Maybe a stupid question? Engine noise...

[scottellis88]

I am sorry but this may be a stupid question to some but i have always wondered what it is.
When starting my car for the first 10-15m my car sounds like theres a lot more going on under the bonnet? Sort of like more turbo more air flow etc.
It is not a bad sound like engine rattle etc but just more powerful if you like.
After a short distance it goes away and the hilux goes back to normal.
What is happening in this stage?
I have heard other 4wds such as a mates "4wd" pathfinder (put in commas for a reason haha) which sounds like that at all times. Just wondered why mine is only at initial startup

[Cobba7490]

I'm no expert by any means, but my missus' Mazda 6 sounds similar to what you're explaining first start up of the day too. I've always just thought it was cause the engine was cold and stuff. Obviously that's a petrol, but i don't think it's anything to worry about

[HK1837]

Sounds like a good old fashioned choke to me! I know this is done electronically today but back in the day when we had manual chokes (ended with 6cyl HZ Holden and VB Commodore in GMH stuff) that was essentially as you state. I recall blokes pulling the choke on in their old 6cyl Holdens to make them sound like the engine had a lumpy cam. Even automatic mechanical chokes which we had up until the end of VL Commodore and Calais behaved similarly.

[Phrancis]

Maybe the cooling fan.

[Gipsy]

Just as hk1837 said... Most likely electronic'choke' overfuelling to warm up, modern engines just add more fuel to warm up which is essentially as the old 'choke' did. 10_15 minutes (I presume) is coincidence with engine temp... Check temp gauge when it does it, probably stops when engine up to temp.

[hiluxxury]

Maybe the cooling fan.

Yep, could be this as well before the fluid warms up.

[Gipsy]

Methinks not the fan, as fluid gets hotter the fan is driven harder, that's how a viscous fan couple works

[scottellis88]

Yeah it only lasts for 10-15meters i can make it to the end of my road then it stops

[Gipsy]

Manual or auto? It may also be the auto transmission fluid pumping into the torque converter after draining whilst stopped.

[scottellis88]

its a manual mate, its happened since day one so don't think anythings wrong i just wondered what it was
i kind of like the sound of it too, id be happy if the lux always had it

[bloke&tackle]

Maybe the cooling fan.

Yep, could be this as well before the fluid warms up.

Correct, it is a characteristic of fluid fan hubs, they drive for a minute or so when stone cold, then freewheel during normal driving. Not a deliberate design feature, just something that happens