1995 ls 400 knock/thump when starting her up
#1
Rookie
Thread Starter
Join Date: Nov 2007
Location: new jersey
Posts: 64
Likes: 0
Received 0 Likes
on
0 Posts
1995 ls 400 knock/thump when starting her up
Wondering what your LS sounds like when you start it up.Mine makes a thump or knock just after I turn the key. It happens when the engine is engaged just after the initial turn.Otherwise, she' s whisper quiet. I recently checked both engine and trans mounts and both were ok. Any ideas or is this normal?
#5
Just an observation...Although the mounts maybe functioning properly you'd be surprised how much less rubber is left on them when compared to a brand new mount especially after 10 years and all the miles accumulated in that time...Mine were "fine" but what a difference when i replaced all 3!
#6
Driver School Candidate
Join Date: Aug 2010
Location: NC
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
Hi, I have a 93 LS400 that I just bought and it appears to be doing the exact same thing. The knock/thump is random on mine. I've previously owned a 90 LS400 and it did not do it all. My immediate thoughts were motor mounts, however the randomness of this confused me. Does anyone know how this played out? (I realize that this thread is 2+ yrs old) Oofer, did you ever get this fixed?
#7
BahHumBug
iTrader: (10)
Hi, I have a 93 LS400 that I just bought and it appears to be doing the exact same thing. The knock/thump is random on mine. I've previously owned a 90 LS400 and it did not do it all. My immediate thoughts were motor mounts, however the randomness of this confused me. Does anyone know how this played out? (I realize that this thread is 2+ yrs old) Oofer, did you ever get this fixed?
Trending Topics
#8
Hi, I have a 93 LS400 that I just bought and it appears to be doing the exact same thing. The knock/thump is random on mine. I've previously owned a 90 LS400 and it did not do it all. My immediate thoughts were motor mounts, however the randomness of this confused me. Does anyone know how this played out? (I realize that this thread is 2+ yrs old) Oofer, did you ever get this fixed?
Good luck!
#10
Driver School Candidate
Join Date: Aug 2010
Location: NC
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
mine also does this random thump at startup, but after reading threads from both CL and LOC on this issue it is definately a result of weakend engine mounts - when I get the budget up will be replacing mine for sure. Amazing difference after just replacing the one Tranny mount.
Good luck!
Good luck!
#11
Driver School Candidate
Join Date: Aug 2010
Location: NC
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
#12
Driver School Candidate
Join Date: Aug 2010
Location: NC
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
Update...
Thanks for the reply. I will definitely keep checking my mounts. However, one of the tests for a bad motor mount is to put the car in gear, press firmly down on the brake and then give the engine some gas. This typically "torques" the engine and if a bad mount is present, it should create a similar knock under that scenario...right? When I tried this today, I got nothing. ??? This is not to say that it is not the mounts, but I seem to be having trouble getting confirmation. Anyhow, thanks again for the reply.
#13
Driver School Candidate
Join Date: Mar 2009
Location: Va
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
My 93 does the same thing. It's not a good sound.What I do now before I start, is turn the key on, buckle my seatbelt, then turn the key to crank. That 10 sec. pause with the igni. on before cranking seems to stop the clunk, bang, booom, which blows the motor mount theory. I replaced the trans mount (very easy) did it in front of the house without jacking the car up. Made zero difference. I would check the engine mounts first, they're probably the cause of most harshness/vibration.
#14
Lexus Champion
How about the oil filter? It might be plugged up and starving the engine of oil when cold.
Thread
Thread Starter
Forum
Replies
Last Post