Noise at start up

[Ralf]

About 70% of the time when I start my 2014 it is absolutely silent, so I have to check the screen to make sure it is running. The rest of the time there is a rumbling/growling noise that sounds like it is coming from right front of engine compartment. Two different Ford tech guys say the sound is normal, depending on weather, etc. It only happens the first time I start, after running and shutting off, it is silent. Usually it goes away quickly, but yesterday it continued for several minutes. "Coasted" down the road for a couple of blocks until it was silent. On a few occasions it did start silent, but shortly the noise began. First hybrid I've owned, so pretty clueless about this. If there was a transmission fluid dipstick I would check that. Any suggestions?

[Bill-N]

Is this not simply the engine running?  Whether or not the engine runs at start-up is (mainly) a function of the HVB (high-voltage battery) state of charge.  So if the HVB needs charging when the car is started, the engine will start so it can recharge the HVB.

[Ralf]

Not sure. Last week it started silent but after about a block the noise started, it has happened before. Have noticed that battery icon shows low at start up, but I don't use it every day. Got hybrid to save on gas, but pretty much clueless about how they work. Miss my '93 Escort wagon, manual, w/40 mpg on highway. Great for road tripping & camping.

Edited September 5, 2022 by Ralf
add usage info

[Lacienega]

I would say it's normal. When it's colder or the hybrid battery is low, the gas engine will start - and because the engine is cold, it makes more noise/rumbling than a warm engine. The car doesn't start in electric mode always.

[VTCAPAgirl]

I bought my 2013 C Max used with 55,000 on it less than a year ago. Shortly after I bought it I noticed an irregular rumbling sound that comes from the right engine compartment most times I start it. It tends to go away after I’ve driven for a mile or so. My mechanic tried to reproduce it to diagnose, but couldn’t.  It’s louder, more pronounced and lasts longer when the weather is cold and I have the heat on when I start the car. Temps use dropped from the 70’s low 40’s here. Today after drinving a few miles I left it parked for about 45 minutes. When I started it up, not only did I get the irregular rumble, it really sputtered. As I started to drive it shuddered hard a couple times. I was sure it was going to stall. It’s never done that before. Once I got to a stop light, the electric motor took over, the rest of the ride was better though the rumble was quietly noticeable. I have an appointment at the dealership next week. Hoping it will make the sound for them. Any advice on whether to drive it in the meantime? I don’t want to really do damage to the gas engine or anything else. ?

[jzchen]

Is there a check engine light?  I wouldn’t drive it especially if there is.  If possible get it towed to a trusted mechanic.

[nogoodbum]

VTCAPAgirl, noting that the car only has 55k, means that it was only driven only about 5-6k per year. With electric use this may be actually only 4-5k per year. Would be helpful to know how the car was used in the year prior to your purchase, [short drives at low speed] or if was on dealer lot for any amount before purchase. From what you say, it sounds as this may be a fuel related problem, [bad-old gas or fuel injectors need cleaning]. I would put in some quality fuel cleaner & drive the car as the household primary [if you aren't doing that now] for a week or so & see if that will help, won't hurt, may help. This is with the assumption there is no check engine light. Thanks for the read.