Low Bass and vibration at RPM

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lovemylc

lovemylc

Joined
Jan 11, 2006
Threads
24
Messages
166
Location
Mt Pleasant SC
Hello All - looking for some guidance here.

I have a 97 Lexus LX450 (Black Betty) with 220,000 miles. In the last few months, she has developed a very bassy rumble that is repeatable in-between 700-800 rpms. Does not matter if AC is on or off, in gear or neutral or park. Particularly on start up, this is a bass that you can feel in your chest, not just hear.

My two thoughts are are 1) hole in the exhaust system or 2) something withing the engine is out of sync and is hitting the same rpm as something else, thus causing extra the bass and vibration. I have inspected the exhaust and cannot find a leak....

Thoughts? :frown:
 
Previous work done on the truck? Any codes? PM up to date?
 
All PM is up to date. I am meticulous about going straight by the service manual. The only service work done close to the time ( but I cannot seem to recall the two coming at the same time) was to install OME stock lift kit I got from Slee, along with some spacers.
 
How frequent is the sound?

I have a 97 LX and have experienced this twice and only briefly. One time it felt like it would stall, but did not. I have 202K miles and typically a normal idle.

I have always been curious about this sound.
 
I have the same thing on my 96. It is fine when idling at normal rpm, but when the a/c kicks in and it idles up I get it. I haven't found out what it is yet my self. I have done all all tune up stuff and it is still there. Been thinking of changing the motor mounts to see if that helps. I'll be watching to see how this tread turns out.
 
Try opening the radiator cap after start up. I had bubbles in there and it ran rough. Don't know if this was the true fix. Are you running toy red coolant?
 
Or have you guys checked timing lately? The motor mounts were a thought for me also. Mine hits from 600-2000 and not always. It was after the vavlve cover job I did seems like. Maybe the rough engine shake from valve cover going had a part? I'm very interested to hear suggestions
 
New motor mounts made a huge difference

Sam I Am said:
I have done all all tune up stuff and it is still there. Been thinking of changing the motor mounts to see if that helps
Click to expand...

I was in a similar boat to you guys. My 97 LX with 154K was having a bit of a low frequency vibration right around 800-850 RPM (where it seems to sit when I kick on the A/C). Sometimes it was more pronounced than at other times, but it was more or less always there to some degree. No vibration at all below or above this range when revving the engine. Another symptom I noticed is that the engine seemed to start abruptly - that is, when I turned the key for the ignition, it was like crank crank VROOM. Noting major, but it didn't feel like a super controlled start.

Like you guys, I tried a lot of the usual tune-up things, which didn't really fix the issue. I too suspected motor mounts even though one mechanic told me they looked fine (and did look fine to me also from visual inspection). There are three mounts: two on each side of the engine and a rear one on the tranny cross member. The one on the driver's side of the engine (which would be most apt to wear out) is actually pretty hard to inspect.

I decided to do the mounts anyways and although I usually like genuine Toyota parts, I decided to give these Ebay mounts a shot based on other good reviews of the dealer: http://www.ebay.com/itm/96-97-Lexus...Parts_Accessories&hash=item3f10052982&vxp=mtr

$85 for all three. Not bad.

At any rate, to conclude this, I just got the mounts done today and it has made a HUGE difference in how smooth the car feels and runs. Everything feels tighter, the shifter seems tighter, and no vibration. So, I'm a happy camper right now! ;p

Good luck guys. I hope my experience might help.
 
Sounds like motor mounts. Key observation is the startup. These engines are torquey. My engine rocks the lc at startup. Factory mounts is what I would recommend. And do all at once.
 
FJC80 said:
How much was it to install the mounts, or diy?
Click to expand...

$300. That said, I'm probably in one of the most expensive areas in the country to get any type of work done. It looks like an easy DIY job but the $/time trade off on this one was enough for me to take it in.
 
I'm just starting to experience the vibration in my LX after I dropped the cross member to put in a new transfer case motor. I saw the mount was starting to crack due to the 2 inch drop from lowering the cross member.
 
Well, I too have the exact issue as you gents. I just finished replacing all 3 mounts with Toyota parts and unfortunately, same dang vibration.
I also tried running without any belts also, removing thought of issues with the AC, alternator, or PS.
Anyone have more ideas? I haven't tried the timing yet? What does it need to be set to for a 1995 fz80??
 
I have absolutely zero experience with Motor mounts replacement.

Now that that is out of the way....Is it something where u can work on one mount at a time, fix/reattach it and then go to the next?

Or is it like: detach everything from the engine bay we are removing this pigs heart!! And I would need pullers and stuff...

Simple? Not so simple? Any special tools needed?

Sent from DynaTAC bag phone
 
084runnerltd said:
I have absolutely zero experience with Motor mounts replacement.

Now that that is out of the way....Is it something where u can work on one mount at a time, fix/reattach it and then go to the next?

Or is it like: detach everything from the engine bay we are removing this pigs heart!! And I would need pullers and stuff...

Simple? Not so simple? Any special tools needed?

Sent from DynaTAC bag phone
Click to expand...

Well...since you're in N.D., you need heat and and garage to start.

Next...to replace the engine mounts you'd replace both sides at once as you have to lift the engine up to do the job. A jack under the oil pan or an engine hoist will do the trick.

Trans mount, there's only one, pretty much the same deal, jack up the trans, remover the x-member and pull the four bolts that hold it to the trans and that's about it.

No "special" tools. It can be done with common hand tools save for the floor jack/bottle jack or engine hoist. Simple work but kinda physically exhausting and time-consuming.

Is there a reason you're asking about replacing them one at a time?
 
SBFJ60FIG said:
Well...since you're in N.D., you need heat and and garage to start. Next...to replace the engine mounts you'd replace both sides at once as you have to lift the engine up to do the job. A jack under the oil pan or an engine hoist will do the trick. Trans mount, there's only one, pretty much the same deal, jack up the trans, remover the x-member and pull the four bolts that hold it to the trans and that's about it. No "special" tools. It can be done with common hand tools save for the floor jack/bottle jack or engine hoist. Simple work but kinda physically exhausting and time-consuming. Is there a reason you're asking about replacing them one at a time?
Click to expand...

Thanks

I didn't mean do 1 mount this week....another next week, etc.....

I meant, but it was poorly articulated, if you can remove one mount (leaving others attached) and that they would support the engine, throw in the new mount and then work my way around.

As opposed to, disconnecting all mounts at once, disconnect a bunch of engine components, lift the engine up, install new mounts and lower engine....?

As you can tell, I know nothing about motor mounts or the process to replace them.

So a 3 ton floor jack and hand tools and I am set?

Heat....? What's that? Recently installed my lift in the garage and it was -15......went through 4 propane tanks on my tiny ice shanty heater, but survived. Yesterday snorkel install, but it was a little warmer, I think it was -3. ;)

Sent from DynaTAC bag phone
 
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