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HELP- Loud propeller sound when I start the car

10K views 19 replies 4 participants last post by  sangmarie 
#1 ·
I am not mecanically inclined and frustrated because I took my '04 Forester XS to the auto shop for them to check a loud sound coming from under my hood. When I start the car it sounds like a loud propeller. Once the engine is warm the sound isn't as loud but can still hear it especially when I accelerate. The mechanic is baffled and has no clue where it's coming from. He assured me its not the engine or transmission.... ?!?!?! Not sure how he can conclude this if he doesn't even know why it sounds like a prop plane.... Any help would be greatly appreciated...:eek:)
 
#2 ·
Here's a guess: how are the belts? Any chance that the belt is coming apart and slapping against something until the engine comes to temperature????

Just a wild guess.....

Steve

Suggest that you open the hood and stand there while having someone start the car....you should be able to localize the sound.
 
#8 ·
it would be pretty easy for the mechanic to take the drive belts off to rule out power steering pump, a/c compressor, alternator, and idler pulley bearings.

could be a timing belt idler or the tensioner if those weren't replaced during the timing belt job. the noise for those would still be there if the 2 normal drive belts were removed.

about how long (time, miles) has the sound been there and does it seem to be getting worse quickly or gradually?

what brand and weight of motor oil is in your car? is motor using any oil between changes?



you can look at youtube for a variety of sounds and the comments people make about them and compare to yours.

 
#9 ·
Wow, you are awesome! The YouTube clips really helped. The obnoxious noise coming from my car sounds just like the belt tensioner clip. I need to change the timing belt 10k from now. Should I just have it replaced now or can I continue to drive it? Again, don't know much about cars but is it normal practice to replace the tensioner and/or belt idler when replacing the timing belt? What do you suggest?
 
#10 ·
Well, there are different opinions and thoughts. A lot of people cheap out and only replace the timing belt and perhaps an idler if their mechanic suggests it at the first replacement (105,000 miles or perhaps a little sooner). This is fine if you want to sell it before say 150,000 miles or something. If the belt only is replaced then there is a very good chance at least one pulley or water pump would fail before the timing belt really needs to be replaced again. Also perhaps not quite as big a deal if you don't take the car on trips and are really "tuned in" to the noises it makes and would notice something wrong.

At your mileage and if you want to keep the car for very long, you should go ahead and do the "major" timing belt service which would include the tensioner, all the idler pulleys, new water pump, and re-sealing the oil pump (plate on back tends to loosen over time). Also should probably go ahead and replace the oil seals on the front of the motor too at that mileage.

Keep in mind if the belt breaks or slips that the motor is an interference engine, meaning valves will likely be bent or other expensive damage occur!
 
#11 ·
After reading you post this afternoon decided to drop my car off at the auto shop to have the timing belt(water pump and tensioner) replaced. The first time I had the timing belt replaced was in '07 at 90k so it's due to be changed again. Do I need to specify the pulleys and the other things you mentioned as well? I really do plan on keeping my car for awhile... it's been so good to me even at 170K. Have had no major problems with it up til now.

Again, so appreciate the your help. Thank you so much:icon_razz:
 
#12 ·
i know it's spendy, but if you really want to keep it at least another say 60,000 miles or more i would do everything now and be done with it.

i'm a little concerned your mechanics don't know subies that well, though. if you have done a lot of business with them over the years and are having them look at your A/C too they should be willing to take off the drive belts and do a little diagnosis for you to be sure of the problem before just doing all that expensive timing-belt related work.

good luck!
 
#14 ·
i think it's a good idea to do the timing belt and other components. i'm just saying that it would personally make me feel better that the shop really felt like that would fix the problem before i spent the money.

i also thought that it would be good if they took a close look at the headgasket areas to be sure no leaks were evident before fixing. 2003 and up are somewhat more likely to leak oil or coolant externally than have a more typical internal leak ("blown headgasket"). i just had headgasket done on my '04x at 86,000 miles. i believe some here have done a lot of miles and not had that happen.

the biggest thing is feeling like you can trust your mechanic to find the problem and fix it and not ignore anything likely to cause a problem soon thereafter.
 
#17 ·
if the head gasket areas don't have oil or coolant residue then there is no reason to do them.

even if they do have minor residue if you haven't noticed any drips or bad smells, they you should be OK for some time. imho it's something for a mechanic to keep an eye on at oil changes so hopefully you have some fair warning if it is required.

if you have maintained the car well with regular oil and coolant changes then hg issues are less likely to occur or may take longer.
 
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