Hi, I posted earlier about taking my car to Midas for an oil change and leaving with a new starter and battery…along with a screeching sound after engine turns over. I received lots of great input about serpentine belt, fly wheel so thanks a lot. Problem is that I have taken the car twice to the dealership but the sound doesn’t happen all of the time and they are not able to hear it and thus work on it. Any ideas why this happens? It is, after all, not a subtle sound! I am almost too embarrassed to keep taking it back to them. Thanks again for any future advise.
Shirley
Does your car have a serpentine belt that drives everything or does it have a separate alternator belt? If it has a separate belt, it could be loose or you could have been sold a belt that was almost right.
If it’s a loose belt you probably won’t hear it if the engine is hot. Does it happen more first thing in the morning? If so you may need to leave it at the dealership over night.
If the starter was not shimmed properly, it will stay engaged with the flywheel. Now the motor will be driving the starter and it will scream!
Do you usually hear it first thing in the a.m.? That would normally be when an alternator would be working at full capacity and pulling the hardest.
Even though it doesn’t happen when the shop is looking at it, the serpentine belt and the tensioner can be checked for proper tension and for evidence of slippage. Slippage will form glazed spots on the belt. The belt itself can also be checked for evidence of needing replacement by checking for cracking of its ribs where it bends backwards around the idler and/or the tensioner pulleys.
As to the starter shimming problem referred to, generally that’ll manifest itself as a high frequency whirring sound…but one man’s whirring is another man’s screeching. It is a possibility. If you can have a friend start the engine while you listen under the hood you might get a real good clue as to whether that’s the source…or wher else it might be coming from.
There could be a problem with the bearings in the belt tensioner.
I should clarify because a few of you have mentioned the timing, it is not necessarily at any time. At first I thought it was after driving the car for some time, then turning it off and turning it on again would produce the sound…however, it doesn’t happen like this all of the time. I haven’t noticed it more first thing in the morning. It is really sporadic.
Good point. Or, for that matter, any of the other belt driven components.
The best way to check them is to remove the serpentine belt and try turning and wobbling each one by hand.
I agree that the problem may be the starter. The problem, according to the OP started when tbe starter was replaced. Furthermore, Midas is probably not the best place for this kind of work. Much of the work at Midas is exhaust systems and brakes. The starter may not have been shimmed properly or there is some problem in the starter drive.