'98 Engine Noise Diagnosis

[CA Cruisin]

Sorry CA, no verdict yet. It's my budget truck and I'm slow. Mine takes about a minute or two before the noise shows up, then doesn't go away.

I haven't done a compression test or arranged any shop diagnosis yet.

OK, thanks for letting me know. Please keep us posted! Could help others out. Mine only happens when it's cold overnight or outside and then the sounds go away after a few minutes. The colder it is outside, the louder and worse the sound. Local mechanic said valve lifters but he's not a LC specialist-type. May be the manifold?

 

[camino70]

I pulled the plugs today for compression testing, I haven't done research on what's "good", but I'm telling myself these are good and close:
#1 = 190
#2 = 210
#3 = 190
#4 = 190
#5 = 190
#6 = 195
#7 = 210
#8 = 190

Put the plugs back in and pulled the drivers valve cover. Nothing jumping out at me as a problem, nothing appears to be missing/broken/touching anything it's not supposed to.

The exhaust cam gear appears to be two pieces, is that correct?

cam gears

• camino70
• Mar 19, 2016

Just a pic of the cams, again, no research, so not sure this looks good:

cams

• camino70
• Mar 19, 2016

I had my daughter spin it over with the cover off and nothing seems wrong.

I'm not sure why I'm doing this....

 

[CA Cruisin]

OK, thanks for letting me know. Please keep us posted! Could help others out. Mine only happens when it's cold overnight or outside and then the sounds go away after a few minutes. The colder it is outside, the louder and worse the sound. Local mechanic said valve lifters but he's not a LC specialist-type. May be the manifold?

OK, my noise completely went away... tapering off from one day to the next... a mechanic spilled antifreeze everywhere working on the car and it messed up some belts and made things sound really off. Guess it burned off because now the LC is back to normal.. Started it up at 30 degrees this morning and nothing odd-sounding occurred.

Not super helpful, just wanted to share my experience.

 

[ton504]

Sounds like a collasped lifter. One of our techs had one a gx470. I personally thought it was an exhaust leak but it turned out to be one of the hydraulic lifters.

 

[2001LC]

I pulled the plugs today for compression testing, I haven't done research on what's "good", but I'm telling myself these are good and close:
#1 = 190
#2 = 210
#3 = 190
#4 = 190
#5 = 190
#6 = 195
#7 = 210
#8 = 190

Put the plugs back in and pulled the drivers valve cover. Nothing jumping out at me as a problem, nothing appears to be missing/broken/touching anything it's not supposed to.

The exhaust cam gear appears to be two pieces, is that correct?

cam gears

• camino70
• Mar 19, 2016

Just a pic of the cams, again, no research, so not sure this looks good:

cams

• camino70
• Mar 19, 2016

I had my daughter spin it over with the cover off and nothing seems wrong.

I'm not sure why I'm doing this....

Nice camino70, great pictures.

FWIW: FSM compression 192 PSI or more, minimum 142 psi with engine hot. No more than 14 psi difference between cylinder's.

I just did mine with 25 year old gauge. I was very slow (2 hour for first reading from engine off), letting engine cool a bit too much. Forgot to open throttle all the way (doesn't allow full intake of compressible air). And battery; a weak Wal-Mart special (may have not made minimum crank speed of 250 RPM). I ran 191 psi +- 4 psi with no real leak dn. By that I'm mean; I saw some, about 3 psi drop in first 30 seconds, but held over next three minutes with no more loss. This made me think it's my gauge, as cylinders held pressure, otherwise I should have seen pressure continue to drop. I repeat in future and follow the FSM to the T, with new gauge just to see. But I'm happy with results.

Lets us know the valve gap, now that covers are off. You'll be the first I've ever seen reported here.

Valve clearance (Cold):


Intake

0.15 - 0.25 mm (0.006 - 0.010 in.)

Exhaust

0.25 - 0.35 mm (0.010 - 0.014 in.)
____________________________________

@ton504, our 2UZ-fe in the 100 series have solid lifters.

 

[camino70]

I was just reading over the 2004 FSM this morning and noticed the Full Throttle statement, I did NOT do that. The 190's may have been 192, my gauge's display isn't the greatest and frankly I was expecting #1 or #3 to be zero or substantially lower than the rest.

I reinstalled the valve cover for now, but it's not too bad to remove, I will probably get around to testing the clearance on #1 and #3 in the near future. Let's say it is out of spec where I could re-shim it, I can't help but think a weak valve spring is the root cause?

 

[2001LC]

I was just reading over the 2004 FSM this morning and noticed the Full Throttle statement, I did NOT do that. The 190's may have been 192, my gauge's display isn't the greatest and frankly I was expecting #1 or #3 to be zero or substantially lower than the rest.

I reinstalled the valve cover for now, but it's not too bad to remove, I will probably get around to testing the clearance on #1 and #3 in the near future. Let's say it is out of spec where I could re-shim it, I can't help but think a weak valve spring is the root cause?

The Schedule Maintenance booklet, states check valve gap. The test/check is sound. If they are louder than normal, then next step is checking valve gap. You missed a great opportunity to check that off your list of causes of your sound concern. I would think a weak spring would not make any loud sound or tapping.

 

[2001LC]

But you know I've not been convinced your sound isn't normal. But with recording it's very hard to make any call. I hear it, the tapping, but these engine are a little noisy. Is microphone just making it sound worst than it is. They all sound noisy until operating temp is reached, then smooth out a bit provide you have good oil & oil pressure.

 

[camino70]

Small recap, compression testing NOT done by the book. It was cold and throttle NOT open:
#1 = 190
#2 = 210
#3 = 190
#4 = 190
#5 = 190
#6 = 195
#7 = 210
#8 = 190

Cold valve clearance:
3, 5 and 7 within spec, 1 #1 intake out of spec (I need to find my numbers).
2, 4, 6 and 8 NOT measured

Intake
0.15 - 0.25 mm (0.006 - 0.010 in.)

Exhaust
0.25 - 0.35 mm (0.010 - 0.014 in.)

MPG's hover around 14mpg with mixed driving

I don't feel a power difference from my 2004 LC.

Idle is fine, just noisier, no vibrations.

I haven't seen a CAT or O2 CEL, but have had two coil pack failures 10K ago, replaced all 8.

 

[2001LC]

Small recap, compression testing NOT done by the book. It was cold and throttle NOT open:
#1 = 190
#2 = 210
#3 = 190
#4 = 190
#5 = 190
#6 = 195
#7 = 210
#8 = 190

Cold valve clearance:
3, 5 and 7 within spec, 1 #1 intake out of spec (I need to find my numbers).
2, 4, 6 and 8 NOT measured

Intake
0.15 - 0.25 mm (0.006 - 0.010 in.)

Exhaust
0.25 - 0.35 mm (0.010 - 0.014 in.)

MPG's hover around 14mpg with mixed driving

I don't feel a power difference from my 2004 LC.

Idle is fine, just noisier, no vibrations.

I haven't seen a CAT or O2 CEL, but have had two coil pack failures 10K ago, replaced all 8.

That could well be your "tap". Let us know when you find that number. Your FSM will give proper shim size to correct.

This may be the first recording (I've heard) of a 2UF-fe valve gap out of spec in mud.

BTW I chased down my tick on the 01LX, it was the DS #1 exhaust manifold. This was report as replace by dealer years ago. Christo at Slee told me he's never seen a replacement crack. So either it was a fluke or the Dealer burned the PO.

 

[sean2202]

Thanks for the update. Out of curiosity I have searched valve tappet and shim replacement on 2uz-fe on net and have come up with nothing. No videos on YouTube of valve clearance checks or shim replacements on 2uz. Wonder if shims available? Do you have exact readings? Did you measure on opposite end of cam lobe?Mine readings were all on the tighter side.

 

[2001LC]

Wide gap = tap. If gap wide enough, sound will be same even after warm up, as metal can't expand enough.

I've gone back and listened to your recordings of cold & hot engine. Since you've eliminated the fuel injector(s) I'd say it is 70% sure this is a sound due valve lifter gap. If gap measured wide, it 90%

You may try a few more test to help confirm to get to 98% certainty:

1. Use stethoscope along different points like intake port to head for #1,3,5, 7.
2. Listening through the oil cap. Not sure how will this will work with vacuum pressure drop. Try covering with hand & rag and with rubber hose held over and in the oil filler neck.

I hope you do re-shim and document with video & pictures. I've not done the job but have looked at it. Accurate dead on measurement is key to a fast job.
This job will take someone with OCD, it's a , that take precession & patients. Are you up to it. You may become a star.

 

[sean2202]

(9801-0505)

This might be helpful. Shim is PNC number 13753 in picture.(intake and exhaust) Called Toyota and was told there are "many combinations of PNC 13753" From my understanding when out ofspec, shim has to be removed, then measured with a micrometer then correct size shim has to be used to get valve clearance back in spec. The person I spoke with said there may be a number on the shim. Toyota said the shims are available but the person I talked with hasn't seen it done .

 

[Julian Stead]

What where the measurements?

 

[Julian Stead]

On OHC engines, I have only ever reshimmed due to tight valve clearances, the valve seats get worn and close the valve gap, pretty common when they introduced unleaded fuel, not so much now. Unless you can see wear on the cam or lifter it is hard to see why the gap would increase unless there is a valve issue. Your measurements could contradict what I say there though, and then you will need to reshim. Reshimming is a fairly straight forward job, just get the maths right and you will only need to get the shims required, one maybe two..

 

[2001LC]

I've always found it interesting that Toyota recommends checking valve gap "by sound". Interesting because I'd think gap narrowing (tightening) would be most common, from reason you've stated Julian also valve stem stretch. I can't see how a tight gap would cause a "sound". This is why I'm always looking for data on gap. As gap out of spec will reduce performance, and narrow gap would be undetectable during recommended PM inspection.

 

[fj55-100]

many shims , we do these all the time . not uncommon to fine some out of spec . takes alott of clearence to be able to hear a click

 

[2001LC]

many shims , we do these all the time . not uncommon to fine some out of spec . takes alott of clearence to be able to hear a click View attachment 1392249

Very interesting you do these all the time. You're talking about the 2UZ-fe of the 100 series correct?

You're the first I've heard this from in 13 years of looking on mud & Google.

Please give a little color here, like:
What prompts you to check gap in the first place?
Any performance issues associated with gap(s) out of spec?
Are you finding them loose or tight most often?
How many mm out of spec on a average?
Any pattern to maintenance history like poor PM of oil change history or type of oil used?
Associated with any particular cylinder more often then others or is it random?
Any other issues associated with gap out of spec. i.e bucket of head or lifter out of spec, lob of cam worn, valve steam, seat issues. etc...?


Thanks in advance

 

[fj55-100]

ok . not wanting to stir the pot . just thought a picture was needed . worked for lexus for 20 years toyota for 7 . now own my own , . valve adjusment used to be a required inspection at lexus at the 90 k service . about 2000 we stopped that due to the cost . on the 4.7 the shim is under the bucket which is under the cam . so t-belt and 4 cams need to come out if shim replacement is required . intake shims would go tight and exhaust shims would be loose , just what we would find on a day to day basis . no performance issues . rear most cylinders .,propper maint is the best preventaive

 

[2001LC]

You're not "string the pot", I really appreciate your input.

I've long held the belief that valve gap needs to be checked physically (feeler gauge) by visual inspection. Toyotas' recommended inspection is an audible test, which didn't seem like a good practice. I suppose cost of ownership being so completive among auto manufactures weighted on Toyota/Lexus in making this change. That thought concern cost of ownership and from your statement I gather; as valve gap(s) go out of adjustment, some, most likely exhaust will get noisy then all need physical checking.

My experience with old V8's (1960 & 70's), adjusting valve gap gave me improved performance and needed done on regular basis.

Thanks again for your input.