Whole Lot of Clanking Going On 1998 LS400?

Messages
5,056
Location
VA
I had my timing belt, water pump, idlers, tensioner, thermostat (first time replaced), cam seals, crank seal and the two cam gears replaced on
my 1998 LS400. All Toyota parts from Lexus dealership. Everything put back together and when mechanic started it up,
I heard this knocking and I thought I was gonna pass out. My 20 year old friend was making a lot of noise. Mechanic said
he was stumped. He had gone through everything twice. The engine is not missing. It was not and had not ever made
this noise in 20 years. It didn't use oil per se but the cam gears were leaking and making a mess in my driveway.

My Lexus contact (not mechanic, just a great friend) said the make sure the bolts go back through the holes on the cam
gears to make sure the cam shaft still had tension on them ???. He said to check compression and look inside the cylinders and
see if something had accidentally fallen in. Since the intake was not removed, that was a long shot but something may have
gotten sucked in through the throttle body.

Bore scope showed nothing in the cylinders. Compression was fine. Timing marks line up perfectly. The first time he tried to
get the 10 mm bolt to go through the hole in the passenger side cam gear it didn't go in but 1/2 inch. Subsequently attempts
while rotating engine 180 degrees then allowed the bolt to go through the passenger side.

My mechanic and Lexus contact (with engine specialist) are talking and scratching their heads. If I have to, I will tow it to Trav's
house. Anyways, I'm open to any idea or suggestion.

When I figure out how to post a video, I'll have it for you so you can hear the knock.
 
Messages
199
Probably have **** on the belt and it's skipping on the water pump or alternator causing a weird engine clank sound noise... heard that before many times. When the belt cleans off it goes away.
 

Nick1994

$50 Site Donor
Messages
13,429
Location
Phoenix, AZ
How long did you let it run?

I had a 97’ Camry and after I changed the timing belt it made a bad noise for a minute and then went away.
 
Messages
17,634
Location
...
Oh my, this sounds familiar.

I know someone who replaced a air conditioner compressor on a Lexus about the same age as yours. When he reinstalled the bolts some of them wouldn’t go in all the way. He later found out that the bolts had to be marked to correspond to the holes they were taken from.

Long story short, he installed two bolts with brute force until they finally went in. Unfortunately they breached the block.

I hope this isn’t the case in your situation but double check the bolt mounts and especially any that were hard to reinstall.
 
Messages
1,822
Location
RI
Post the video when you can and we can better tell you what’s going on. Extremely unlikely that anything is “in the cylinders”.
 
Messages
1,331
Location
canada
Well, I learned how to post of YouTube. Easy Peasy....
sounds like its coming from higher up on the motor, wonder if you have a faulty tensioner or pulley thats bad right from new ?? that is a stomach turning sound to hear on start up after all those repairs..

listened closely this time to the video, wonder if cam timing is slightly off
 
Last edited:
Messages
1,822
Location
RI
First step is what trav suggested. Doesn’t sound good and definitely not normal. If it stays, which I bet it will, have to pull the timing covers back off and check everything.
 

Gebo

Thread starter
Messages
5,056
Location
VA
It’s in a “secret” facility that cost me $175 towing which Erie reimbursed. LOL

The original mechanic was unsure how to reset the “tension” on the camshaft bearing?? He charged me nothing for what he has done and feels humiliated.

It is supposed to be checked this evening. I will definitely update. I’m guessing the teardown will begin today. I’m not expecting to know anything til late Sunday.
 

Gebo

Thread starter
Messages
5,056
Location
VA
WOOHOO!!!!

Problem solved. All is well! Lexus mechanic said I was good for another 300K.

Do you see the problem?
 

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