luck i ever had was on a mahince degined to clean them. It costs about eighty dollars or so. It's made by snap on and there is a special fluid that it uses. I had it done on my ford f150 with 200,000+ and it worked like a charm.....what they do id purge your gas into a tank in the machine. Then, they add their snap on fuild. They completly disonnect your fuel system and plug into your intake then run the pump one way to clean the injectors then in reverse to clean cylinder heads, valves and plugs, works great and takes about two hours. You can probably find someone locally at a well setup shop.

[monarch]

Whew, when I saw Monarch's name, I thought "Oh NO!! He's going to spank me for a) inquiring about a sludge flush and/or B) using Mobil 1!"

I hope you will tell us when you find out what is causing the start up noise and raggedty warm engine sound.

I feel the source of the noise will turn out to be due to a fairly minor mechanical fault such as a loose spark plug, breached gasket, hole in a hose or tubing, disconnected hose or tubing, etc. A more serious, but unlikely source of the noise could be from permanent (but not immediately fatal) valve train damage caused by oil starvation. For example, when the former owner had the oil changed the technician could have installed the oil filter improperly, causing the oil to leak out. Or the technician could have accidentally forgotten to refill the engine with oil before restarting and driving the car.

On the other hand, if the source of the noise is determined to be due to deposits inside the engine or fuel injectors, then the "mechanic in a can" "pour in the cleaner and fill the neighborhood with smoke" "get a Motorvac" oriented folks here will have scored some good points.

[LexusLooker]

Some good ideas, guys. I would think that the 30K higway miles I've put on it (so it's at 45K now) has blown all the crud out (including some country road runs, NC211...I live in the country so I get to do that sometimes...that baby can HAUL), but I have noticed on a couple of occasions the cloud of smoke when I punch it HARD. I may need to do like my old Mercedes mechanic, who was German, would tell me to do: "You need to drrrrive the car! Drrrrive it hard to clean out the eenyecktors (injectors) and show it who is bossss".

The morning startup sound is a starvation-type sound...valve clatter that goes away as oil pressure / flow increases in a few seconds. My fear was similar to what monarch said about valve train damage - that oil sludge had gooped up the narrower passages and was starving the engine more or less all the time...causing slow damage. I don't think the sounds were there when I bought the car.

Bad gas, huh? Hmmm...hadn't thought of that. I fill up a couple of times a week, but the previous owner obviously didn't use much gas in 7 years/15K, and NEVER drove on the highway...so gunked up eenyecktors could be possible from that. Interesting about the snap-on power flush thing. And NC, I think I have heard of BG-44 or something. BG Products is a familiar name.

So here's my plan. This weekend, I'll listen all around carefully to see if I can pinpoint the location of the warmed-up sloppy sound - indicating a bad gasket/loose plug/exhaust leak/leaky hose. I'll also pull a plug to see what shape they're in. They may be toast from burning old crud out (i.e. cloud of smoke, above), or be corroded and inefficient, causing carbon buildup. They should have been replaced at 4 years. That should give me enough time to stall and figure out whether to do a DIY eenyecktor flush or get a pro to do it, or do like monarch says and take it to two differernt shops for their advice.

Thanks for all your input guys...very thoughtful.

James

[monarch]

If the prior owner consistently drove 2,000 miles per year (= 4-5 tanks of fresh gasoline per year) then that would be plenty to keep the fuel system and fuel injectors in good shape. On the other hand, if the car was in storage for a 1-2 year period or more anytime during that 7 year period then I'd be concerned about the possible effects the deteriorated gas would have. I know from personal experience a Toyota engine will run roughly if fed 1 1/2 year old gasoline.

Your comment about seeing a cloud of smoke makes me more concerned about possible internal mechanical damage to the engine. A '98 Lexus should not produce any visible smoke from the exhaust no matter how wildly you drive it. I'd pull all 8 spark plugs and look for differences in the amount of wear / deposits on the plugs. Worn / dirty plugs or partially melted electrodes could indication piston ring or valve damage on one or more cylinders.