1998 LS400 185K Vibration Issue
11-29-17, 12:56 PM
#1
Driver School Candidate
Thread Starter
1998 LS400 185K Vibration Issue
Greetings and Salutations, ClubLexus members! I recently purchased my very first Lexus LS 400 and I'm brand new to the forum and I already have a question for you guys. I'm getting vibration that can be felt in the seat and car even when the car is in park. No vibration at idle (~700-800RPM) but if I give it some gas and get the RPMs around 1200 I can start feeling the vibration. The higher the RPMs get (say 2000) the stronger the vibration. When the car is moving, it's smooth until about 40MPH (~1200-1400RPM) and the vibration can be felt. At 65MPH-75MPH there's even a throbbing in the vibration and the ride is just rough overall. I'm the second owner of the car and the previous owner was not very good with keeping maintenance records. That was almost a deal breaker because I was concerned about the major services like timing belt, etc. Luckily there was a sticker in the engine bay placed by Eskeridge Lexus in OKC with mileage and date of when the timing belt service was done (136K/2010). Since the purchase, I've done the following: Engine oil changed with Mobil 1 5W-30, Transmission filter (ATP - Amazon)+ 4Q tranny fluid (Toyota Type 4 ATF - Amazon) replaced, rear diff fluid (Mobil 1 Synthetic gear fluid - Amazon) replaced, spark plugs replaced (Denso Iridium plugs - Amazon) and ignition coils replaced with Spectra Premium from RockAuto, air filter replaced (WIX - Amazon), 2 hood shocks replaced (StrongArm - Amazon), installed 4 Continental PureContact touring tires (Discount Tire), brought coolant within range in reservoir (Toyota pink super long life coolant). Brake and power steering fluids look okay. I asked the Toyota technician who was performing all these maintenance tasks for me about checking engine and transmission mounts and he said they looked good. I'm listing all the stuff I've done to give you guys a picture of what the current condition of the general maintenance items is currently. Any help with figuring out the vibration issue will be greatly appreciated. Thanks!
Last edited by musafir; 11-29-17 at 01:40 PM. Reason: Typos
11-29-17, 01:20 PM
#2
congrats on the new car and good job on getting the maintenance off to a good start.
sounds like you have an unbalanced crank pulley (or loose), fan, or something RPM related if you're just revving the car and the vibes are already felt without the car moving.
have someone rev the car and take a look at the engine to see if there is any abnormal movement on the fan (will be hard to see if movement is small).
I've seen a crank pulley separate before but it's not common.
do you have any check engine lights?
sounds like you have an unbalanced crank pulley (or loose), fan, or something RPM related if you're just revving the car and the vibes are already felt without the car moving.
have someone rev the car and take a look at the engine to see if there is any abnormal movement on the fan (will be hard to see if movement is small).
I've seen a crank pulley separate before but it's not common.
do you have any check engine lights?
11-29-17, 01:29 PM
#3
Driver School Candidate
Thread Starter
No CELs or any other lights are on. The engine does sound a little louder than it should (I think - could just be characteristic of a 20yo V8). I don't have another LS 400 to gauge the sound by, though. I let the engine run with the climate control on and at idle I don't really hear any excessive sounds coming from the engine while standing in front of the car with the hood up. I'll have someone rev it and see if I hear or see anything you're recommending. Thanks for the reply! The car is a joy to drive even at 19 years old.
Last edited by musafir; 11-29-17 at 01:48 PM.
11-29-17, 01:34 PM
#4
Lexus Champion
Greetings and Salutations, ClubLexus members! I recently purchased my very first Lexus LS 400 and I'm brand new to the forum and I already have a question for you guys. I'm getting vibration that can be felt in the seat and car even when the car is in park. No vibration at idle (~700-800RPM) but if I give it some gas and get the RPMs around 1200 I can start feeling the vibration. The higher the RPMs get (say 2000) the stronger the vibration. When the car is moving, it's smooth until about 40MPH (~1200-1400RPM) and the vibration can be felt. At 65MPH-75MPH there's even a throbbing in the vibration and the ride is just rough overall. 'm the second owner of the car and the previous owner was not very good with keeping maintenance records. That was almost a deal breaker because I was concerned about the major services like timing belt, etc. Luckily there was a stick in the engine bay placed by Eskeridge Lexus in OKC with mileage and date of when the timing belt service was done (136K/2010). Since then I've done the following: Engine oil changed with Mobil 1 5W-30, Transmission filter + 4Q tranny fluid replaced, read diff fluid replaced, spark plugs replaced with Denso Iridium plugs and ignition coils replaced with Spectra Premium from RockAuto, air filter replaced, 2 hood shocks replaced (StrongArm), installed 4 Continental PureContact touring tires. Brake and power steering fluids look okay. I asked the Toyota technician who was performing all these maintenance tasks for me about checking engine and transmission mounts and he said they looked good. I'm listing all the stuff I've done to give you guys a picture of what the current condition of the general maintenance items is currently. Any help with figuring out the vibration issue will be greatly appreciated. Thanks!
OEM is more expensive, but they are fluid filled
It does not matter if the mounts look good...if original, the rubber is 20 years old
11-29-17, 01:46 PM
#5
Driver School Candidate
Thread Starter
Thank you for the input. I have the two engine mounts and one transmission mount (all Toyota OEM) inhand right now. Just wanted to be sure that's the cause. Especially if the Toyota tech said they looked good. What should the labor be for all three to be replaced? Around 2 hours?
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11-29-17, 03:11 PM
#6
Lexus Champion
Thank you for the input. I have the two engine mounts and one transmission mount (all Toyota OEM) inhand right now. Just wanted to be sure that's the cause. Especially if the Toyota tech said they looked good. What should the labor be for all three to be replaced? Around 2 hours?
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03-20-18, 01:14 PM
#8
Driver School Candidate
Thread Starter
UPDATE: THANK YOU to all who provided their valuable input. I put up with the vibrations up until last week. Took the 2 new Toyota engine mounts and transmission mount to Lexus service and had them change the all three mounts. With 188K miles on the clock, the car now runs like a brand new car. I couldn't even tell if the engine started or not the first time I started at service when picking it up. I can't believe simply changing the mounts would make the car feel like a brand new car with a rock solid ride now. Now I know why the LS400 has the reputation it has for the ride.
03-20-18, 01:59 PM
#9
Probably the tranny mounts, but engine mounts could be suspect also. You don't really how bad they are until you remove them... then they break in two because they are so hard and brittle. Glad you got that straightened out. Now you can enjoy the ride.
Welcome the car and the club.
Welcome the car and the club.
03-20-18, 02:53 PM
#10
UPDATE: THANK YOU to all who provided their valuable input. I put up with the vibrations up until last week. Took the 2 new Toyota engine mounts and transmission mount to Lexus service and had them change the all three mounts. With 188K miles on the clock, the car now runs like a brand new car. I couldn't even tell if the engine started or not the first time I started at service when picking it up. I can't believe simply changing the mounts would make the car feel like a brand new car with a rock solid ride now. Now I know why the LS400 has the reputation it has for the ride.
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