2004 Volvo XC70 Whistling Noise in Heavy Rain

My XC70 makes a weird whistling type noise in heavy rains that last a long time. It doesn’t do it in light rains, or rains that are heavier but don’t flood roads or collect water on the shoulder or slow lanes, only the really heavy, hard to find the road type.

There are no warning lights when it happens, turning off everything, except the car and windshield wipers, doesn’t help. Pulling off the road, helps after about 30 seconds, but then we start again, and it continues. This is only happening during really heavy rains, is scary, and I don’t have a clue what it’s doing or why nor does my mechanic.

Help please, and thanks.

I am wondering if an accessory drive belt is getting wet.

A test for this would be to wet the windshield, start the engine, turn on the windshield wipers and head lights, wet the accessory drive belts with a spray bottle filled with water, and see if the noise appears as the engine is reved. If this is the case, inspect the bottom of the car for missing or damaged engine shields and/or replace the accessory drive belt(s).

Hope this helps.

In a very heavy rain, if your wipers work, and motor keeps running just keep driving. I don’t think you have a big deal problem here.

I’ll check the accessory drive belt and hope it’s a simple fix, if fix is needed. As for not a big deal problem, yay I sure hope you’re right. I had the car inspected by a Volvo dealer when I bought it and they found nothing wrong with the engine shields, but they could miss that easily enough. Thanks.