Deep exhaust sound passenger side / Engine revs questions

[Hodge]

Thought I'd ask within one thread, instead of creating separate ones.

Ok first of, I noticed this when I bought the car, but never really paid much attention to it. Today a workmate noticed it too, and suggested it's very unusual so thought I'd ask.
When in the car, especially when in passenger seat there is a deep, booming drone sound. Hard to describe, it's like being in a tube of some sort, with a very large diameter V8 exhaust being right there in your face. Now obviously the exhaust is right on the other side of the footwell / firewall. But this seems like it's louder than it should be. Goes away with a tad higher revs. Any ideas?

Secondly. You step on the clutch, put it into gear, but leave clutch depressed, do your revs drop a little? My D22 used to do this but not the patrol. Another thing was that if my navara was moving in neutral, the revs were a little higher, as soon as you stop, the revs go down to idling level. Once again patrol doesn't do this. Is this normal for a my model / year of patrol??

Thanks ahead for responses!

[Drewboyaus]

On the noise front, have you got a snorkel?
Mine (and yes I have a TB42 petty Gq) has a snorkel on the passenger side and when I have the passenger side window down its like my special window into the engine.....the induction noise is awesome! It just makes you want to keep your foot up it...
If you have a snorkel, it might be the induction noise from there.....


Tip tip tip......tap tap tap....

[GQ TANK]

It could be a exhaust leak - I have one at the flange (going to replace the gasket tomorrow) defiantly can hear it inside the truck

[threedogs]

If fitted with a snorkel they are known to create a noise,
as for clutch when depressed you shouldn't be creeping forward

[Hodge]

Hey fellas thanks for the reply. Noise was there pre-snorkel. My snorkel got fitted last week and I've had the car for a month and it's been doing it ever since. May be exhaust leak. Will find out once my beaudesert gets fitted.


If fitted with a snorkel they are known to create a noise,
as for clutch when depressed you shouldn't be creeping forward

Hey td. The car does not creep forward. Ok picture this. You're in the car, the car is idling. You step on the clutch and put it into any gear. As soon as you put it into gear, without releasing the clutch (your foot is still down on it all the way), do your revs change at all ?? What I'm saying in this scenario my Navara used to drop revs a tad, Patrol does not, it keeps the revs level regardless.

[threedogs]

But they are Drive by wire[Patrols]
Could be a dirty sensor somewhere?
Weird
May also be leaking exhaust manifold or EGR,
Might be worth blocking EGR when fitting new ehaust

[Alitis007]

Pressing the clutch can some times make the crankshaft move coz you are taking the load off the back of the motor, so its nothing to worry about. It could also mean the thrust bearings on the crank shaft are better in the patrol then the navara so thats a good sign if you think about it.

Drone from the exhaust, sometimes if the exhaust is bent and touching somewhere or if its too rigid can make that sound. You are replacing it so again dont stress about it untill you fit the new one. If its still there with the new exhaust ( and this is in extreem cases) a possible collapsed engined mount thats not cushioning the engine vibrations. This might not be the case of yours Eric but wait till you fit the new exhaust and see how you go mate.

[Hodge]

Thanks George and John. Will see what happens when the exhaust goes on.
As for the revs thing. Could someone with a similar model to mine please confirm that these new CRD's do infact drop revs when put into gear.
Could this be a neutral position switch problem? I know this was common on the D22's and does have the symptoms of what i'm describing.

[mudski]

My 3inch redback system drones at 2400rpm. Anything higher or lower it doesn't do it. Check it for leaks, other than that I wouldn't worry.