Cold start whine, doesn't go away till warm. Help!

M

mctwist77

Member
Location
Mississippi
Car
2004 FX45
Hey everyone, I have a 2004 fx45 with 137,000 miles, and as you can see by the title of the thread I'm having an issue with a whine noise coming from the engine bay area and it lasts for about the first 5 min of driving. So far I replaced both tensioner pulleys and the idler pulley and no luck. The car is not leaking anything. I was thinking maybe power steering pump on the way out but I'm not sure. Any help would be appreciated.
 
Could be the alternator bearings. After a cold start the alternator is working full load to bring the batttery back. Once it does the load goes down to a level just enought to run the rest of the vehicles DC loads.
 
I solved the same problem! Alternator has 2 bearings. I suppose you should replace both of them. I visited many auto repair stations. They didnt found a problem with alternator and they said that bearings are ok!! but i ordrered to replace them. And disgusting sound was stopped. Alternator stucks periodically because of back (rear) bearing. And its almost impossible to diagnose!
 
I didnt do it by my hands. I went to repair station. IMO the most difficult stage is disconnecting (and then connecting) alternator. To take alternator to pieces is not difficult! But you have to take special tools like press and remover (puller). Sorry 4 my english.. I dont know accurate names of tools on your language:disapointed:
 
I know I am going to get shot for saying this but, take the belt off and start the engine and see if the noise is gone. Dont drive the car! But DONT LET THE ENGINE RUN FOR MORE THAN 15-30 SECONDS OR HAVE SOMEONE ELSE START IT WHILE YOU HAVE THE HOOD OPEN AND LISTENING! Then shut the engine off immediatly! With the belt off you wont have jacket water circulating thru the engine! The battery should be able to run the engine for a few minutes and shouldnt be a problem. I disclaim any responsibility for any dammage that may occure. Lets see what some other folks have to say before you do this! I am a retired engineer with 44 years in the OEM engine business but I am not a Infiniti expert!
 
Well I am going to take the power steering belt off then run the engine. That way if there is no noise with the power steering disconnected then I know it's on the main drive belt, most likely the alternator.
 
Took the ps belt off and the noise was still there. I'm pretty sure it's the alternator because when I spun the alternator by hand it made some noise. I went ahead and ordered a Denso replacement alternator, got it for $270 shipped. I'm going to put it in next week. I figured I have 137k on the original alternator so it would be good preventative maintenance anyway. I'll update once I install it.
 
Update. Put a new alternator in today. No changes in the noise. It's a startup whine and lasts about the first 5 minutes of driving. It's on the main drive belt. Could it possibly a water pump?
 
Buy yourself a mechanics stethascope, when the car starts cold use it to listen around on the tensioner and a/c etc. (Dont let it hit moving parts because its super hard on the ears.) When you removed the main belt the noise is gone when the engine was running? Im a mechanic by trade and deal with a lot of noise coming from engines and the stethascope is my tool for finding the noise, Or use a long screw driver and put your ear on the end as you move the opposite end around on different spots.
 
When you start the car with the belt off it will throw some dash lights. Dont run the car for a long time just a min or two. Once you reinstall the belt the lights will go out.

Keep us posted as everyone likes to hear the results.
 
prelude48 said:
When you start the car with the belt off it will throw some dash lights. Dont run the car for a long time just a min or two. Once you reinstall the belt the lights will go out.

Keep us posted as everyone likes to hear the results.
Click to expand...
Yes, removing the belt for a short period of time is what I mentioned to him in my post on 11/24!
 
Ok, little update. Bought an automotive stethoscope and based on what I could hear through the stethoscope Im 95% sure its coming from the Idler pulley. This is weird because I replaced the whole idler assembly back in March. Has anyone else experienced a short life span on the idler pulley. Since I replaced it I probably put about 10,000 miles on the FX. (Back and forth to Texas)
 
Some things fail even if there new, Depends on the maker like if its oem or aftermarket, and other times its installation or over tightening the belt or whatever etc. Where i work we replace a lot of idler pullys on gmc's, its better then a a/c compressor or alternator( but i guess you already did that)

Just replace the idler, adjust the belts properly and enjoy the silence on cold starts.
 
You must log in or register to reply here.
Back
Top