Revisited post -- https://g35driver.com/forums/6741773-post13.html

Original post below:
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I've noticed recently that at partial throttle right at 30mph i'd hear a slight rattle from the engine. I'm not an engine guru but wild guess is it sounds like something is turning faster than another part attached to it.

I can easily replicate it by going just beyond 30, letting off gas then partially pressing the pedal down again.

It's easily heard when driving newly laid asphalt where tire noise is not drowning things out.

I've read that this may happen to the HR and could be normal. To some degree it's supposedly intrinsic to the VHR (thus their use of Ester oil).

Can anyone provide insight? Could it be the chain? Or an exhaust shield and whatnot?

Thanks.

 

anyone?

 

Im having this same exact issue! Let me know what you hear.

 

Sorry Mike, don't know how I missed this thread.

No matter though, as I don;t have any answer for you. I have not heard what you're describing, either in an HR or a VHR, so I can't speak to it. I know the VHRs are supposed to be more prone to some valve noises with their VVEL technology and I think they had some actuators that made noise too, but that all wouldn't explain anything to do with your HR.

 

I am experiencing the same thing. Well actually, it only happens while the car is at idle. It sounds like it is coming from the HFC's. The passenger side in particular. It doesn't happen right away. I have to drive fleeted. After that, I can hear the rattling sound as if was loose aluminum or something.

 

[QUOTE=soundmike;6196358]I've noticed recently that at partial throttle right at 30mph i'd hear a slight rattle from the engine. I'm not an engine guru but wild guess is it sounds like something is turning faster than another part attached to it.

I can easily replicate it by going just beyond 30, letting off gas then partially pressing the pedal down again.

at that speed in a 6mt you would be going at about 1200 rpm or just off idle...do you hear this on cold start up? (Fram OIL filter is usually lthe culprit) but with warm engine and moving it sounds like a rod knock. check your oil dipstick...rub it between your fingers and look at the clarity of it...see any shiny particles? what weight OIL do you use...hopefully it is not 0w10 if so go to www.bobisthe oilguy.com

 

Uhmm . . . How can you possibly make that assumption if you don't know what gear he's in??

 

Does it do the same in neutral or only in gear?

 

I am trying to help here and since there is NO mention of what gear he/she is in I have to take a shot at 6th gear which means @2500rpm=60mph (30mph=1250rpm) in my car...the fact is most of these off idle knocks are worn connecting rod bearings usually from people to lazy to check their oil level...they only check it when it knocks and then they weigh in here asking what should they do when they only have one quart in the sump.

 

^^ Hey, the offer of help is always appreciated here, I didn't mean to imply otherwise (in case I had).

That being said, I can assure you that Mike is NOT that guy. He's very meticulous and spot on about his ride, always!

 

This situation is all to familiar for me with the other vehicles I've owned... The dealer on one occasion told me it was an exhaust shield issue. Any modifications made to the car that would alter the functions of the car? I noticed with the Test pipes and y pipe I hear a rattle and squeak of air at times.

 

No biggie The rattle is so easy to coax out of the car i can even tell before it happens that it will, although again it's very specific .. partial load, almost always at the 30mph mark.

It's only in gear. Neutral at any rpm is fine, so it's got something to do with engine load somehow.

Not a problem, any help and suggestion is appreciated. The oil is fine and every single UOA i have have come out pristine. Is it possible that it's not internal?

Often times the rattle reminds me of a friends (late 70's) Toyota, the rattle it makes at idle that goes away when you apply a little bit of throttle.

It's scary how much you know me. Meticulous to the point of nearly being OCD, i'm afraid. I check all easily-accessible fluids every week-end.

 

Sorry to bump this back up. I have to admit that other life issues have taken priority and have only been able to get back to this particular problem.

The rattle is still there, and still pretty much in the 30mph range. One thing i notice is if i drop it to 4th (5AT) the rattle goes away.

So my initial statement of it feels like something is turning faster than another seems plausible. Could this be a failing timing chain tensioner? It's supposedly not unheard of with VQ's (DE's, in particular) but haven't heard much of it happening on HR's.

Any further insight is much appreciated.

Thanks.

 

Is this only when the car is moving or when parked and revving too?

 

Just when moving at that speed and in 5th. Bringing it to 4th does away with the rattle.