I recently purchased a 2004 G35 sedan (5AT). It's seems to roar (loud noise) off the line when you first start it and has very little low end torque at first. After doing some research and better understanding my car I think I am figuring out the noise I hear. My car has a belt-driven cooling fan. I just had the cooling fan assembly replaced when my mechanic told me the old one was wobbling and needed a new fan clutch.

From what I have read Nissan did away with the belt driven cooling fan around the middle of 2004. It really seems to rob my car of initial horsepower and that fan really roars when you first start the car and take off in first gear as you rev the engine. I thought there was some sort of mechanical issue but apparently that is just how it operates. Slow and noisy!

I am not a mechanic (other than doing oil changes and minor repairs) but I wonder what the possibility, expense, and difficulty would be of converting my G35 to a dual electric cooling fan system?

Anyone else with an early G35 sedan have the same issue?

 

It's been done several.times. search and I am.sure you will find something about it. You won't gain much power, around 5.

 

You need to drive another car and compare.

 

Could be the sign of a failing fan clutch too. Replacing it might solve your issue.

Check to see if it's hard to turn when the car is cold and engine off

 

Our cars due not let you use all the power it has until it reaches operating temperature to prevent engine damage. You will notice alot of people take it easy on there cars until they warm up, and thats why you notice a lose in power at firsts and not later when the car warms up.

 

Who floors their car when it's cold........... That's just horrible and careless. Poor G

 

The fan clutch has been replaced. The entire fan assembly was just replaced. The more I drive this 2004 Infiniti the more I wonder about how it operates while cold. I never floor the gas pedal on a car even if it's at operating temp. I've never red-lined any car I have owned including BMW's.

What I am wondering about is how my 2004 G35 shifts from 1st to 2nd when it is cold. It is a very slow upshift that creates higher revs/RPM's in the engine and is somewhat loud as it shifts from 1st to 2nd. It gets better when the car warms up. Is this normal? Or is this a transmission issue? I've never owned a car that upshifts like this and causes a higher revving engine noise when cold.

I always allow my cars to start the idle down to lower RPM's before I even drive it. But in this 2004 G35 it still has that louder engine revving shift from 1st to 2nd then it quiets down and shifts fine through the other gears. Even when it warms up the shift from 1st to 2nd seems to rev the engine higher and creates a louder sound from the engine.

I'm thinking about having a transmission specialist look at it this week. My 2007 G35 doesn't do this and the 2005 G35 I test did a test drive with didn't seem to do this either.

 

So, is this what is creating that higher engine rev I hear and slower shift from 1st to 2nd when I frist start the car? It sounds almost like I have it in neutral and I'm revving the engine......but the shift is smooth from 1st to 2nd. Just loud and slow.

 

the car doesn't 'limit' engine power when cold, but it isn't wise to get too throttle happy until the engine is fully warmed.
I haven't driven one of these cars with the belt driven fan, but with other cars I find the fan clutch seems to fully engage when you first start from cold, then after about 60seconds, it starts to release, then it should engage again when the engine gets hot and needs extra airflow.

Remeber your transmission will operate a bit different when cold, usually the TCU will shift at higher RPM, and shifts will feel different when the fluid is cold.
But it shouldn't 'slip'. If you need to rev the engine to 3000rpm before it starts to move.. something is wrong.