What's whining noise under the hood??

Jat007 · Post by **Jat007** » 06 Jan 2014, 09:43

Greetings,

Today, the temperature at my location is -18 F at 8:00 AM.... My 2007 XC90 V8, did not start until I put the jumper cables on it for about 5 minutes... After the engine started, there was this long whining noise under the hood. I looked, but not sure if the noise is from the serpentine belt or something else.... The serpentine and and 2 belt tensioners have been replaced 2 months ago. The whinning noise does go away after 3 or so minutes.

Do you guys know what's whinning and why?

Thanks,

Jat007

Post by **kcodyjr** » 06 Jan 2014, 10:04

Sounds like you've been getting moisture in the air pump; assuming the V8 has one. It comes on for a few minutes at cold starts to warm up the catalytic converter. It's also the world's biggest pain in the ass due to the tendency of corrosive exhaust gases to take out the air pump check valve, which allows exhaust fumes to reach the air pump, which causes more corrosive condensation and takes out the pump motor. The saying is, in the winter, it's a water pump.

Also sounds like your battery is either not winter-spec, or on its last legs.

If you think the noise might be coming from around the belt area, squirt some WD onto the shafts, and/or some belt dressing onto the belt. It'll momentarily quiet it down.

Jat007 · Post by **Jat007** » 06 Jan 2014, 10:23

I forgot to mention that the Battery was replaced 4 weeks ago. According to Sears, the Battery is the recommended size & group for the XC90.

Thanks,

Jat

Post by **jimmy57** » 06 Jan 2014, 10:44

In really cold temps it is not unusual for power steering pump, auto transmission pump, and engine oil pump all to whine. If you heard the noise up front then that would be power steering pump. It is located up top in the V of the V8 engine.

When the oil warms and it thins a bit the pump quiets down.

Would the battery turn the engine over at all before you jumper charged it?

Jat007 · Post by **Jat007** » 06 Jan 2014, 10:55

Yes, the engine turned over several times before the battery got kind of low and all I get is the dome light and a few click, clicks. If I waited a few minutes, I have more response from the battery, but just not enough power to full crank the engine over. I had the engine running for about 10 minutes before I shut it off and put on the charger for the rest of the day.

Thank you.

Post by **jimmy57** » 06 Jan 2014, 11:48

Do you know what oil is engine now?
10W30 and 5w30 get pretty thick at -18F.
That in addition to weakened battery due to that temp can make it not turn over.
Block heater and battery warmer wraps/blankets are used in places where those temps are expected.
A tarp stretched over the front of vehicle with an electric heater on low (500W-750W) would make for a completely different experience. You have to be sure the tarp can't obstruct air flow into heater or be too close to heater. I stayed at a cabin in Colorado last year and did this. I used a metal dog crate with the electric heater in it and the tarp over hood and crate placed 2 feet from front of vehicle. This worked really well. I was worried as block heaters are usually 750 or 1000 watts.

Is -18F normal for winter temps for your area or is it an every 20 year thing due to the Polar Vortex?

You do not have an air pump.

Jat007 · Post by **Jat007** » 06 Jan 2014, 12:03

I used 5w20 M1 Full Synthetic. This is the coldest weather since 1996. We do get pretty cold here in Minnesota, but nothing like last night and today... I looked around, but I was not able to find any battery blankets or warm wraps from the local autopart stores. Maybe, I should look in Amazon...

Thank you for your time.

Jat

Post by **jimmy57** » 06 Jan 2014, 15:28

Your motor oil should not have been the problem but the trans oil pump and power steering pumps make every rotation the engine does and with even that synthetic oil getting thicker at that temp it is a lot of work for a super cold battery to turn an 8 cylinder engine over.