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Shrill noise after engine gets warmed up....

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After my engine runs awhile and gets nice and warm, maybe 30 minutes after a good hard run, I am getting a shrill noise out of the engine bay that I just can't isolate. It is either one of two things - either my new Delco-style alternator (new AutoZone Gold) bearings or , believe it or not, my valve springs have worn a nice imprint in the inside wall of my aluminum valve cover. That's right, upon cleaning the darn thing up, I noticed some distinct scoreing on the walls of the cover, just too snug a fit. I am guessing that when the engine gets hot, everything expands and thus contact. Surprisingly, the darn thing drops right on when installing it. Guess I need to pop it off and shave the inside. Could the alternator bearings, even new, be making the noise. An option is get the car up to heat then loosen the alternator to take it out of operation. Of course this takes the water pump out too so I would have a very small window of time to check it out, and it really only is audible while driving and under load. Go figure!

Bill
 
Bill, what about electric fan (I think thats what you have) or any of the pulleys rubing on anything or fan belt slipping,---throw out bearing or piliot bushing ,----rocker shaft or rockers, also make sure your crank pulley is not coming lose. Just some ideas, not knowing exactly what it sounds like.
 
I don't know Allan, it's just a high-pitched whistle sound. Not a TO bearing (clutch action has no affect), seems to rise and lower with rpm of engine. Very perplexing. Checked out everything, thought maybe alternator bearing, even though new, could be talking to me. Almost sounds like a air-inducted whistle though. I have so many extraneaous sounds with my car now (all the mods and ad-ons have their unique sounds) that through the cacophony of noises I just wonder if I am hearing things.

Bill
 
do you have a fan clutch?

mark
 
[ QUOTE ]
...An option is get the car up to heat then loosen the alternator to take it out of operation. Of course this takes the water pump out too so I would have a very small window of time to check it out...

[/ QUOTE ]

You should be able to make a belt that just operates the water pump -- I have done this on a 4 cylinder using a length of nylon rope (when the dynamo bearing went south).

It has a bit of stretch so you can get it tied tight enough to operate the H2O pump from the crank. I used about 1/8" rope/cord, don't worry about the knot, just trim the ends after it is tied. You should be able to drive for hours with this arrangement (I did) and rule-in or rule-out the alternator as the source of the noise.
 
[ QUOTE ]
You should be able to make a belt that just operates the water pump -- I have done this on a 4 cylinder using a length of nylon rope (when the dynamo bearing went south).

[/ QUOTE ]

Panty hose make a serviceable emergency belt, too.
Jeff
 
I had a similar squeal. I found that the metal fuel line that passes around the front of the engine had decided to rub against the water pump pully-ever so slightly but noisily. I was expecting the worst and as usual with the TR it was something simple. HTH
Mike C '71 TR6
 
[ QUOTE ]
It could be the water pump too.

[/ QUOTE ]

Hi Bill,

Is it your turbo kicking in? /ubbthreads/images/graemlins/wink.gif

Seriously, I had a similar noise in my Land Rover, that began happening right after picking it up from dealer warranty servicing. It only occured when fully warmed up and even then was somewhat intermittent (took me three tries to get it to make the noise when the dealer's mechanic was around).

Turned out to be something loose in the cooling system that had floated around until it got caught behind the water pump impellor. If it had been me, I'd just have removed the water pump and removed the offending scrap of gasket or whatever. The dealer was responsible though, so they just replaced the water pump under warranty.

Just one possibility, that would be pretty easy to check/repair.

P.S. Just thought of another water-pump-related possibility... have you replaced WP or its pulley lately? The repro pulleys available today tend to rub on the housing of the water pumps. Usually this is pretty obvious, but it might be a case with very close clearance when cold, that starts to rub lightly when warmed up.

/ubbthreads/images/graemlins/cheers.gif
 
Not yet. I just closed it in the garage and hope it goes away. Too many honey-dos to get out of the way before I get back under the bonnet. She has bees in her bonnet and I need to let everything cool down a bit. Women don't understand. Will keep ya'll posted.

Bill
 
Can't hurt. Actually, I am using a cogged fan belt. Seems I read somewhere that this is not as good as a solid, un-cogged V-belt. What's another ten bucks....

Bill
 
My bet is a junk alternator, sure its new and shiney, but do you really think that the trained monkey that assembled it used grease???? If you do, I have some swamp land that you will love.......
MD(mad dog)
 
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