noise/vibration at 2500 rpm

[cj71z]

Well my car sat for a month and when I went to go to work the other morning while I was accelerating I heard a new noise that wasn't there before. I took it out today and figured out it happens at 2500 rpm no matter what gear. I get an odd sound(a low drone), and a slight vibration I can feel in the shifter, and the pedals. Any ideas? I know my throwout bearing is going because it's making noise, could it be getting worse?

[beandip]

generally a throwout bearing makes noise only when the clutch peddle is depressed . This ''drowning '' sound , could it be the engine fan spinning because of a locked up fan clutch ? Have a look at that. If I can think of something else I will post it . Simply having the car at rest for 30 days shouldn't have effected any thing but the battery . Because the sound is rpm effected only leads me to question the fan clutch . usually a water pump problem starts with a shaft seal leaking . How about the alternator , if you have a long screw driver , with the engine at idle touch the casing of the alternator with it and put the handle to your ear and listen for bearing sounds . Gary

[cj71z]

water pump and alternator are both new, I am concerned about the fan clutch, but wouldn't it make continue to make noise no matter what the engine speed? This sound goes away right when I pass 2500k. Can loose valves cause this? I thought I read something like that on Zcar.com, but can't find the post now. I was also thinking about the harmonic balancer, do you physically inspect it to see if it's separating or do I have to take it off? The one thing I forgot to check is if the sound goes away when I engage the clutch at 2500k. I'm thinking that if it does then it could be the TO bearing.

[KDMatt]

Is it possible that you leaked some lube from the tranny?

I would think that if your tranny fluid level was sufficiently low it would cause a droning sound as well. You could have also accumulated some moisture in there too, I mean it did sit for 30 days right?

[beandip]

The fan clutch , mine does this , has the fan running at engine speed for a short while when I first start the engine in the morning. It will sound like a muffled roar . This will not continue for more than a minute or so , and then it will spin freely if I raise the rpm to anything above 1000 or so . Once the engine has been running for two to three min. the clutch allows the fan to more or less free wheel . At least it is no longer keeping up with the engine speed . Since you suspect the throw out bearing is faulty , if this is so do you hear the sound when at idle and you depress the clutch ? And then while stopped rev the engine up slowly to 1500 rpm or so with the clutch depressed ? Unless you have been in deep water , like a foot deep or so , I doubt vary much there is any moisture in the trans. Normal maintenance of all fluid levels is expected . GARY

[cj71z]

i recently changed the trans oil about 2 months ago, and I don't see any leaks so I'm assuming it's still full. My trans makes noise when at idle with the clutch released in neutral. This sound goes away when I depress the clutch. Does this sound like the TO bearing? I'm going to replace the fan and the clutch in the near future with the plastic one. Beandip have you ever heard of loose valves causing a vibration? The last thing I did before I let it sit was to adjust the valves. I followed the directions and all were at hot spec. Now my valves are clacking pretty loud, but I heard they can get like that on an old head so I didn't worry.

[beandip]

Do you have the '70 metal fan ? If so by all means change that out and in the mean time check it over vary closely . They can come apart and eat the radiator and or your hood . Especially if the clutch is locked up. No I have never heard of a valve adjust causing what you are describing . As to the noise of the valves . Is this a stock cam or a aftermarket ? Some times a regrind will cause some valve clatter . However it does not come on later , usually it is there from the get go. The car setting for 90 days should not have any effect on the car , unless you have some vary old tires that get flat spots when they set for a long time . But that will go away when driven a block or two . I am out of ideas . Gary

[Mat M]

Your sig states that you are in the "bay area." Is that the SF bay? If so, if this were my car, I would take the metal fan off the car immediately. The bay temps don't get too high, IIRC.

I have had a droning noise from a 4 cyl ford I have, it turned out to be the heat shield vibrating at one certain frequency, no other time. Have you checked all the fasteners around the engine bay?

[cj71z]

yeah I'm from the east bay to be exact, here we have cool AM temps, but sometimes during the day it can get 100+. Going to take off the metal fan when I get the setup I just won on ebay. I've been kinda worried since I changed the waterpump because the fan has a little play. If the vibration is from the fan then hopefully it'll disappear after I change it out.