Engine squeals when first started each day

When starting our van, it squeals horribly loud for about 10-30 seconds. Afterwards, it stops and doesn’t squeal for the rest of the day (most of the time).

This has been going on for a couple of years. I had the belts changed a few months ago and there was no difference. Any ideas on what this is and how to fix it?


Remove the belt and start it and see if it squeals…Also, you could check the battery voltage before you first start it. It should be 12.4-12.6 volts. If you find it below 12.0 volts, a parasitic drain or a bad battery is the problem…

You might want to have the condition of the battery checked out by having a load test performed.

When the engine is first started, the starter draws a lot of current from the battery. It’s then the job of the alternator to replenish the current that was used to turn the starter back to the battery. If the battery is deeply discharged while turning over the starter, it causes a greater load on the alternator to replenish the battery. This greater load on the alternator can cause the belt to slip causing the squealing sound. Once the alternator replenishes the battery where load on alternator is reduced the squealing stops.

If the battery is over five years old, have it tested.


You my also wish to check the belt tensioner.

The tensioner was my first thought as well.

Let me suggest that you start it some morning with the hood opened and someone’s head under it listening. If the bearing on the alternator is going, the AC compressor, or any other belt driven component that could be the source also.

This used to almost exclusively be the water pump when this sorta thing occurred. Now it can be idler pulleys …tensioners.

Take off the belts and check all of the usual suspects to see that they rotate by hand and don’t have any runout when you spin them. Apply force attempting to deflect them off plane.

I’ve had bad tensioners before, but they didn’t result in belt squeal as you describe it. They would result in “bird chirping” and in one case under charged the battery. It stayed functional, but was always low …causing the alternator to remain at high drag/demand …which caused more bird chirping. It also resulted in a hesitation off idle that I thought was inherent to the engine.