wtc88c

Having bought my 06 GX 470 only a few months ago, we're encountering 90-degree-plus days for the first time. There is an unusually loud noise from the engine that I'm almost sure is cooling fan noise. It occurs after running in the heat of the day. It's not mechanical noise, but a loud roar like that of a large truck engine.
Is this typical for these models in the heat?
Does anyone know of a fix for this? a quieter fan, etc?
Thanx,
Bill

habeeb89

iTrader: (3)

I am pretty sure that it is the cooling fan constantly turning on, you have to remember that the GX is no small SUV. That V8 will heat up and quick. On my GS430, the fans always roar on every few minutes and that is a smaller V8 than yours...

As long as the coolant is fresh and the temp. gauge on the instrument cluster is in the middle, you are fine.

Linko

It is the cooling fan, and yours sounds very typical for summertime in the South. My GX does the same thing, but I usually don't hear it unless I am outside the vehicle or at a standstill. There is no fix - the engine needs a big fan with a lot of air circulation power to keep cool.

The G Man

Thats normal, the GX has a cast iron block, it needs a lot of cooling.

snhrph

You can turn off the AC to reduce the fan noise.

gsobol

It's a mechanical fan, ie it's always spinning. The only thing that controls the speed is a thermal slip clutch. If it's hot outside the clutch will engage sooner and stronger (less slipage) and it will allow the fan to spin along with engine RPMs producing more air movement and noise. It will also rob more of your engine HP in doing so.

I6turbo

iTrader: (1)

If it really seems abnormally loud compared to other vehicles, you should check (or have someone check) the fan clutch. I live in Florida and I've never heard mine making an unusually loud roaring sound. Typically the "large truck like roar" is caused by the fan clutch being fully engaged and causing the fan to spin a a much higher speed than it normally would for a given engine RPM. I've had other vehicles with a failed fan clutch (locking up too much) and they roared in a manner that I'd describe as you have here.

wtc88c

Thanks for your feedback.

mann777

My LS 94 came with a dual fan, later models came with Single Fan, There is lot of place where you can have a dual fan fitted on the GX. This improves the cooling efficiency by at least 5-8%. All you need is Additional Fan, Relay switch and a heater fuse

btle29

I have the same problem on my gx470. I contact the dealer and they told me that cause by a bad fan clutch, it's very common on the gx. The part is about $225. it's very easy to fix it yourself.

oardila99

My GX sometimes does the same thing. It roars like a BIG TRUCK coming up a hill in first gear.

Most of the time this issue does not present, however I have noticed that If I accelerate hard, reving up the engine, it starts roaring, and the roar doesnt quit until the car is turned off and it cools down. This is consistent with what is being said around in this thread as the fan clutch being the cause. It makes sense that if it engages when it needs to (during hard accelerations) but it is faulty and doesnt desengage, then the roar will persist. In addition, I have noticed that the car does not develop the usual power when it is roaring, thus it must consume even more fuel (it is a real fuel sink on its own).

My GX roars when I first start it, and continues like that for a couple of seconds when I start moving, then it quits, however the roar comes on and persits when I accelerate hard. This indicates that when the vehicle is first started, the clutch is probably engaged, and disengages when the vehicle moves and the engine cools with the incoming air, and that the clutch fully engages again if the engine is reved up. So... if your roar goes away after you start the car, try not reving it up so much during your driving, at least while the problem is fixed. If your fan clutch just does not disengage, and the GX just roars all day long no matter how you drive it, then it might be worth to caugh out the $225 and replace the thing.

By the way. I first noticed the roar after having to cross a really deep river, in case there is a correlation.

OA

JZZFZZ

It is funny I noticed cooling fan noise the first time 5 month after I got it. I turned the truck on in my garage with garage door closed. It was crazily loud. Worrying this was not normal, I turned on my Tundra, it was as loud. I then turned on my LS430, silence.

These trucks are crazy.

Has anyone thought about doing anything about the fan noises?