YACT: Rattling noise

[PoPPeR]

Car is a 1991 Lexus LS400. There seems to be some sort of rattling noise from the front of the car when a certain amount of pressure is applied to the accelerator. It's incredibly annoying... any ideas?

 

[RagingBITCH]

That doesn't help much. Where is the rattling coming from? Inside engine compartment? Suspension? Driver/passenger side? What speeds is it rattling at? Have you checked inside the compartment for any loose pieces that might be clanking around?

 

[myusername]

What octane gas you use? Next time you fill up, switch brands and buy the 93 octane - see if that helps.

 

[Zenmervolt]

How much is "a certain amount of pressure"? What are the conditions like? Hot? Going uphill? Heavily loaded?

There are many possibilities. Could be as simple as harmonics causing vibrations elsewhere, or it could be pinging (which would be solved by higher octane, though the LS400 should have knock sensors that would eliminate pinging, so that's an unlikely problem).

ZV

 

[JonTom]

Just found out yesterday that my rattling under acceleration is my engine mounts...

Does the noise appear under torque?

 

[PoPPeR]

well the noise is definitely not from the interior, something like "engine mounts" sounds accurate but I'm not a mechanic by any means. It's a pretty fast clicking noise that dissapears as soon as I give the car more gas or slow down. It doesn't matter if I'm going 10 mph or 50 mph, it'll make the noise regardless. Happens when engine is cold or hot, downhill or uphill, any conditions pretty much. I think it's just something that is connected to the accelerator somewhere but I dont' even know if that's a possibility.

 

[PoPPeR]

and I think my local shell is 91 octane for premium

 

[PoPPeR]

Originally posted by: RagingBITCH
That doesn't help much. Where is the rattling coming from? Inside engine compartment? Suspension? Driver/passenger side? What speeds is it rattling at? Have you checked inside the compartment for any loose pieces that might be clanking around?

I could check my engine but honestly I wouldn't have the first clue where to look. It's more on the drivers side but it's quite loud, you can hear it from anywhere

 

[CrackRabbit]

May be your CV joints going out, does it happen mostly when you turn?

 

[BCYL]

I think engine mounts would be the most probable cause here, definitely check that out first...

 

[PoPPeR]

Originally posted by: CrackRabbit
May be your CV joints going out, does it happen mostly when you turn?

no, doesn't matter what my car is doing at the time... straight, turning, as long as that special amount of pressure is applied to the accelerator itll rattle

 

[JulesMaximus]

Originally posted by: JonTom
Just found out yesterday that my rattling under acceleration is my engine mounts...

Does the noise appear under torque?

 

[Zenmervolt]

Originally posted by: PoPPeR
I think it's just something that is connected to the accelerator somewhere but I dont' even know if that's a possibility.

It's not a possibility.

Probably harmonics causing something else to rattle when the engine is under a certain load and throttle condition. You'll need to have a mechanic diagnose this one in person I'm afraid.

ZV

 

[PoPPeR]

doh... is it a good idea to get it checked out (safety wise)? It's pretty annoying but if it's most likely not a hazard I might just endure it

 

[Zenmervolt]

Originally posted by: PoPPeR
doh... is it a good idea to get it checked out (safety wise)? It's pretty annoying but if it's most likely not a hazard I might just endure it

If I don't know what it is, how am I supposed to make a judgement call on whether or not it needs to be fixed as a safety issue?

It might, it might not.

Have it checked.

ZV