Engine is cold it makes a loud noise that sounds as if a fan is hitting something?

Hi,

It's interesting that it goes away when it warms up. Do me a favor. Open the hood and check the cooling fans to see if there is evidence of the fan touching the fan shroud. If you look at pic 1, it shows what you are looking for. When you open the radiator, the fan is located between the radiator and the engine.

Also, if it's possible, please record the sound and upload it for me to hear. Hopefully, I'll be able to recognize it.

Let me know what you find or if you have other questions.

Take care and God Bless,
Joe

Hi,

I did hear it. It didn't last too long, but I did hear it. Does the sound seem to be more toward the front of the engine. When I say front, I am referring to where the serpentine belt is located. Also, please make sure the engine oil is clean and full. If it is low, it could be the cams and lifters making noise until oil gets to them.

If it seems louder there, it sounds like it could be a water pump or one of the belt-driven accessories. If this is the case, if the serpentine belt is removed, you could start the vehicle cold for a few seconds to see if the sound is gone. I'm thinking it could be the water pump because I heard a small amount of belt squeaking. That happens if the belt gets contaminated with coolant. Have you noticed if the coolant is getting low or anything under the vehicle?

I don't know if you are comfortable doing this, but here are the directions for removing and replacing the serpentine belt. Only do this if it seems as if this is where the sound is most prominent. The attached pics correlate with the directions.

_____________________________________

2012 Nissan-Datsun Altima L4-2.5L (QR25DE)
Removal And Installation
Vehicle Engine, Cooling and Exhaust Engine Drive Belts, Mounts, Brackets and Accessories Drive Belt Service and Repair Removal and Replacement Removal And Installation
REMOVAL AND INSTALLATION
DRIVE BELTS

Removal and Installation

REMOVAL

1. Remove the fender protector side cover RH. See: Front Fender Liner > Removal and Replacement > Coupe (Coupe models) or See: Front Fender Liner > Removal and Replacement > Sedan (Sedan models).

See pic 1

2. Securely hold the hexagonal part in pulley center of drive belt auto-tensioner, move in the direction of arrow (loosening direction of tensioner) using Tool.

Tool number: - (J-46535)

WARNING:
- Avoid placing hand in a location where pinching may occur if the holding tool accidentally comes off.

CAUTION:
- Do not loosen the auto-tensioner pulley bolt. (Do not turn it counterclockwise.) If turned counterclockwise, the complete auto-tensioner must be replaced as a unit, including pulley.
3. Insert a rod approximately 6 mm (0.24 in) in diameter through the rear of tensioner into retaining boss to lock tensioner pulley.
- Leave tensioner pulley arm locked until drive belt is installed again.
4. Loosen drive belt from water pump pulley and then remove it from the other pulleys.
EM

INSTALLATION

1. Install the drive belt onto all of the pulleys except for the water pump pulley. Then install the drive belt onto water pump pulley last.

CAUTION:
Confirm belts are completely set on the pulleys.
2. Release tensioner, and apply tension to drive belt.

WARNING:
- Avoid placing hand in a location where pinching may occur if the holding tool accidentally comes off.

CAUTION:
- Do not loosen the auto-tensioner pulley bolt. Don't turn it counterclockwise. If turned counterclockwise, the complete auto-tensioner must be replaced as a unit, including pulley.
3. Turn crankshaft pulley clockwise several times to equalize tension between each pulley.
4. Confirm tension of drive belt at indicator is within the allowable use range. See: Drive Belt > Procedures > Checking.
5. Install the fender protector side cover RH. See: Front Fender Liner > Removal and Replacement > Coupe (Coupe models) or
See: Front Fender Liner > Removal and Replacement > Sedan (Sedan models).

___________________________

Let me know.

Take care,
Joe

Hi,

You are very welcome. If you have the chance, let me know what you find or if you have other questions.

Take care,

Joe